Sunscreen: Difference between revisions
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https://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpegabeling standards have been evolving in the United States since the FDA first adopted the SPF calculation in 1978.<ref>{{cite journal |url=http://www.fda.gov/downloads/Drugs/DevelopmentApprovalProcess/DevelopmentResources/Over-the-CounterOTCDrugs/StatusofOTCRulemakings/ucm090127.pdf |title=Sunscreen Drug Products for Over-the-Counter Human Use |journal=[[Federal Register]] |author=Department of Health and Human Services: Food and Drug Administration |volume=43 |issue=166 |pages=38206–38269 |date=August 25, 1978 |accessdate=July 30, 2014}}</ref> The FDA issued a comprehensive set of rules in June 2011, taking effect in 2012–2013, designed to help consumers identify and select suitable sunscreen products offering protection from sunburn, early skin aging, and skin cancer:<ref name="fda2011" /><ref>{{cite journal|title=Sunscreen Drug Products for Over-the-Counter Human Use; Final Rules and Proposed Rules|journal=Federal Register|date=June 17, 2011|volume=76|issue=117|pages=35620–35665|url=http://www.gpo.gov/fdsys/pkg/FR-2011-06-17/pdf/2011-14766.pdf|accessdate=August 19, 2014|author=Department of Health and Human Services: Food and Drug Administration}}</ref><ref>{{cite journal |title=Sunscreen Drug Products for Over-the-Counter Human Use; Delay of Compliance Dates |journal=Federal Register |date=May 11, 2012 |volume=77 |issue=92 |pages=27591–27593 |url=http://www.gpo.gov/fdsys/pkg/FR-2012-05-11/pdf/2012-11390.pdf |accessdate=September 27, 2012 |author=Department of Health and Human Services: Food and Drug Administration}}</ref> |
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'''Sunscreen''', also known as '''sunblock''', '''sun cream''' or '''suntan lotion''', is a [[lotion]], spray, gel or other [[topical]] product that absorbs or reflects some of the [[sun]]'s [[ultraviolet]] (UV) radiation and thus helps protect against [[sunburn]]. Diligent use of sunscreen can also slow or temporarily prevent the development of wrinkles, moles and sagging skin. |
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Depending on the mode of action, sunscreens can be classified into physical sunscreens (i.e., those that reflect the sunlight) or chemical sunscreens (i.e., those that absorb the UV light). |
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Medical organizations such as the [[American Cancer Society]] recommend the use of sunscreen because it aids in the prevention of [[squamous cell carcinomas]].<ref>{{cite web|url=http://www.cancer.org/docroot/PED/content/ped_7_1_What_You_Need_To_Know_About_Skin_Cancer.asp|title=Skin Cancer - Skin Cancer Facts - Common Skin Cancer Types|website=www.cancer.org|deadurl=yes|archiveurl=https://web.archive.org/web/20080410204247/http://www.cancer.org/docroot/PED/content/ped_7_1_What_You_Need_To_Know_About_Skin_Cancer.asp|archivedate=April 10, 2008|df=mdy-all}}</ref> Many sunscreens do not block [[ultraviolet A|UVA]] radiation, which does not primarily cause sunburn but can increase the rate of [[melanoma]] and [[photodermatitis]].<ref>{{cite journal |author1=Poon, Terence SC Poon |author2=Barnetson, Ross StC |author3=Halliday, Gary M | title= Prevention of Immunosuppression by Sunscreens in Humans Is Unrelated to Protection from Erythema and Dependent on Protection from Ultraviolet A in the Face of Constant Ultraviolet B Protection | journal= J Invest Dermatol | volume=121 | pages=184–90 | year=2003 | doi=10.1046/j.1523-1747.2003.12317.x}}</ref> The use of broad-spectrum ([[Ultraviolet#Subtypes|UVA/UVB]]) sunscreens can address this concern. |
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Sunscreens are commonly rated and labeled with a sun protection factor (SPF) that measures the fraction of sunburn-producing UV rays that reach the skin. For example, "SPF 15" means that {{frac|1|15}} of the burning radiation reaches the skin through the recommended thickness of sunscreen. Other rating systems indicate the degree of protection from non-burning UVA radiation. |
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== Health effects == |
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{{see also|Health effects of sunlight exposure}} |
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=== Benefits === |
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Sunscreen use can help prevent [[melanoma]]<ref name=SunM>{{cite journal |vauthors=Kanavy HE, Gerstenblith MR | title = Ultraviolet radiation and melanoma | journal = Semin Cutan Med Surg | volume = 30 | issue = 4| pages = 222–8 |date=December 2011 | pmid = 22123420 | doi = 10.1016/j.sder.2011.08.003 }}</ref><ref name=WCR2014>{{cite book|title=World Cancer Report 2014.|date=2014|publisher=World Health Organization|isbn=9283204298|pages=Chapter 5.14}}</ref><ref>{{cite journal|last1=Azoury|first1=SC|last2=Lange|first2=JR|title=Epidemiology, risk factors, prevention, and early detection of melanoma.|journal=The Surgical clinics of North America|date=October 2014|volume=94|issue=5|pages=945–62, vii|pmid=25245960|doi=10.1016/j.suc.2014.07.013}}</ref> and [[squamous cell carcinoma]], two types of [[skin cancer]].<ref name=SunS>{{cite journal |author1=Burnett M.E. |author2=Wang S.Q. | title = Current sunscreen controversies: a critical review | journal = Photodermatology, Photoimmunology & Photomedicine | volume = 27 | issue = 2 | pages = 58–67 |date=April 2011 |pmid = 21392107 | doi = 10.1111/j.1600-0781.2011.00557.x }}</ref> There is little evidence that it is effective in preventing [[basal cell carcinoma]].<ref>{{cite journal |vauthors=Kütting B, Drexler H |title = UV-induced skin cancer at workplace and evidence-based prevention | journal = Int Arch Occup Environ Health |volume = 83 | issue = 8 | pages = 843–54 |date=December 2010 | pmid = 20414668 | doi = 10.1007/s00420-010-0532-4 }}</ref> |
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A 2013 study concluded that the diligent, everyday application of sunscreen can slow or temporarily prevent the development of wrinkles and sagging skin.<ref name=wrinkles>{{cite journal|url=http://annals.org/article.aspx?articleid=1691732|title=Sunscreen and Prevention of Skin Aging|journal=Annals of Internal Medicine|date=June 4, 2013|authors=Hughes, MCB; Williams, GM; Baker, P; Green, AC|volume=158|issue=11|pages=781–790|doi=10.7326/0003-4819-158-11-201306040-00002}}</ref> The study involved 900 [[light skin|white]] people in Australia and required some of them to apply a broad-spectrum sunscreen every day for four and a half years. It found that people who did so had noticeably more resilient and smoother skin than those assigned to continue their usual practices.<ref name=wrinkles/> |
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Minimizing UV damage is especially important for children and fair-skinned individuals and those who have [[Photosensitivity in humans|sun sensitivity]] for medical reasons.<ref>{{cite web|url=http://ohioline.osu.edu/cd-fact/pdf/0199.pdf |archive-url=https://web.archive.org/web/20080512053158/http://ohioline.osu.edu/cd-fact/pdf/0199.pdf |dead-url=yes |archive-date=2008-05-12 |author1=Dresbach S.H. |author2=Brown W. |title=Ultraviolet Radiation |work=Ohioline Fact Sheet Series |volume=CDFS-199-08 |publisher=Ohio State University Extension |date=2008 }}</ref> |
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=== Potential risks === |
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In 2009, the [[Therapeutic Goods Administration]] of Australia updated a review of sunscreen safety studies and concluded: "The potential for [[titanium dioxide]] (TiO<sub>2</sub>) and [[zinc oxide]] (ZnO) [[nanoparticle]]s in sunscreens to cause adverse effects depend primarily upon the ability of the nanoparticles to reach viable skin cells. To date, the current weight of evidence suggests that TiO<sub>2</sub> and ZnO nanoparticles do not reach viable skin cells."<ref>{{cite web |url=http://www.tga.gov.au///npmeds/sunscreen-zotd.pdf |title=A review of the scientific literature on the safety of nanoparticulate titanium dioxide or zinc oxide in sunscreens |author=Australian Government: [[Therapeutic Goods Administration]] |date=July 2009 |accessdate=June 15, 2015 |deadurl=unfit |archiveurl=https://web.archive.org/web/20110406145019/http://www.tga.gov.au///npmeds/sunscreen-zotd.pdf |archivedate=April 6, 2011 }}</ref> Sunscreen ingredients typically undergo extensive review by government regulators in multiple countries, and ingredients that present significant safety concerns (such as [[Para-aminobenzoic acid|PABA]]) tend to be withdrawn from the consumer market.<ref name=lim/> |
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Concerns have also been raised about potential [[vitamin D deficiency]] arising from prolonged use of sunscreen. Typical use of sunscreen does not usually result in vitamin D deficiency; however, extensive usage may.<ref>{{cite journal|last1=Norval|first1=M|last2=Wulf|first2=HC|title=Does chronic sunscreen use reduce vitamin D production to insufficient levels?|journal=The British Journal of Dermatology|date=October 2009|volume=161|issue=4|pages=732–6|pmid=19663879|doi=10.1111/j.1365-2133.2009.09332.x}}</ref> Sunscreen prevents ultraviolet light from reaching the skin, and even moderate protection can substantially reduce vitamin D synthesis.<ref>{{cite journal |author=Holick MF |title=Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease |journal=Am. J. Clin. Nutr. |volume=80 |issue=6 Suppl |pages=1678S–1688S |date=December 2004 |pmid=15585788 |doi= |url=http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=15585788}}</ref><ref>{{cite journal|last1=Sayre |first1=Robert M. |last2=Dowdy |first2=John C. |year=2007 |title=Darkness at Noon: Sunscreens and Vitamin D<sub>3</sub> |journal=Photochemistry and Photobiology |volume=83 |issue=2 |pages=459–463 |doi=10.1562/2006-06-29-RC-956 |url=http://www.blackwell-synergy.com/doi/abs/10.1562/2006-06-29-RC-956 |pmid=17115796}}</ref> However, adequate amounts of vitamin D can be produced with moderate sun exposure to the face, arms and legs, averaging 5–30 minutes twice per week without sunscreen. (The darker the complexion, or the weaker the sunlight, the more minutes of exposure are needed, approximating 25% of the time for minimal sunburn. Vitamin D overdose is impossible from UV exposure thanks to an equilibrium the skin reaches in which vitamin D degrades as fast as it is created.<ref>{{cite journal |author=Holick MF |date=February 2002 |title=Vitamin D: the underappreciated D-lightful hormone that is important for skeletal and cellular health |journal=Current Opinion in Endocrinology, Diabetes and Obesity |volume=9 |issue=1 |pages=87–98 |doi=10.1097/00060793-200202000-00011}}</ref><ref>{{cite journal |author=Holick MF |title=Sunlight and Vitamin D |journal=Journal of General Internal Medicine |volume=17 |issue=9 |pages=733–735 |date=September 2002 |pmc=1495109 |doi=10.1046/j.1525-1497.2002.20731.x |pmid=12220371}}</ref><ref>{{cite journal |author=Holick MF |title=Vitamin D deficiency |journal=The New England Journal of Medicine |volume=357 |issue=3 |pages=266–281 |date=July 2007 |pmid=17634462 |doi=10.1056/NEJMra070553}}</ref> |
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== Measurements of protection == |
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[[File:Sunburn blisters.jpg|thumb |upright=1.3 | Sunscreen helps prevent [[sunburn]], such as this, which has blistered.]] |
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=== Sun protection factor and labeling {{anchor | Sun Protection Factor}} === |
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[[Image:UV and Vis Sunscreen.jpg|thumb |upright=1.3 | Two photographs showing the effect of applying sunscreens in visible light and in UVA. The photograph on the right was taken using [[ultraviolet photography]] shortly after application of sunscreen to half of the face.]] |
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The sun protection factor (SPF rating, introduced in 1974) is a measure of the fraction of sunburn-producing UV rays that reach the skin. For example, "SPF 15" means that {{frac|1|15}} of the burning radiation will reach the skin, assuming sunscreen is applied evenly at a thick [[Sunscreen#Dosage|dosage]] of 2 milligrams per square centimeter (mg/cm<sup>2</sup>). A user can determine the effectiveness of a sunscreen "by multiplying the SPF factor by the length of time it takes for him or her to suffer a burn without sunscreen."<ref name="Sunblock.">[http://www.dermatology.ucsf.edu/skincancer/General/prevention/Sunscreen.aspx ''Sunblock.''] {{webarchive|url=https://web.archive.org/web/20140601125802/http://www.dermatology.ucsf.edu/skincancer/General/prevention/Sunscreen.aspx |date=June 1, 2014 }} UCSF. School of Medicine. Dept of Dermatology.</ref> Thus, if a person develops a sunburn in 10 minutes when not wearing a sunscreen, the same person in the same intensity of sunlight will avoid sunburn for 150 minutes if wearing a sunscreen with an SPF of 15.<ref name="Sunblock."/> It is important to note that sunscreens with higher SPF do not last or remain effective on the skin any longer than lower SPF and must be continually reapplied as directed, usually every two hours.<ref>{{cite web| url=http://www.aad.org/media-resources/stats-and-facts/prevention-and-care/sunscreens |title=Sunscreen FAQs |publisher=American Academy of Dermatology |accessdate=July 22, 2014}}</ref> |
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The SPF is an imperfect measure of skin damage because invisible damage and skin aging are also caused by [[ultraviolet]] type A (UVA, wavelengths 315–400 or 320–400 [[nanometre|nm]]), which does not primarily cause reddening or pain. Conventional sunscreen blocks very little UVA radiation relative to the nominal SPF; broad-spectrum sunscreens are designed to protect against both UVB and UVA.<ref>{{Cite journal| pmid = 12118426| year = 2002| last1 = Stege | first1 = H.| last2 = Budde| last3 = Grether-Beck| last4 = Richard| last5 = Rougier| last6 = Ruzicka| last7 = Krutmann| title = Sunscreens with high SPF values are not equivalent in protection from UVA induced polymorphous light eruption| volume = 12| issue = 4| pages = IV–VI| journal = European journal of dermatology : EJD}}</ref><ref>{{Cite journal| last1 = Haywood | first1 = R.| last2 = Wardman | first2 = P.| last3 = Sanders | first3 = R.| last4 = Linge | first4 = C.| title = Sunscreens inadequately protect against ultraviolet-A-induced free radicals in skin: implications for skin aging and melanoma?| journal = The Journal of Investigative Dermatology| volume = 121| issue = 4| pages = 862–868| year = 2003| pmid = 14632206| doi = 10.1046/j.1523-1747.2003.12498.x }}</ref><ref>{{Cite journal| last1 = Moyal | first1 = D.| last2 = Fourtanier | first2 = A.| title = Broad-spectrum sunscreens provide better protection from solar ultraviolet-simulated radiation and natural sunlight-induced immunosuppression in human beings| journal = Journal of the American Academy of Dermatology| volume = 58| issue = 5 Suppl 2| pages = S149–S154| year = 2008| pmid = 18410801 | doi = 10.1016/j.jaad.2007.04.035 }}</ref> According to a 2004 study, UVA also causes [[DNA repair#DNA damage|DNA damage]] to cells deep within the skin, increasing the risk of [[malignant melanoma]]s.<ref>{{cite journal |vauthors=Berneburg M, Plettenberg H, Medve-König K, Pfahlberg A, Gers-Barlag H, Gefeller O, Krutmann J | title=Induction of the photoaging-associated mitochondrial common deletion in vivo in normal human skin | journal=J Invest Dermatol | volume=122 | issue=5 | pages=1277–83 | year=2004 | pmid=15140232 | doi=10.1111/j.0022-202X.2004.22502.x}}</ref> Even some products labeled "broad-spectrum UVA/UVB protection" have not always provided good protection against UVA rays.<ref>{{cite news |url=http://www.nbcnews.com/id/12081374/ |title=Sunscreen makers sued for misleading claims |agency=Associated Press |date=April 24, 2006 |accessdate=January 5, 2015}}</ref> [[Titanium dioxide]] probably gives good protection, but does not completely cover the UVA spectrum, as early 2000s research suggests that zinc oxide is superior to titanium dioxide at wavelengths 340–380 nm.<ref>{{cite journal | vauthors=Pinnell SR, Fairhurst D, Gillies R, Mitchnick MA, Kollias N | title=Microfine zinc oxide is a superior sunscreen ingredient to microfine titanium dioxide | journal=Dermatol Surg | volume=26 | issue=4 | pages=309–14 | date=April 2000 | pmid=10759815 | doi=10.1046/j.1524-4725.2000.99237.x | url=http://www.blackwell-synergy.com/openurl?genre=article&sid=nlm:pubmed&issn=1076-0512&date=2000&volume=26&issue=4&spage=309 }}{{dead link|date=February 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> |
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Owing to consumer confusion over the real degree and duration of protection offered, labeling restrictions are enforced in several countries. In the [[European Union|EU]], sunscreen labels can only go up to SPF 50+ (initially listed as 30 but soon revised to 50).<ref>{{cite journal | url=http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32006H0647:EN:NOT | title=Commission Recommendation of 22 September 2006 on the efficacy of sunscreen products and the claims made relating thereto | publisher=Official Journal of the European Union | date=2006-09-22 | accessdate=2009-09-25}}</ref> [[Australia]]'s [[Therapeutic Goods Administration]] increased the upper limit to 50+ in 2012.<ref>{{cite web | url=http://www.arpansa.gov.au/uvrg/rginfo_p13.cfm | title=UV Resource Guide - Sunscreens | publisher=Arpansa | date=2008-12-20 | accessdate=2009-09-25 | deadurl=yes | archiveurl=https://web.archive.org/web/20091119074507/http://www.arpansa.gov.au/uvrg/rginfo_p13.cfm | archivedate=November 19, 2009 | df=mdy-all }}</ref><ref>{{cite web | url=http://www.cancer.org.au/preventing-cancer/sun-protection/preventing-skin-cancer/spf50sunscreen.html | title=SPF50+ Sunscreen | date=2013-02-01 | accessdate=2014-02-06}}</ref> In its 2007 and 2011 draft rules, the US [[Food and Drug Administration]] (FDA) proposed a maximum SPF label of 50, to limit unrealistic claims.<ref name="qa2007">{{cite web|url=http://www.fda.gov/cder/drug/infopage/sunscreen/qa.htm|title=Questions and Answers on the 2007 Sunscreen Proposed Rule|publisher=|deadurl=yes|archiveurl=https://web.archive.org/web/20080921135529/http://www.fda.gov/CDER/drug/infopage/sunscreen/qa.htm|archivedate=September 21, 2008|df=mdy-all}}</ref><ref name="fda2011">{{cite web | url=http://www.fda.gov/Drugs/ResourcesForYou/Consumers/BuyingUsingMedicineSafely/UnderstandingOver-the-CounterMedicines/ucm258468.htm | title=Questions and Answers: FDA announces new requirements for over-the-counter (OTC) sunscreen products marketed in the U.S. | date=2011-06-23 | accessdate=2012-04-10}}</ref><ref>{{cite journal |title=Revised Effectiveness Determination; Sunscreen Drug Products for Over-the-Counter Human Use |journal=[[Federal Register]] |date=June 17, 2011 |volume=76 |issue=117 |pages=35672–35678 |url=http://www.fda.gov/downloads/Drugs/DevelopmentApprovalProcess/DevelopmentResources/Over-the-CounterOTCDrugs/StatusofOTCRulemakings/UCM313542.pdf |accessdate=November 21, 2013|author=Department of Health and Human Services: Food and Drug Administration}}</ref> (As of February 2017, the FDA has not adopted the SPF 50 limit.<ref>{{cite web|url=https://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/Over-the-CounterOTCDrugs/StatusofOTCRulemakings/ucm072134.htm|title=Status of OTC Rulemakings - Rulemaking History for OTC Sunscreen Drug Products|first=Center for Drug Evaluation and|last=Research|website=www.fda.gov}}</ref>) Others have proposed restricting the active ingredients to an SPF of no more than 50, due to lack of evidence that higher dosages provide more meaningful protection.<ref name="onpoint">{{cite web | url=http://onpoint.wbur.org/2011/06/16/sunscreen | date=2011-06-16 | accessdate=2012-04-10 | title=Sunscreen Takes Some Heat: New Dangers, New Rules}}</ref> Different sunscreen ingredients have different effectiveness against UVA and UVB.<ref>{{cite web|title=The Burning Facts|url=https://www.epa.gov/sites/production/files/documents/sunscreen.pdf|accessdate=1 December 2017|date=2006}}</ref> |
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[[Image:erythemal action spectrum.svg|thumb|upright=1.3 | UV sunlight spectrum (on a summer day in the Netherlands), along with the CIE Erythemal action spectrum. The effective spectrum is the product of the former two.]] |
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The SPF can be measured by applying sunscreen to the skin of a volunteer and measuring how long it takes before sunburn occurs when exposed to an artificial sunlight source. In the US, such an ''[[in vivo]]'' test is required by the FDA. It can also be measured ''[[in vitro]]'' with the help of a specially designed [[spectrometer]]. In this case, the actual [[transmittance]] of the sunscreen is measured, along with the degradation of the product due to being exposed to sunlight. In this case, the transmittance of the sunscreen must be measured over all wavelengths in sunlight's UVB–UVA range (290–400 nm), along with a table of how effective various wavelengths are in causing sunburn (the ''erythemal action spectrum'') and the standard intensity [[spectrum]] of sunlight (see the figure). Such ''in vitro'' measurements agree very well with ''in vivo'' measurements {{Attribution needed|date=September 2016}}. |
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Numerous methods have been devised for evaluation of UVA and UVB protection. The most-reliable spectrophotochemical methods eliminate the subjective nature of grading [[erythema]].<ref>{{cite journal |first=Dominique |last=Moyal |title=How to measure UVA protection afforded by suncreen products |url=http://www.medscape.com/viewarticle/576849 |journal=Expert Rev. Dermatol. |date=June 2008 |volume=3 |issue=3 |pages=307–313 |doi=10.1586/17469872.3.3.307}}</ref> |
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The ultraviolet protection factor (UPF) is a similar scale developed for rating fabrics for [[sun protective clothing]]. According to recent testing by ''[[Consumer Reports]]'', UPF ~30 is typical for protective fabrics, while UPF ~6 is typical for standard summer fabrics.<ref>{{cite journal |url= http://www.consumerreports.org/cro/magazine/2014/07/what-to-know-about-sunscreen-before-buying-it/ |title=What to Know About Sunscreen Before Buying It |magazine=Consumer Reports |date=May 2014 |accessdate=December 20, 2014}}</ref> |
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Mathematically, the SPF (or the UPF) is calculated from measured data as |
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:<math>\mathrm{SPF} = \frac{\int A(\lambda) E(\lambda)d\lambda}{\int A(\lambda) E(\lambda)/\mathrm{MPF}(\lambda) \, d\lambda},</math> |
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where <math>E(\lambda)</math> is the solar irradiance spectrum, <math>A(\lambda)</math> the erythemal action spectrum, and <math>\mathrm{MPF}(\lambda)</math> the monochromatic protection factor, all functions of the wavelength <math>\lambda</math>. The MPF is roughly the inverse of the transmittance at a given wavelength. |
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The above means that the SPF is not simply the inverse of the transmittance in the UVB region. If that were true, then applying two layers of SPF 5 sunscreen would always be equivalent to SPF 25 (5 times 5). The actual combined SPF may be lower than the square of the single-layer SPF.<ref name=squared/> |
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=== UVA protection === |
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==== Persistent pigment darkening ==== |
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The persistent pigment darkening (PPD) method is a method of measuring UVA protection, similar to the SPF method of measuring sunburn protection. Originally developed in Japan, it is the preferred method used by manufacturers such as [[L'Oréal]]. |
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Instead of measuring [[erythema]] or reddening of the skin, the PPD method uses UVA radiation to cause a persistent darkening or tanning of the skin. Theoretically, a sunscreen with a PPD rating of 10 should allow a person 10 times as much UVA exposure as would be without protection. The PPD method is an ''[[in vivo]]'' test like SPF. In addition, Colipa has introduced a method that, it is claimed, can measure this ''[[in vitro]]'' and provide parity with the PPD method.<ref>{{cite web|url=http://www.colipa.com/site/index.cfm?SID=15588&OBJ=28546&back=1 |title=www.colipa.com |date=June 9, 2008 |publisher= |deadurl=bot: unknown |archiveurl=https://web.archive.org/web/20080609221030/http://www.colipa.com/site/index.cfm?SID=15588&OBJ=28546&back=1 |archivedate=June 9, 2008 |df= }}</ref> |
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==== SPF equivalence ==== |
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[[File:UVA logo.svg|thumb | 125px | The UVA seal used in the [[European Union|EU]]]] |
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[[File:SPF15SunBlock.JPG|thumb|175px | | A tube of SPF 15 sun lotion]] |
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As part of revised guidelines for sunscreens in the EU, there is a requirement to provide the consumer with a minimum level of UVA protection in relation to the SPF. This should be a "UVA PF" of at least 1/3 of the SPF to carry the UVA seal.<ref>{{cite web|url=https://www.cosmeticseurope.eu/using-cosmetics-colipa-the-european-cosmetic-cosmetics-association/sun-products/the-european-commission-recommendation-on-the-efficacy-of-sunscreen-products.html|title=www.cosmeticseurope.eu|publisher=|deadurl=yes|archiveurl=https://web.archive.org/web/20140826114843/https://www.cosmeticseurope.eu/using-cosmetics-colipa-the-european-cosmetic-cosmetics-association/sun-products/the-european-commission-recommendation-on-the-efficacy-of-sunscreen-products.html|archivedate=August 26, 2014|df=mdy-all}}</ref> |
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A set of final US FDA rules effective from summer 2012 defines the phrase "broad spectrum" as providing UVA protection proportional to the UVB protection, using a standardized testing method.<ref name="fda2011" /> |
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==== Star rating system ==== |
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In the UK and Ireland, the [[Boots (chemist)|Boots]] star rating system is a proprietary ''[[in vitro]]'' method used to describe the ratio of UVA to UVB protection offered by sunscreen creams and sprays. Based on original work by Brian Diffey at Newcastle University, the Boots Company in Nottingham, UK, developed a method that has been widely adopted by companies marketing these products in the UK. |
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One-star products provide the lowest ratio of UVA protection, five-star products the highest. The method was recently revised in light of the Colipa UVA PF test and the revised EU recommendations regarding UVA PF. The method still uses a [[spectrophotometer]] to measure absorption of UVA versus UVB; the difference stems from a requirement to pre-irradiate samples (where this was not previously required) to give a better indication of UVA protection and photostability when the product is used. With the current methodology, the lowest rating is three stars, the highest being five stars. |
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In August 2007, the FDA put out for consultation the proposal that a version of this protocol be used to inform users of American product of the protection that it gives against UVA;<ref name="qa2007"/> but this was not adopted, for fear it would be too confusing.<ref name="onpoint" /> |
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==== PA system ==== |
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Asian brands, particularly Japanese ones, tend to use The Protection Grade of UVA (PA) system to measure the UVA protection that a sunscreen provides. The PA system is based on the PPD reaction and is now widely adopted on the labels of sunscreens. According to the Japan Cosmetic Industry Association, PA+ corresponds to a UVA protection factor between two and four, PA++ between four and eight, and PA+++ more than eight. This system was revised in 2013 to include PA++++ which corresponds to a PPD rating of sixteen or above. |
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== Sunblock == |
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Sunblock typically refers to opaque sunscreen that is effective at blocking both UVA and UVB rays and uses a heavy carrier oil to resist being washed off. [[Titanium dioxide]] and [[zinc oxide]] are two minerals that are used in sunblock.<ref name="americanelements">{{cite web|title=Nanotechnology Information Center: Properties, Applications, Research, and Safety Guidelines|url=http://www.americanelements.com/nanotech.htm|publisher=[[American Elements]]}}</ref> |
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The use of the word "sunblock" in the marketing of sunscreens is controversial. Since 2013, the FDA has banned such use because it can lead consumers to overestimate the effectiveness of products so labeled.<ref name="fda2011"/> Nonetheless, many consumers use the words sunblock and sunscreen synonymously. |
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For total protection against damage from the sun, the skin needs to be protected from UVA, UVB, and also IRA ([[infrared]]-A light).<ref>{{cite journal |vauthors=Schroeder P, Krutmann J |url=http://www.skintherapyletter.com/2010/15.4/2.html |title=What is Needed for a Sunscreen to Provide Complete Protection |journal=Skin Therapy Letter |volume=15 |number=4 |date=April 2010}}</ref> Roughly 35% of solar energy is IRA.{{citation needed|date=September 2016}}. However, note that there is continuing debate within the dermatology community over the impact of sun-sourced IRA: Some sources indicate that early morning IRA exposure may be protective against further sun exposure by increasing cell proliferation and initiating anti-inflammatory cascades; these effects are not observed for artificial sources of intense IRA.<ref>Barolet, Daniel, François Christiaens, and Michael R. Hamblin. "Infrared and skin: Friend or foe." Journal of Photochemistry and Photobiology B: Biology 155 (2016): 78-85.</ref> |
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== Active ingredients == |
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In addition to [[moisturizer]]s and other inactive ingredients, sunscreens contain one or more of the following active ingredients, which are either chemical or mineral in nature: |
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* [[organic chemistry|Organic chemical]] compounds that absorb ultraviolet light. |
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* Inorganic [[Suspended solids|particulates]] that reflect, scatter, and absorb UV light (such as [[titanium dioxide]], [[zinc oxide]], or a combination of both).<ref name="americanelements" /> |
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* Organic particulates that mostly absorb UV light like organic chemical compounds, but contain multiple [[chromophores]] that reflect and scatter a fraction of light like inorganic particulates. An example is [[Bisoctrizole|Tinosorb M]]. The mode of action is about 90% by absorption and 10% by scattering. |
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The principal active ingredients in sunscreens are usually [[aromaticity|aromatic]] molecules [[conjugated system|conjugated]] with [[carbonyl]] groups. This general structure allows the molecule to absorb high-energy ultraviolet rays and release the energy as lower-energy rays, thereby preventing the skin-damaging ultraviolet rays from reaching the skin. So, upon exposure to UV light, most of the ingredients (with the notable exception of [[avobenzone]]) do not undergo significant chemical change, allowing these ingredients to retain the UV-absorbing potency without significant [[photodegradation]].<ref name= CTFA1998 /> A chemical stabilizer is included in some sunscreens containing avobenzone to slow its breakdown; examples include formulations containing [[Helioplex]]<ref>{{cite web|url=http://www.realsimplerewards.com/rsn/microsites/neutrogena_helioplex.html|title=REAL SIMPLE Rewards Program|website=www.realsimplerewards.com}}</ref> and AvoTriplex.<ref>{{cite web|url=http://www.bananaboat.com/avotriplex/index.html|title=Sun Protection - Banana Boat|website=www.bananaboat.com}}{{dead link|date=September 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The stability of avobenzone can also be improved by [[bemotrizinol]],<ref>{{cite journal| title=Photostabilization of Butyl methoxydibenzoylmethane (Avobenzone) and Ethylhexyl methoxycinnamate by Bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S), a new UV broadband filter|date=September 2001 | pmid=11594052|vauthors=Chatelain E, Gabard B | journal=Photochem Photobiol | volume=74 | pages=401–6| doi=10.1562/0031-8655(2001)074<0401:POBMAA>2.0.CO;2| issue=3}}</ref> [[octocrylene]]<ref>{{cite web|url=http://www.dsm.com/en_US/html/dnpus/pe_parsol_340.htm |publisher=DSM |title=Parsol 340 – Octocrylene |accessdate=June 22, 2015 |deadurl=unfit |archiveurl=https://web.archive.org/web/20090803112741/http://www.dsm.com/en_US/html/dnpus/pe_parsol_340.htm |archivedate=August 3, 2009 }}</ref> and various other photostabilisers. Most organic compounds in sunscreens slowly degrade and become less effective over the course of several years if stored properly, resulting in the [[shelf life|expiration dates]] calculated for the product.<ref>{{cite web |url=http://www.skincancer.org/skin-cancer-information/ask-the-experts/does-sunscreen-become-ineffective-with-age |title=Does sunscreen become ineffective with age? |last=Burke |first=Karen E. |publisher=The Skin Cancer Foundation |accessdate=July 31, 2014}}</ref> |
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Sunscreening agents are used in some hair care products such as shampoos, conditioners and styling agents to protect against protein degradation and color loss. Currently, [[benzophenone-4]] and [[ethylhexyl methoxycinnamate]] are the two sunscreens most commonly used in hair products. The common sunscreens used on skin are rarely used for hair products due to their texture and weight effects. |
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The following are the FDA allowable active ingredients in sunscreens: |
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{{anchor|table}} |
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{| class="wikitable" |
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! UV-filter |
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! Other names |
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! Maximum concentration |
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! Permitted in these countries |
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! Results of safety testing |
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! UVA |
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! UVB |
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|- |
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| [[p-Aminobenzoic acid]] |
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| PABA |
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| 15% (EU: banned from sale to consumers from 8 October 2009) |
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| USA, AUS |
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| Protects against skin tumors in mice.<ref>{{cite journal| authors= Flindt-Hansen, H; Thune, P; Eeg-Larsen, T |title=The inhibiting effect of PABA on photocarcinogenesis |journal=Archives of Dermatological Research|volume=282|pages=38–41|year=1990|doi=10.1007/BF00505643| pmid= 2317082| issue= 1}}</ref><ref>{{cite journal| authors= Flindt-Hansen, H; Thune, P; Eeg-Larsen, T |title= The effect of short-term application of PABA on photocarcinogenesis |journal= Acta Derm Venereol.|volume=70|pages=72–75|year=1990| pmid= 1967881| issue= 1}}</ref><ref name="Sensitization">{{cite journal| authors=Osgood, PJ; Moss, SH; Davies, DJ | title=The sensitization of near-ultraviolet radiation killing of mammalian cells by the sunscreen agent para-aminobenzoic acid| journal=Journal of Investigative Dermatology| volume=79| issue=6| pages=354–357| year=1982| doi=10.1111/1523-1747.ep12529409| pmid=6982950}}</ref> Shown to increase DNA defects, however, and is now less commonly used. |
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| |
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| X |
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|- |
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| [[Padimate O]] |
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| OD-PABA, octyldimethyl-PABA, σ-PABA |
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| 8% (EU, USA, AUS) 10% (JP) |
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(Not currently supported in EU and may be delisted) |
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| EU, USA, AUS, JP |
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| |
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| |
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| X |
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|- |
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| [[Phenylbenzimidazole sulfonic acid]] |
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| Ensulizole, Eusolex 232, PBSA, Parsol HS |
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| 4% (US, AUS) 8% (EU) 3% (JP) |
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| EU, USA, AUS, JP |
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| Genotoxic in bacteria<ref name="Mosley2007">{{cite journal |year= 2007 |month= |title= Light-Induced Cytotoxicity and Genotoxicity of a Sunscreen Agent, 2-Phenylbenzimidazol in Salmonella typhimurium TA 102 and HaCaT Keratinocytes |journal= International Journal of Environmental Research and Public Health |volume= 4 |issue= 2 |pages=126–131 |id= |url= |doi=10.3390/ijerph2007040006 |author1= Mosley, C N |author2= Wang, L |author3= Gilley, S |author4= Wang, S |author5= Yu, H |pmid= 17617675}}</ref> |
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| |
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| X |
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|- |
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| [[Cinoxate]] |
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| 2-Ethoxyethyl p-methoxycinnamate |
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| 3% (US) 6% (AUS) |
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| USA, AUS |
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| |
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| X |
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| X |
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|- |
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| [[Dioxybenzone]] |
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| Benzophenone-8 |
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| 3% |
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| USA, AUS |
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| |
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| X |
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| X |
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|- |
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| [[Oxybenzone]] |
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| Benzophenone-3, Eusolex 4360, Escalol 567 |
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| 6% (US) 10% (AUS, EU) 5% (JP) |
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| EU, USA, AUS, JP |
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| |
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| X |
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| X |
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|- |
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| [[Homosalate]] |
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| Homomethyl salicylate, HMS |
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| 10% (EU, JP) 15% (US, AUS) |
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| EU, USA, AUS, JP |
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| |
|||
| |
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| X |
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|- |
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| [[Menthyl anthranilate]] |
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| Meradimate |
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| 5% |
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| USA, AUS |
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| |
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| X |
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| |
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|- |
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| [[Octocrylene]] |
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| Eusolex OCR, Parsol 340, 2-Cyano-3,3-diphenyl acrylic acid, 2-ethylhexylester |
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| 10% |
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| EU, USA, AUS, JP |
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| Increases [[reactive oxygen species|ROS]]<ref name="Hanson">{{cite journal |author1=Hanson, KM |author2=Gratton, E |author3=Bardeen, CJ | title=Sunscreen enhancement of UV-induced reactive oxygen species in the skin | doi=10.1016/j.freeradbiomed.2006.06.011 | journal=Free Radical Biology and Medicine | year=2006 | volume=41 | pmid=17015167 | issue=8 | pages=1205–12}}</ref> |
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| X |
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| X |
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|- |
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| [[Octyl methoxycinnamate]] |
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| Octinoxate, EMC, OMC, Ethylhexyl methoxycinnamate, Escalol 557, 2-Ethylhexyl-paramethoxycinnamate, Parsol MCX |
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| 7.5% (US) 10% (EU, AUS) 20% (JP) |
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| EU, USA, AUS, JP |
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| |
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| |
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| X |
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|- |
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| [[Octyl salicylate]] |
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| Octisalate, 2-Ethylhexyl salicylate, Escalol 587, |
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| 5% (EU, USA, AUS) 10% (JP) |
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| EU, USA, AUS, JP |
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| |
|||
| |
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| X |
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|- |
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| [[Sulisobenzone]] |
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| 2-Hydroxy-4-Methoxybenzophenone-5-sulfonic acid, 3-Benzoyl-4-hydroxy-6-methoxybenzenesulfonic acid, Benzophenone-4, Escalol 577 |
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| 5% (EU) 10% (US, AUS, JP) |
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| EU, USA, AUS, JP |
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| |
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| X |
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| X |
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|- |
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| [[Trolamine salicylate]] |
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| Triethanolamine salicylate |
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| 12% |
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| USA, AUS |
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| |
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| |
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| X |
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|- |
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| [[Avobenzone]] |
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| 1-(4-methoxyphenyl)-3-(4-tert-butyl<br>phenyl)propane-1,3-dione, Butyl methoxy dibenzoylmethane, BMDBM, Parsol 1789, Eusolex 9020 |
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| 3% (US) 5% (EU, AUS) 10% (JP) |
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| EU, USA, AUS, JP |
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| |
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| X |
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| |
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|- |
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| [[Ecamsule]] |
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| Mexoryl SX, Terephthalylidene Dicamphor Sulfonic Acid |
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| 10% |
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| EU, AUS (US: approved in certain formulations up to 3% via New Drug Application (NDA) Route) |
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| Protects against skin tumors in mice<ref name="autogenerated1">{{cite journal |title= photoprotection | journal= Lancet |volume=370 |pages=528–37 |year=2007 |doi=10.1016/S0140-6736(07)60638-2 |author1= Lautenschlager, Stephan |author2= Wulf, Hans Christian |author3= Pittelkow, Mark R |pmid= 17693182 |issue= 9586}}</ref><ref>{{cite journal| title=Percutaneous absorption of Mexoryl SX in human volunteers: comparison with in vitro data|date=Nov–Dec 2003| pmid=14528058|vauthors=Benech-Kieffer F, Meuling WJ, Leclerc C, Roza L, Leclaire J, Nohynek G | journal= Skin Pharmacol Appl Skin Physiol| volume=16| pages=343–55| doi=10.1159/000072929| issue=6}}</ref><ref>{{cite journal| title=Mexoryl SX protects against solar-simulated UVR-induced photocarcinogenesis in mice|date=October 1996| pmid=8863475| author=Fourtanier A| journal= Photochem Photobiol| volume=64| pages=688–93| doi=10.1111/j.1751-1097.1996.tb03125.x| issue=4}}</ref> |
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| X |
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| |
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|- |
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| [[Titanium dioxide]] |
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| CI77891 |
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| 25% (US) No limit (JP) |
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| EU, USA, AUS, JP |
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| |
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| X |
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| X |
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|- |
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| [[Zinc oxide]] |
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| |
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| 25% (US) No limit (AUS, JP) |
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| EU, USA, AUS, JP |
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| Protects against skin tumors in mice<ref name="autogenerated1" /> |
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| X |
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| X |
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|} |
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Zinc oxide was approved as a UV filter by the EU in 2016.<ref>{{Cite web|url=http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32016R0621&from=EN|title=Amending Annex VI to Regulation (EC) No 1223/2009 of the European Parliament and of the Council on cosmetic products|last=|first=|date=2016-04-21|website=eur-lex.europa.eu|access-date=2017-03-22}}</ref> |
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Other ingredients approved within the EU<ref name="euregulation">{{cite journal |url=http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32009R1223&qid=1406148728060&from=EN |title=Regulation No. 1223/2009 on cosmetic products |journal=Official Journal of the European Union |date=December 22, 2009 |accessdate=May 26, 2015}}</ref> and other parts of the world,<ref>{{cite web |url=http://www.tga.gov.au/publication/australian-regulatory-guidelines-sunscreens-args |title=Australian Regulatory Guidelines for Sunscreens |author=Australian Government: [[Therapeutic Goods Administration]] |date=November 2012 |accessdate=June 21, 2015}}</ref> that have not been included in the current FDA Monograph: |
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{| class="wikitable" |
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! UV-filter |
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! Other names |
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! Maximum concentration |
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! Permitted in |
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|- |
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| [[4-Methylbenzylidene camphor]] |
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| Enzacamene, Parsol 5000, Eusolex 6300, MBC |
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| 4%<sup>*</sup> |
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| EU, AUS |
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|- |
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| [[Bisoctrizole|Parsol Max, Tinosorb M]] |
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| Bisoctrizole, Methylene Bis-Benzotriazolyl Tetramethylbutylphenol, MBBT |
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| 10%<sup>*</sup> |
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| EU, AUS, JP |
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|- |
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| [[Bemotrizinol|Parsol Shield, Tinosorb S]] |
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| Bis-ethylhexyloxyphenol methoxyphenol triazine, Bemotrizinol, BEMT, anisotriazine |
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| 10% (EU, AUS) 3% (JP)<sup>*</sup> |
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| EU, AUS, JP |
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|- |
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| Tinosorb A2B |
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| Tris-Biphenyl Triazine |
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| 10% |
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| EU |
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|- |
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| [[Bisdisulizole disodium|Neo Heliopan AP]] |
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| Bisdisulizole Disodium, Disodium phenyl dibenzimidazole tetrasulfonate, bisimidazylate, DPDT |
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| 10% |
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| EU, AUS |
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|- |
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| [[Drometrizole trisiloxane|Mexoryl XL]] |
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| Drometrizole Trisiloxane |
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| 15% |
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| EU, AUS |
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|- |
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| [[Benzophenone-n|Benzophenone-9]] |
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| Uvinul DS 49, CAS 3121-60-6, Sodium Dihydroxy Dimethoxy Disulfobenzophenone <ref>{{cite web|url=http://www.basf-korea.co.kr/02_products/04_finechemicals/document/cosmetic/tech/uvabsorber/down.asp?file=uvinulgrades.pdf |title=Uvinul Grades |format=PDF |date= |accessdate=2009-09-25}}</ref> |
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| 10% |
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| JP |
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|- |
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| [[Ethylhexyl triazone|Uvinul T 150]] |
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| Octyl triazone, ethylhexyl triazone, EHT |
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| 5% (EU, AUS) 3% (JP)<sup>*</sup> |
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| EU, AUS |
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|- |
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| [[Diethylamino hydroxybenzoyl hexyl benzoate|Uvinul A Plus]] |
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| Diethylamino Hydroxybenzoyl Hexyl Benzoate |
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| 10% (EU, JP) |
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| EU, JP |
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|- |
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| [[Iscotrizinol|Uvasorb HEB]] |
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| Iscotrizinol, Diethylhexyl butamido triazone, DBT |
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| 10% (EU) 5% (JP)<sup>*</sup> |
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| EU, JP |
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|- |
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| [[Polysilicone-15|Parsol SLX]] |
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| Dimethico-diethylbenzalmalonate, Polysilicone-15 |
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| 10% |
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| EU, AUS, JP |
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|- |
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| [[Amiloxate]] |
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| Isopentyl-4-methoxycinnamate, Isoamyl p-Methoxycinnamate, IMC, Neo Heliopan E1000 |
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| 10%<sup>*</sup> |
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| EU, AUS |
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|} |
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<sup>*</sup> Time and Extent Application (TEA), Proposed Rule on FDA approval originally expected 2009, now expected 2015. |
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Many of the ingredients awaiting approval by the FDA were relatively new, and developed to absorb UVA.<ref>{{cite journal |first=Beth |last=Kapes |url=http://www.modernmedicine.com/modernmedicine/article/articleDetail.jsp?id=169626 |title=Docs rally for better sun protection — Advances still unavailable in United States |journal=Dermatology Times |volume=26 |issue=7 |page=100 |date=July 2005 |accessdate=July 23, 2014}}</ref> The 2014 [[Sunscreen Innovation Act]] was passed to accelerate the FDA approval process.<ref>{{cite web |url=https://www.congress.gov/bill/113th-congress/senate-bill/2141/all-actions |title=Sunscreen Innovation Act |publisher=United States Congress |accessdate=January 5, 2015}}</ref><ref>{{cite news |last=Sifferlin |first=Alexandra |title=We're One Step Closer to Better Sunscreen |url=http://time.com/2992200/were-one-step-closer-to-better-sunscreen/ |magazine=Time |date=July 16, 2014 |accessdate=August 1, 2014}}</ref> |
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== Application == |
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The dose used in FDA sunscreen testing is 2 mg/cm<sup>2</sup> of exposed skin.<ref name= CTFA1998>{{cite web | url=http://www.fda.gov/ohrms/dockets/dailys/00/Sep00/090600/c000573_10_Attachment_F.pdf | title=Re: Tentative Final Monograph for OTC Sunscreen | first=E. Edward |last=Kavanaugh | publisher=Cosmetic, Toiletry, and Fragrance Association | date=1998-09-11 | accessdate=2009-09-25}}</ref> If one assumes an "average" adult build of height 5 ft 4 in (163 cm) and weight 150 lb (68 kg) with a 32-inch (82-cm) waist, that adult wearing a bathing suit covering the groin area should apply approximately 30 g (or 30 ml, approximately 1 oz) evenly to the uncovered body area. This can be more easily thought of as a "golf ball" size amount of product per body, or at least six teaspoonfuls. Larger or smaller individuals should scale these quantities accordingly.<ref>{{cite web |url=http://www.thefactsabout.co.uk/how-and-why-we-use-sunscreen/content/239 |title=How and why we use sunscreen |publisher=Cosmetic, Toiletry & Perfumery Association |accessdate=May 11, 2016}}</ref> Considering only the face, this translates to about 1/4 to 1/3 of a teaspoon for the average adult face. |
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Some studies have shown that people commonly apply only 1/4 to 1/2 of the amount recommended for achieving the rated sun protection factor (SPF), and in consequence the effective SPF should be downgraded to a square root or 4th root of the advertised value.<ref name=squared>{{cite journal |vauthors=Faurschou A, Wulf HC | title=The relation between sun protection factor and amount of sunscreen applied in vivo | journal=Br. J. Dermatol. | volume=156 | issue=4 | pages=716–9 |date=April 2007 | pmid=17493070 | doi=10.1111/j.1365-2133.2006.07684.x | url=}}</ref> A later study found a significant exponential relation between SPF and the amount of sunscreen applied, and the results are closer to linearity than expected by theory.<ref name="DOI10.1111/j.1600-0781.2009.00408.x">{{cite journal |vauthors=Schalka S, dos Reis VM, Cucé LC | title=The influence of the amount of sunscreen applied and its sun protection factor (SPF): evaluation of two sunscreens including the same ingredients at different concentrations | journal=Photodermatol Photoimmunol Photomed | volume=25 | issue=4 | pages=175–80 |date=August 2009 | pmid=19614894 | doi=10.1111/j.1600-0781.2009.00408.x | url=}}</ref> |
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== Regulation == |
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{{Expand section|date=January 2018}} |
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;United States |
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Sunscreen labeling standards have been evolving in the United States since the FDA first adopted the SPF calculation in 1978.<ref>{{cite journal |url=http://www.fda.gov/downloads/Drugs/DevelopmentApprovalProcess/DevelopmentResources/Over-the-CounterOTCDrugs/StatusofOTCRulemakings/ucm090127.pdf |title=Sunscreen Drug Products for Over-the-Counter Human Use |journal=[[Federal Register]] |author=Department of Health and Human Services: Food and Drug Administration |volume=43 |issue=166 |pages=38206–38269 |date=August 25, 1978 |accessdate=July 30, 2014}}</ref> The FDA issued a comprehensive set of rules in June 2011, taking effect in 2012–2013, designed to help consumers identify and select suitable sunscreen products offering protection from sunburn, early skin aging, and skin cancer:<ref name="fda2011" /><ref>{{cite journal|title=Sunscreen Drug Products for Over-the-Counter Human Use; Final Rules and Proposed Rules|journal=Federal Register|date=June 17, 2011|volume=76|issue=117|pages=35620–35665|url=http://www.gpo.gov/fdsys/pkg/FR-2011-06-17/pdf/2011-14766.pdf|accessdate=August 19, 2014|author=Department of Health and Human Services: Food and Drug Administration}}</ref><ref>{{cite journal |title=Sunscreen Drug Products for Over-the-Counter Human Use; Delay of Compliance Dates |journal=Federal Register |date=May 11, 2012 |volume=77 |issue=92 |pages=27591–27593 |url=http://www.gpo.gov/fdsys/pkg/FR-2012-05-11/pdf/2012-11390.pdf |accessdate=September 27, 2012 |author=Department of Health and Human Services: Food and Drug Administration}}</ref> |
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* To be classified as "broad spectrum", sunscreen products must provide protection against both [[Ultraviolet A|UVA]] and [[UVB]], with specific tests required for both. |
* To be classified as "broad spectrum", sunscreen products must provide protection against both [[Ultraviolet A|UVA]] and [[UVB]], with specific tests required for both. |
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* Claims of products being "[[waterproof]]" or "sweatproof" are prohibited, while "sunblock" and "instant protection" and "protection for more than 2 hours" are all prohibited without specific FDA approval. |
* Claims of products being "[[waterproof]]" or "sweatproof" are prohibited, while "sunblock" and "instant protection" and "protection for more than 2 hours" are all prohibited without specific FDA approval. |
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| Line 347: | Line 24: | ||
* Sunscreens must include standardized "Drug Facts" information on the container. However, there is no regulation that deems it necessary to mention whether the contents contain [[nanoparticles]] of mineral ingredients. (The EU has stricter regulation against the use of nanoparticles, and in 2009 introduced labeling requirements for nanoparticle ingredients in certain sunscreens and cosmetics.)<ref>{{cite journal |url=http://eluxemagazine.com/magazine/is-sunscreen-safe |archive-url=https://web.archive.org/web/20150404221348/http://eluxemagazine.com/magazine/is-sunscreen-safe/ |title=Is Sunscreen Safe? |magazine=Eluxe |date=June 8, 2014 |archivedate=April 4, 2015 |deadurl=unfit}}</ref> |
* Sunscreens must include standardized "Drug Facts" information on the container. However, there is no regulation that deems it necessary to mention whether the contents contain [[nanoparticles]] of mineral ingredients. (The EU has stricter regulation against the use of nanoparticles, and in 2009 introduced labeling requirements for nanoparticle ingredients in certain sunscreens and cosmetics.)<ref>{{cite journal |url=http://eluxemagazine.com/magazine/is-sunscreen-safe |archive-url=https://web.archive.org/web/20150404221348/http://eluxemagazine.com/magazine/is-sunscreen-safe/ |title=Is Sunscreen Safe? |magazine=Eluxe |date=June 8, 2014 |archivedate=April 4, 2015 |deadurl=unfit}}</ref> |
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== Environmental effects ==https://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeg |
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== Environmental effects == |
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Certain sunscreens in water under ultraviolet light can increase the production of [[hydrogen peroxide]], which damages [[phytoplankton]].<ref name=San2014/> Oxybenzone damages [[coral]].<ref>{{cite news|last1=Worl|first1=Justin|title=How Sunscreen May Be Destroying Coral Reefs|url=http://time.com/4080985/sunscreen-coral-reefs/|accessdate=5 December 2016|work=TIME.com}}</ref> Nanoparticles of titanium dioxide, an ingredient in some sunscreens, can accumulate in coastal waters and be ingested by marine animals.<ref name=San2014>{{cite journal |author1=Sánchez-Quiles D. |author2=Tovar-Sánchez A. |title=Sunscreens as a source of hydrogen peroxide production in coastal waters |journal=Environ Sci Technol |volume=48 |issue=16 |pages=9037–9042 |year=2014 |pmid=25069004 |doi=10.1021/es5020696 |bibcode=2014EnST...48.9037S }}</ref> |
Certain sunscreens in water under ultraviolet light can increase the production of [[hydrogen peroxide]], which damages [[phytoplankton]].<ref name=San2014/> Oxybenzone damages [[coral]].<ref>{{cite news|last1=Worl|first1=Justin|title=How Sunscreen May Be Destroying Coral Reefs|url=http://time.com/4080985/sunscreen-coral-reefs/|accessdate=5 December 2016|work=TIME.com}}</ref> Nanoparticles of titanium dioxide, an ingredient in some sunscreens, can accumulate in coastal waters and be ingested by marine animals.<ref name=San2014>{{cite journal |author1=Sánchez-Quiles D. |author2=Tovar-Sánchez A. |title=Sunscreens as a source of hydrogen peroxide production in coastal waters |journal=Environ Sci Technol |volume=48 |issue=16 |pages=9037–9042 |year=2014 |pmid=25069004 |doi=10.1021/es5020696 |bibcode=2014EnST...48.9037S }}</ref> |
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Revision as of 07:06, 18 June 2018
| Sunscreen | |
|---|---|
 Sunscreen on back under normal and UV light | |
| Other names | Sun screen, sunblock, suntan lotion, sunburn cream, sun cream, block out[1] |
https://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpegabeling standards have been evolving in the United States since the FDA first adopted the SPF calculation in 1978.[2] The FDA issued a comprehensive set of rules in June 2011, taking effect in 2012–2013, designed to help consumers identify and select suitable sunscreen products offering protection from sunburn, early skin aging, and skin cancer:[3][4][5]
- To be classified as "broad spectrum", sunscreen products must provide protection against both UVA and UVB, with specific tests required for both.
- Claims of products being "waterproof" or "sweatproof" are prohibited, while "sunblock" and "instant protection" and "protection for more than 2 hours" are all prohibited without specific FDA approval.
- "Water resistance" claims on the front label must indicate how long the sunscreen remains effective and specify whether this applies to swimming or sweating, based on standard testing.
- Sunscreens must include standardized "Drug Facts" information on the container. However, there is no regulation that deems it necessary to mention whether the contents contain nanoparticles of mineral ingredients. (The EU has stricter regulation against the use of nanoparticles, and in 2009 introduced labeling requirements for nanoparticle ingredients in certain sunscreens and cosmetics.)[6]
== Environmental effects ==https://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeghttps://target.scene7.com/is/image/Target/15399556_Alt01?wid=488&hei=488&fmt=pjpeg Certain sunscreens in water under ultraviolet light can increase the production of hydrogen peroxide, which damages phytoplankton.[7] Oxybenzone damages coral.[8] Nanoparticles of titanium dioxide, an ingredient in some sunscreens, can accumulate in coastal waters and be ingested by marine animals.[7]
History
Early civilizations used a variety of plant products to help protect the skin from sun damage. For example, ancient Greeks used olive oil for this purpose, and ancient Egyptians used extracts of rice, jasmine, and lupine plants whose products are still used in skin care today.[9] Zinc oxide paste has also been popular for skin protection for thousands of years.[10]
Early synthetic sunscreens were first used in 1928.[9] The first major commercial product was brought to market in 1936, introduced by the founder of L'Oreal, French chemist Eugène Schueller.[11]
Among widely used modern sunscreens, one of the earliest was produced in 1944 for the US military by Benjamin Green, an airman and later a pharmacist, as the hazards of sun overexposure became apparent to soldiers in the Pacific tropics at the height of World War II.[12][11][13][14] The product, named Red Vet Pet (for red veterinary petrolatum), had limited effectiveness, working as a physical blocker of ultraviolet radiation. It was a disagreeable red, sticky substance similar to petroleum jelly. Sales boomed when Coppertone improved and commercialized the substance under the Coppertone girl and Bain de Soleil branding in the early 1950s.
In 1946, Swiss chemist Franz Greiter introduced what may have been the first effective modern sunscreen. The product, called Gletscher Crème (Glacier Cream), subsequently became the basis for the company Piz Buin, which is still today a marketer of sunscreen products, named in honor of the mountain where Greiter allegedly received the sunburn that inspired his concoction.[15][16][17] In 1974, Greiter adapted earlier calculations from Friedrich Ellinger and Rudolf Schulze and introduced the "sun protection factor" (SPF), which has become a worldwide standard for measuring the effectiveness of sunscreen.[12][18] It has been estimated that Gletscher Crème had an SPF of 2.
Water-resistant sunscreens were introduced in 1977,[11] and recent development efforts have focused on overcoming later concerns by making sunscreen protection both longer-lasting and broader-spectrum, as well as more appealing to use.[12]
Research
New products are in development such as sunscreens based on bioadhesive nanoparticles. These function by encapsulating commercially used UV filters, while being not only adherent to the skin but also non-penetrant. This strategy inhibits primary UV-induced damage as well as secondary free radicals.[19]
Notes
- ^ "Preventing melanoma". Cancer Research UK. Archived from the original on May 22, 2008. Retrieved September 22, 2009.
{{cite web}}: Unknown parameter|deadurl=ignored (|url-status=suggested) (help) - ^ Department of Health and Human Services: Food and Drug Administration (August 25, 1978). "Sunscreen Drug Products for Over-the-Counter Human Use" (PDF). Federal Register. 43 (166): 38206–38269. Retrieved July 30, 2014.
- ^ Cite error: The named reference
fda2011was invoked but never defined (see the help page). - ^ Department of Health and Human Services: Food and Drug Administration (June 17, 2011). "Sunscreen Drug Products for Over-the-Counter Human Use; Final Rules and Proposed Rules" (PDF). Federal Register. 76 (117): 35620–35665. Retrieved August 19, 2014.
- ^ Department of Health and Human Services: Food and Drug Administration (May 11, 2012). "Sunscreen Drug Products for Over-the-Counter Human Use; Delay of Compliance Dates" (PDF). Federal Register. 77 (92): 27591–27593. Retrieved September 27, 2012.
- ^ "Is Sunscreen Safe?". Eluxe. June 8, 2014. Archived from the original on April 4, 2015.
{{cite journal}}: Unknown parameter|deadurl=ignored (|url-status=suggested) (help) - ^ a b Sánchez-Quiles D.; Tovar-Sánchez A. (2014). "Sunscreens as a source of hydrogen peroxide production in coastal waters". Environ Sci Technol. 48 (16): 9037–9042. Bibcode:2014EnST...48.9037S. doi:10.1021/es5020696. PMID 25069004.
- ^ Worl, Justin. "How Sunscreen May Be Destroying Coral Reefs". TIME.com. Retrieved December 5, 2016.
- ^ a b Nadim, Shaath (2005). "Sunscreen Evolution". In Shaath, Nadim (ed.). Sunscreens : regulations and commercial development (3 ed.). Boca Raton, Fl.: Taylor & Francis. ISBN 978-0824757946.
- ^ Craddock, P.T. (1998). 2000 Years of Zinc and Brass. British Museum. p. 27. ISBN 0-86159-124-0.
- ^ a b c Rigel, Darrell S. (2004). Photoaging. Hoboken: Informa Healthcare. pp. 73–74. ISBN 9780824752095.
- ^ a b c Lim, Henry W. "Quantum Leaps: New, Improved Sunscreens Have Arrived". The Skin Cancer Foundation. Archived from the original on April 14, 2012.
{{cite web}}: Unknown parameter|deadurl=ignored (|url-status=suggested) (help) - ^ Wang, Steven Q; Hu, Judy Y. "Challenges in Making an Effective Sunscreen". The Skin Cancer Foundation. Retrieved June 12, 2014.
- ^ MacEachern, W.N.; Jillson, O.F. (January 1964). "A Practical Sunscreen — "Red Vet Pet"". Arch Dermatol. 89 (1): 147–150. doi:10.1001/archderm.1964.01590250153027. PMID 14070829. Retrieved July 24, 2014.
- ^ Shaath, Nadim A., editor (2005). Sunscreens: Regulations and Commercial Development, Third Edition. Taylor & Francis Group.
{{cite book}}:|first=has generic name (help)CS1 maint: multiple names: authors list (link) - ^ "Sunscreen: A History". The New York Times. June 23, 2010. Retrieved July 24, 2014.
- ^ "Gletscher Crème". 2010-04-22. Piz Buin. Archived from the original on May 12, 2010. Retrieved June 29, 2013.
- ^ Lim, Henry W.; et al., eds. (2007). Photodermatology. CRC Press. p. 6. ISBN 9781420019964. Retrieved July 24, 2014.
- ^ Deng, Yang; Ediriwickrema, Asiri; Yang, Fan; Lewis, Julia; Girardi, Michael; Saltzman, W. Mark. "A sunblock based on bioadhesive nanoparticles". Nature Materials. 14 (12): 1278–1285. Bibcode:2015NatMa..14.1278D. doi:10.1038/nmat4422. PMC 4654636. PMID 26413985.