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Undid revision 220649522 by Darius Sinclair (talk) suntan lotion is NOT sunblock in US
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{{Mergefrom|Sunscreen controversy|date=April 2008}}
{{Mergefrom|Sunscreen controversy|date=April 2008}}
{{POV|date=April 2008}}
{{POV|date=April 2008}}
'''Sunscreen''' (also known as '''sunblock''' or '''sun tan lotion''') is a [[lotion]], spray or other [[topical]] product that absorbs or reflects the [[sun]]'s [[ultraviolet]] (UV) radiation, and protects the [[skin]]. Medical organizations such as the American Cancer Society recommend the use of sunscreen,<ref>[http://www.cancer.org/docroot/PED/content/ped_7_1_What_You_Need_To_Know_About_Skin_Cancer.asp] What You Need To Know About Skin Cancer</ref> despite many epidemiological studies indicating an increased melanoma risk for the sunscreen user.<ref name=Garland>{{cite journal |author=Garland C, Garland F, Gorham E |title=Could sunscreens increase melanoma risk? |url= http://www.ajph.org/cgi/reprint/82/4/614 |journal=Am J Public Health |volume=82 |issue=4 |pages=614–5 |year=1992 |pmid=1546792 |issn=}}</ref><ref name=Westerdahl2000> {{cite journal |author=Westerdahl J; Ingvar C; Masback A; Olsson H |title= Sunscreen use and malignant melanoma. | journal= International journal of cancer. Journal international du cancer |volume=87 |pages=145–50 |year=2000 |doi= 10.1002/1097-0215(20000701)87:1<145::AID-IJC22>3.0.CO;2-3 }}</ref><ref name=Autier> {{cite journal |author=Autier P; Dore J F; Schifflers E; et al |title=Melanoma and use of sunscreens: An EORTC case control study in Germany, Belgium and France |url= |journal=Int. J. Cancer |volume=61 |issue= |pages=749–755 |year=1995 |pmid= |issn= |doi=10.1002/ijc.2910610602}}</ref><ref name=Weinstock> {{cite journal |author=Weinstock, M. A. |title=Do sunscreens increase or decrease melanoma risk: An epidemiologic evaluation. |url= |journal=Journal of Investigative Dermatology Symposium Proceedings |volume=4 |issue= |pages= 97–100 |year=1999 |issn= |doi=10.1038/sj.jidsp.}}</ref><ref name=Vainio> {{cite journal |author=Vainio, H., Bianchini, F. |title=Cancer-preventive effects of sunscreens are uncertain. |url= |journal=Scandinavian Journal of Work Environment and Health |volume=26 |issue= |pages=529–31 |year=2000 |issn=}}</ref><ref name=Wolf1998> {{cite journal |author=Wolf P, Quehenberger F, Müllegger R, Stranz B, Kerl H. |title=Phenotypic markers, sunlight-related factors and sunscreen use in patients with cutaneous melanoma: an Austrian case-control study. |url= |journal=Melanoma Res. |volume=8 |issue=4 |pages=370–378 |year=1998 |pmid=9764814 |issn= |doi=10.1097/00008390-199808000-00012}}</ref><ref name=Graham> {{cite journal |author=Graham S, Marshall J, Haughey B, Stoll H, Zielezny M, Brasure J, West D. |title=An inquiry into the epidemiology of melanoma. |url= http://www.ncbi.nlm.nih.gov.ezproxy.its.uu.se/sites/entrez |journal=Am J Epidemiol. |volume=122 |issue=4 |pages=606–619 |year=1985 |pmid= |issn=}}</ref><ref name=Beitner1990> {{cite journal |author=Beitner H, Norell SE, Ringborg U, Wennersten G, Mattson B. |title=Malignant melanoma: aetiological importance of individual pigmentation and sun exposure. |url= http://www.ncbi.nlm.nih.gov.ezproxy.its.uu.se/pubmed/2297503?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum |journal=Br J Dermatol.|volume=122 |issue=1 |pages=43–51 |year=1990 |pmid=2297503 |issn= |doi=10.1111/j.1365-2133.1990.tb08238.x}}</ref> (see [[sunscreen controversy]] for a discussion of possible reasons)
'''Sunscreen''' (also known as '''sunblock''' ''(US)'' or '''sun tan lotion''' ''(UK)'') is a [[lotion]], spray or other [[topical]] product that absorbs or reflects the [[sun]]'s [[ultraviolet]] (UV) radiation, and protects the [[skin]]. Medical organizations such as the American Cancer Society recommend the use of sunscreen,<ref>[http://www.cancer.org/docroot/PED/content/ped_7_1_What_You_Need_To_Know_About_Skin_Cancer.asp] What You Need To Know About Skin Cancer</ref> despite many epidemiological studies indicating an increased melanoma risk for the sunscreen user.<ref name=Garland>{{cite journal |author=Garland C, Garland F, Gorham E |title=Could sunscreens increase melanoma risk? |url= http://www.ajph.org/cgi/reprint/82/4/614 |journal=Am J Public Health |volume=82 |issue=4 |pages=614–5 |year=1992 |pmid=1546792 |issn=}}</ref><ref name=Westerdahl2000> {{cite journal |author=Westerdahl J; Ingvar C; Masback A; Olsson H |title= Sunscreen use and malignant melanoma. | journal= International journal of cancer. Journal international du cancer |volume=87 |pages=145–50 |year=2000 |doi= 10.1002/1097-0215(20000701)87:1<145::AID-IJC22>3.0.CO;2-3 }}</ref><ref name=Autier> {{cite journal |author=Autier P; Dore J F; Schifflers E; et al |title=Melanoma and use of sunscreens: An EORTC case control study in Germany, Belgium and France |url= |journal=Int. J. Cancer |volume=61 |issue= |pages=749–755 |year=1995 |pmid= |issn= |doi=10.1002/ijc.2910610602}}</ref><ref name=Weinstock> {{cite journal |author=Weinstock, M. A. |title=Do sunscreens increase or decrease melanoma risk: An epidemiologic evaluation. |url= |journal=Journal of Investigative Dermatology Symposium Proceedings |volume=4 |issue= |pages= 97–100 |year=1999 |issn= |doi=10.1038/sj.jidsp.}}</ref><ref name=Vainio> {{cite journal |author=Vainio, H., Bianchini, F. |title=Cancer-preventive effects of sunscreens are uncertain. |url= |journal=Scandinavian Journal of Work Environment and Health |volume=26 |issue= |pages=529–31 |year=2000 |issn=}}</ref><ref name=Wolf1998> {{cite journal |author=Wolf P, Quehenberger F, Müllegger R, Stranz B, Kerl H. |title=Phenotypic markers, sunlight-related factors and sunscreen use in patients with cutaneous melanoma: an Austrian case-control study. |url= |journal=Melanoma Res. |volume=8 |issue=4 |pages=370–378 |year=1998 |pmid=9764814 |issn= |doi=10.1097/00008390-199808000-00012}}</ref><ref name=Graham> {{cite journal |author=Graham S, Marshall J, Haughey B, Stoll H, Zielezny M, Brasure J, West D. |title=An inquiry into the epidemiology of melanoma. |url= http://www.ncbi.nlm.nih.gov.ezproxy.its.uu.se/sites/entrez |journal=Am J Epidemiol. |volume=122 |issue=4 |pages=606–619 |year=1985 |pmid= |issn=}}</ref><ref name=Beitner1990> {{cite journal |author=Beitner H, Norell SE, Ringborg U, Wennersten G, Mattson B. |title=Malignant melanoma: aetiological importance of individual pigmentation and sun exposure. |url= http://www.ncbi.nlm.nih.gov.ezproxy.its.uu.se/pubmed/2297503?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum |journal=Br J Dermatol.|volume=122 |issue=1 |pages=43–51 |year=1990 |pmid=2297503 |issn= |doi=10.1111/j.1365-2133.1990.tb08238.x}}</ref> (see [[sunscreen controversy]] for a discussion of possible reasons)


Sunscreens contain one or more UV filters of which there are three main types<ref>Shaath, N. (2005). "The Chemistry of Ultraviolet Filters," in Regulations and Commericial Development 3rd edition, edited by N. Shaath, Taylor and Francis Press, New York. 954pp, 2005.</ref> :
Sunscreens contain one or more UV filters of which there are three main types<ref>Shaath, N. (2005). "The Chemistry of Ultraviolet Filters," in Regulations and Commericial Development 3rd edition, edited by N. Shaath, Taylor and Francis Press, New York. 954pp, 2005.</ref> :

Revision as of 22:00, 20 June 2008

Sunscreen (also known as sunblock (US) or sun tan lotion (UK)) is a lotion, spray or other topical product that absorbs or reflects the sun's ultraviolet (UV) radiation, and protects the skin. Medical organizations such as the American Cancer Society recommend the use of sunscreen,[1] despite many epidemiological studies indicating an increased melanoma risk for the sunscreen user.[2][3][4][5][6][7][8][9] (see sunscreen controversy for a discussion of possible reasons)

Sunscreens contain one or more UV filters of which there are three main types[10] :

Dosing

The dose used in FDA sunscreen testing is 2 mg/cm² of exposed skin.[11] Provided one assumes an "average" adult build of height 5 ft 4 in (163 cm) and weight 150 lb (68 kg) with a 32 in (82 cm) waist, that adult wearing a bathing suit covering the groin area should apply 29 g (approximately 1 oz) evenly to the uncovered body area. Considering only the face, this translates to about 1/4 to 1/3 of a teaspoon for the average adult face.

Contrary to the common advice that sunscreen should be reapplied every 2–3 hours, some research has shown that the best protection is achieved by application 15–30 minutes before exposure, followed by one reapplication 15–30 minutes after the sun exposure begins. Further reapplication is only necessary after activities such as swimming, sweating, and rubbing.[12]

However, more recent research at the University of California, Riverside indicates that sunscreen needs to be reapplied within 2 hours in order to remain effective. Not reapplying could even cause more cell damage than not using sunscreen at all, due to the release of extra free radicals from those sunscreen chemicals which were absorbed into the skin.[13]

History

The first effective sunscreen may have been developed by chemist Franz Greiter in 1938. The product, called Gletscher Crème (Glacier Cream), subsequently became the basis for the company Piz Buin (named in honor of the place Greiter allegedly obtained the sunburn that inspired his concoction), which today is a well-known marketer of sunscreen products. Some internet articles suggest that Gletscher Crème had a sun protection factor of 2, although a research citation is not readily available online.

The first widely used sunscreen was produced by Benjamin Greene, an airman and later a pharmacist, in 1944. The product, 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. This product was developed during the height of World War II, when it was likely that the hazards of sun overexposure were becoming apparent to soldiers in the Pacific and to their families at home.

Franz Greiter is credited with introducing the concept of Sun Protection Factor (SPF) in 1962, which has become a worldwide standard for measuring the effectiveness of sunscreen when applied at an even rate of 2 milligrams per square centimeter (mg/cm2). Some controversy exists over the usefulness of SPF measurements, especially whether the 2 mg/cm2 application rate is an accurate reflection of people’s actual use.

Newer sunscreens have been developed with the ability to withstand contact with water and sweat.

Measurements of sunscreen protection

Sunburn protection factor

The SPF of a sunscreen is a laboratory measure of the effectiveness of sunscreen; the higher the SPF, the more protection a sunscreen offers against UV-B (the ultraviolet radiation that causes sunburn). The SPF indicates the time a person can be exposed to sunlight before getting sunburn with a sunscreen applied relative to the time they can be exposed without sunscreen. For example, someone who would burn after 12 minutes in the sun would expect to burn after 120 minutes if protected by a sunscreen with SPF 10. In practice, the protection from a particular sunscreen depends on factors such as:

  • The skin type of the user.
  • The amount applied and frequency of re-application.
  • Activities in which one engages (for example, swimming leads to a loss of sunscreen from the skin).
  • Amount of sunscreen the skin has absorbed.

The SPF is an imperfect measure of skin damage because invisible damage and skin aging is also caused by the very common ultraviolet type A, which does not cause reddening or pain. Conventional sunscreen does not block UVA as effectively as it does UVB, and an SPF rating of 30+ may translate to significantly lower levels of UVA protection according to a 2003 study. According to a 2004 study, UVA also causes DNA damage to cells deep within the skin, increasing the risk of malignant melanomas.[14] Even some products labeled "broad-spectrum UVA/UVB protection" do not provide good protection against UVA rays.[15] The best UVA protection is provided by products that contain zinc oxide, avobenzone, and ecamsule. Titanium dioxide probably gives good protection, but does not completely cover the entire UV-A spectrum.[16]

Owing to consumer confusion over the real degree and duration of protection offered, labeling restrictions are in force in several countries. In the United States in 1999, the Food and Drug Administration (FDA) decided to institute the labelling of SPF 30+ for sunscreens offering more protection, and a similar restriction applies in Australia. This was done to discourage companies from making unrealistic claims about the level of protection offered (such as "all day protection"),[17]. In the EU sunscreens are limited to SPF 50+, indicating a SPF of 60 or higher.[18]

UV-B 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.

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 the UV-B range (290–350 nm), along with a table of how effective various wavelengths are in causing sunburn (the erythemal action spectrum) and the actual intensity spectrum of sunlight (see the figure). Such in vitro measurements agree very well with in vivo measurements.[19]

Mathematically, the SPF is calculated from measured data as

where is the solar irradiance spectrum, the erythemal action spectrum, and the monochromatic protection factor, all functions of the wavelength . The MPF is roughly the inverse of the transmittance at a given wavelength.

The above means that the SPF is not simply the inverse of the transmittance in the UV-B region. If that were true, then applying two layers of SPF 5 sunscreen would be equivalent to SPF 25 (5 times 5). The actual combined SPF is always lower than the square of the single-layer SPF.

Measurements of UVA protection

Persistent Pigment Darkening (PPD), Immediate Pigment Darkening (IPD), Boots Star System, Japanese PA system

The Persistent Pigment Darkening (PPD) method is a method of measuring UVA protection, similar to the SPF method of measuring UVB light protection. Originally developed in Japan, and is the preferred method used by manufacturers such as L'Oreal.

Instead of measuring erythema or reddening of the skin, the PPD method uses UVA radiation to cause a permanent darkening or tanning of the skin.Theoretically, a sunscreen with a PPD rating of 10 should allow you to endure 10 times as much UVA as you would without protection. The PPD method is an in vivo test like SPF. In addition Colipa has introduced a method which is claimed can measure this in vitro and provide parity with the PPD method

As part of revised guidelines for sunscreens in the EU, a requirement to provide the consumer with a minimum level of UVA protection in relation to the SPF. This should a UVA PF of at least 1/3 of the SPF to carry the UVA seal. The implementation of this seal is in its phase-in period, so a sunscreen without may already offer this protection.[20]

Star rating system

In the UK and Ireland, the Boots star rating system is a proprietary method used to describe the ratio of UVA to UVB protection offered by sun screen creams and sprays. Invented by Dr Diffey of the Boots Company in Nottingham UK, it has been adopted by most companies marketing these products in the UK. The logo and methodology of the test are freely licenced to any manufacturer or brand of sunscreens that wishes to place product on the UK market. It should not be confused with SPF which is measured with reference to burning and UVB. One star products provide the least ratio of UVA protection, five star products are the best. The method has recently been revised in light of the Colipa UVA PF test, and with the new EU recommendations regarding UVA PF. The method still uses a spectrophotometer to measure absorption of UVA vs 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 of photostability when the product is used

Active ingredients

The principal ingredients in sunscreens are usually aromatic molecules 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.[11] A chemical stabilizer is included in sunscreens containing avobenzone to slow breakdown.[citation needed]

Some sunscreens also include enzymes like photolyase, which are able to repair UV-damaged DNA.[21]

FDA allowable ingredients

The following are the FDA allowable active ingredients in sunscreens:

UV-filter other names maximum concentration permitted in these countries Results of safety testing
p-Aminobenzoic acid PABA 15% EC, USA, AUS Mixed[22][23][24]
Padimate O OD-PABA, octyldimethyl-PABA, σ-PABA 8% EC, USA, AUS not tested
Phenylbenzimidazole sulfonic acid Ensulizole, Eusolex 232, PBSA, Parsol HS 4%(US,AUS) 8%(EC) EC,USA, AUS Genotoxic in bacteria[25]
Cinoxate 2-Ethoxyethyl p-methoxycinnamate 3%(US) 6%(AUS) USA, AUS not tested
Dioxybenzone benzophenone-8 3% USA, AUS not tested
oxybenzone benzophenone-3, Eusolex 4360, Escalol 567 6%(US) 10%(AUS) EC, USA, AUS not tested
Homosalate Homomethyl salicylate, HMS 10%(EC) 15%(US,AUS) EC, USA, AUS not tested
Methyl anthranilate Methyl-aminobenzoate, meradimate 5% USA, AUS not tested
Octocrylene Eusolex OCR, 2-cyano-3,3diphenyl acrylic acid, 2-ethylhexylester 10% EC,USA, AUS Increases ROS
Octyl methoxycinnamate Octinoxate, EMC, OMC, Ethylmethoxycinnamate, Escalol 557, 2-ethylhexyl-paramethoxycinnamate, Parsol MCX 7.5%(US) 10%(EC,AUS) EC,USA, AUS Protects against skin tumors in mice[26]
Octyl salicylate Octisalate, 2-Ethylhexyl salicylate, Escalol 587, 5% EC,USA, AUS not tested
Sulisobenzone 2-Hydroxy-4-Methoxybenzophenone-5-sulfonic acid,

3-benzoyl-4-hydroxy-6-methoxybenzenesulfonic acid, BENZ-4, Escalol 577

5%(EC) 10%(US, AUS) EC,USA, AUS Protects against skin tumors in mice [26]
Trolamine salicylate Triethanolamine salicylate 12% USA, AUS not tested
Avobenzone 1-(4-methoxyphenyl)-3-(4-tert-butylphenyl)propane-1,3-dione, Butyl methoxy dibenzoylmethane, BMDBM, Parsol 1789, Eusolex 9020 3%(US) 5%(AUS) EC, USA, AUS Not available[27]
Ecamsule Mexoryl SX, Terephthalylidene Dicamphor Sulfonic Acid 10 EC, USA, AUS Protects against skin tumors in mice[28][29][30]
Titanium dioxide 25% EC,USA, AUS not tested
Zinc oxide 25%(US) 20%(AUS) (EC)Not listed as sunscreen, Still under SCCP review EC,USA, AUS Protects against skin tumors in mice[28][26]

Other ingredients approved within the EU[31] and other parts of the world:[32]

UV-filter other names maximum concentration permitted in Results of testing
4-Methylbenzylidene camphor Enzacamene, Parsol 5000, Eusolex 6300, MBC 4% EC, AUS not tested
Tinosorb M Bisoctrizole, Methylene Bis-Benzotriazolyl Tetramethylbutylphenol,MBBT 10% EC, AUS not tested
Tinosorb S Bis-ethylhexyloxyphenol methoxyphenol triazine, Bemotrizinol, BEMT, anisotriazine 10% EC, AUS not tested
Neo Heliopan AP Bisdisulizole Disodium, Disodium phenyl dibenzimidazole tetrasulfonate, bisimidazylate, DPDT 10% EC, AUS not tested
Mexoryl XL Drometrizole Trisiloxane 15% EC, AUS not tested
Uvinul T 150 Octyl triazone, ethylhexyl triazone, ET 5% EC, AUS not tested
Uvinul A Plus Diethylamino Hydroxybenzoyl Hexyl Benzoate 10% (EC) EC
Uvasorb HEB Iscotrizinol, Diethylhexyl butamido triazone, DBT 10% EC not tested
Parsol SLX Dimethico-diethylbenzalmalonate, Polysilicone-15 10% EC, AUS not tested
Isopentenyl-4-methoxycinnamate Isoamyl p-Methoxycinnamate, IMC, Neo Heliopan E1000, Amiloxate 10% EC, AUS not tested

Many of the ingredients not approved by the FDA are relatively new and developed to absorb UVA.[33]

Possible adverse effects

Main article: Sunscreen controversy

Adverse health effects may be associated with some synthetic compounds in sunscreens.[34]

See also

References

  1. ^ [1] What You Need To Know About Skin Cancer
  2. ^ Garland C, Garland F, Gorham E (1992). "Could sunscreens increase melanoma risk?". Am J Public Health. 82 (4): 614–5. PMID 1546792.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. ^ Westerdahl J; Ingvar C; Masback A; Olsson H (2000). "Sunscreen use and malignant melanoma". International journal of cancer. Journal international du cancer. 87: 145–50. doi:10.1002/1097-0215(20000701)87:1<145::AID-IJC22>3.0.CO;2-3.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ Autier P; Dore J F; Schifflers E; et al. (1995). "Melanoma and use of sunscreens: An EORTC case control study in Germany, Belgium and France". Int. J. Cancer. 61: 749–755. doi:10.1002/ijc.2910610602. {{cite journal}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  5. ^ Weinstock, M. A. (1999). "Do sunscreens increase or decrease melanoma risk: An epidemiologic evaluation". Journal of Investigative Dermatology Symposium Proceedings. 4: 97–100. doi:10.1038/sj.jidsp. {{cite journal}}: Check |doi= value (help)
  6. ^ Vainio, H., Bianchini, F. (2000). "Cancer-preventive effects of sunscreens are uncertain". Scandinavian Journal of Work Environment and Health. 26: 529–31.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ^ Wolf P, Quehenberger F, Müllegger R, Stranz B, Kerl H. (1998). "Phenotypic markers, sunlight-related factors and sunscreen use in patients with cutaneous melanoma: an Austrian case-control study". Melanoma Res. 8 (4): 370–378. doi:10.1097/00008390-199808000-00012. PMID 9764814.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ Graham S, Marshall J, Haughey B, Stoll H, Zielezny M, Brasure J, West D. (1985). "An inquiry into the epidemiology of melanoma". Am J Epidemiol. 122 (4): 606–619.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ Beitner H, Norell SE, Ringborg U, Wennersten G, Mattson B. (1990). "Malignant melanoma: aetiological importance of individual pigmentation and sun exposure". Br J Dermatol. 122 (1): 43–51. doi:10.1111/j.1365-2133.1990.tb08238.x. PMID 2297503.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ^ Shaath, N. (2005). "The Chemistry of Ultraviolet Filters," in Regulations and Commericial Development 3rd edition, edited by N. Shaath, Taylor and Francis Press, New York. 954pp, 2005.
  11. ^ a b http://www.fda.gov/ohrms/dockets/dailys/00/Sep00/090600/c000573_10_Attachment_F.pdf
  12. ^ Diffey B (2001). "When should sunscreen be reapplied?". J Am Acad Dermatol. 45 (6): 882–5. doi:10.1067/mjd.2001.117385. PMID 11712033.
  13. ^ Kerry M. Hanson, Enrico Gratton and Christopher J. Bardeen (2006). "Sunscreen enhancement of UV-induced reactive oxygen species in the skin". Free Radical Biology and Medicine. 11: 1205. doi:10.1016/j.freeradbiomed.2006.06.011.
  14. ^ Berneburg M, Plettenberg H, Medve-König K, Pfahlberg A, Gers-Barlag H, Gefeller O, Krutmann J (2004). "Induction of the photoaging-associated mitochondrial common deletion in vivo in normal human skin". J Invest Dermatol. 122 (5): 1277–83. doi:10.1111/j.0022-202X.2004.22502.x. PMID 15140232.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  15. ^ http://msnbc.msn.com/id/12081374/
  16. ^ http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&list_uids=10759815&dopt=medline
  17. ^ http://www.fda.gov/bbs/topics/ANSWERS/ANS00955.html
  18. ^ http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:265:0039:0043:EN:PDF
  19. ^ http://www.optometrics.com/corporate/support/KFDA.html
  20. ^ http://www.colipa.com/site/index.cfm?SID=15588&OBJ=26368&back=1
  21. ^ Dagmar Kulms, Birgit Pöppelmann, Daniel Yaroshdagger, Thomas A. Luger, Jean KrutmannDagger and Thomas Schwarz (1999). Nuclear and cell membrane effects contribute independently to the induction of apoptosis in human cells exposed to UVB radiation PNAS 96(14):7974-7979
  22. ^ H Flindt-Hansen (1990). "The inhibiting effect of PABA on photocarcinogenesis". Archives of Dermatological Research. 282: 38–41. doi:10.1007/BF00505643. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  23. ^ H Flindt-Hansen (1990). "The effect of short-term application of PABA on photocarcinogenesis". Acta Derm Venerol. 70: 72–75. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  24. ^ P. J. Osgood (1982). "The sensitization of near-ultraviolet radiation killing of mammalian cells by the sunscreen agent para-aminobenzoic acid". Journal of Investigative Dermatology. 79 (6): 354–357. doi:10.1111/1523-1747.ep12529409. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  25. ^ Mosley, C N; Wang, L; Gilley, S; Wang, S; Yu, H (2007). "Light-Induced Cytotoxicity and Genotoxicity of a Sunscreen Agent, 2-Phenylbenzimidazol in Salmonella typhimurium TA 102 and HaCaT Keratinocytes". International Journal of Environmental Research and Public Health. 4 (2): 126–131. {{cite journal}}: Cite has empty unknown parameter: |month= (help)CS1 maint: multiple names: authors list (link)
  26. ^ a b c Cite error: The named reference Nohynek2001 was invoked but never defined (see the help page).
  27. ^ Nash,JF (2006). "Human Safety and Efficacy of Ultraviolet Filters and Sunscreen Products". Dermatologic Clinics. 24: 35–51. doi:10.1016/j.det.2005.09.006.
  28. ^ a b Lautenschlager, Stephan; Wulf, Hans Christian; Pittelkow, Mark R. (2007). "photoprotection". Lancet. 370: 528–37. doi:10.1016/S0140-6736(07)60638-2.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  29. ^ Benech-Kieffer F, Meuling WJ, Leclerc C, Roza L, Leclaire J, Nohynek G (2003). "Percutaneous absorption of Mexoryl SX in human volunteers: comparison with in vitro data". Skin Pharmacol Appl Skin Physiol. 16(6): 343–55. doi:10.1159/000072929. PMID 14528058. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  30. ^ Fourtanier A (1996). "Mexoryl SX protects against solar-simulated UVR-induced photocarcinogenesis in mice". Photochem Photobiol. 64(4): 688–93. doi:10.1111/j.1751-1097.1996.tb03125.x. PMID 8863475. {{cite journal}}: Unknown parameter |month= ignored (help)
  31. ^ http://eur-lex.europa.eu/LexUriServ/site/en/consleg/1976/L/01976L0768-20060809-en.pdf
  32. ^ http://www.tga.gov.au/docs/pdf/argom_10.pdf
  33. ^ http://www.modernmedicine.com/modernmedicine/article/articleDetail.jsp?id=169626
  34. ^ http://www.straight.com/content.cfm?id=18501
* FDA monograph on sunscreen
* FDA monograph on dosing, mechanism of action, and photodegradation of sunscreen (PDF file)
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