DEET: Difference between revisions

{{short description|Chemical compound}}

{{cs1 config|name-list-style=vanc}}

{{For|the former Australian government department known as DEET|Department of Employment, Education and Training}}

{{distinguish|DDT}}

| Watchedfields = changed

| verifiedrevid = 460112045

| ImageSize =

| ImageFile1 = DEET Ball and Stick.png

| ImageSize1 = 185px

| PIN = ''N'',''N''-Diethyl-3-methylbenzamide

| OtherNames = ''N'',''N''-Diethyl-''m''-toluamide

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| KEGG_Ref = {{keggcite|correct|kegg}}

| ChEBI_Ref = {{ebicite|changed|EBI}}

| ChEBI = 7071

| ChEMBL = 1453317

| InChI = 1S/C12H17NO/c1-4-13(5-2)12(14)11-8-6-7-10(3)9-11/h6-9H,4-5H2,1-3H3

| PubChem = 4284

| SMILES = O=C(c1cc(ccc1)C)N(CC)CC

|Section2={{Chembox Properties

| Formula = C₁₂H₁₇NO

| MolarMass = 191.27 g/mol

| Appearance =

| Density = 0.998 g/mL

| MeltingPtC = -33

| BoilingPtC = 288 to 292

| BoilingPt_notes =

| Solubility =

|Section6={{Chembox Pharmacology

| ATCCode_prefix = P03

| ATCCode_suffix = BX02

| ATC_Supplemental = {{ATCvet|P53|GX01}}

}}

|Section7={{Chembox Hazards

| ExternalSDS = [http://msds.chem.ox.ac.uk/DI/N,N-diethyl-N-toluamide.html External MSDS]

| GHSPictograms = {{GHS07}}

| GHSSignalWord = '''DANGER'''

| HPhrases = {{H-phrases|302|315|319|402}}

| FlashPt =

| AutoignitionPt =

| NFPA-H = 2

| NFPA-F = 1

| NFPA-R = 0

| NFPA-S =

}}

'''''N'',''N''-Diethyl-''meta''-toluamide''', also called '''diethyltoluamide''' or '''DEET''' ({{IPAc-en|d|iː|t}}, from DET, the initials of di- + ethyl + toluamide),<ref>{{cite web |title=DEET |url=https://www.merriam-webster.com/dictionary/DEET |access-date=2023-06-04 |website=Merriam-Webster}}</ref><ref>{{Citation |last=Plumlee |first=Konnie H. |title=Chapter 21 - Insecticides and Molluscicides |date=2004-01-01 |url=https://www.sciencedirect.com/science/article/pii/B032301125X500248 |work=Clinical Veterinary Toxicology |pages=177–192 |editor-last=Plumlee |editor-first=Konnie H. |place=Saint Louis |publisher=Mosby |doi=10.1016/b0-32-301125-x/50024-8 |isbn=978-0-323-01125-9}}</ref> is the oldest, one of the most effective and most common active ingredient in commercial [[insect repellent]]s. It is a slightly yellow oil intended to be applied to the [[skin]] or to [[clothing]] and provides protection against [[mosquito]]es, flies, [[tick]]s, [[flea]]s, [[chiggers]], [[leeches]], and many other biting insects.

Unlike [[Icaridin]], DEET emits an odor that many find unpleasant, leaves skin greasy, dissolves plastics and synthetic fabrics<ref>{{cite web |title=Picaridin vs DEET: Which Is the Best Insect Repellent? |url=https://www.outdoors.org/resources/amc-outdoors/outdoor-resources/picaridin-vs-deet-which-is-the-best-insect-repellent/ |publisher=Appalachian Mountain Club |access-date=7 August 2023 |date=4 August 2023}}</ref> and interacts negatively with sunscreen.<ref name="cdcyb2024"/><ref name="jdt2016"/>

==Effectiveness==

DEET and [[icaridin]] are the most effective insect repellents available.<ref name=":3">{{cite journal|last=DeGennaro|first=Matthew|date=2015|title=The mysterious multi-modal repellency of DEET|journal=Fly|volume=9|issue=1|pages=45–51|doi=10.1080/19336934.2015.1079360|issn=1933-6942|pmc=4594586|pmid=26252744}}</ref> DEET is effective against a variety of invertebrates, including ticks, flies, mosquitos, and some parasitic worms.<ref name=":3" />

A 2018 systematic review found no consistent performance difference between DEET and [[icaridin]] in [[Field research|field studies]] and concluded that they are equally preferred mosquito repellents, noting that 50% DEET offers longer protection but is not available in some countries.<ref>{{cite journal |last1=Goodyer |first1=Larry |last2=Schofield |first2=Steven |date=2018-05-01 |title=Mosquito repellents for the traveller: does picaridin provide longer protection than DEET? |url=https://academic.oup.com/jtm/article/25/suppl_1/S10/4990399 |journal=Journal of Travel Medicine |language=en |volume=25 |issue=Suppl_1 |pages=S10–S15 |doi=10.1093/jtm/tay005 |pmid=29718433 |issn=1708-8305|doi-access=free }}</ref>

===Concentrations===

The concentration of DEET in products may range from less than 10% to nearly 100%, but concentrations greater than 50% do not increase the duration of protection.<ref>{{cite web |title=Mosquitoes, Ticks & Other Arthropods - CDC Yellow Book 2024 |url=https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods |access-date=2023-08-07 |publisher=Centers for Disease Control and Prevention}}</ref> Higher concentrations can be safely applied to clothing, although it may damage some types of synthetic fibers. In the United Kingdom, the publicly-funded healthcare system, the National Health Service (NHS), recommends that UK citizens should use a concentration of 50% when visiting areas of the world with malaria.<ref>{{cite web |last=Team |first=HPS Travel Health |title=Mosquito Bite Avoidance - Fit for Travel |url=https://www.fitfortravel.nhs.uk/advice/malaria/mosquito-bite-avoidance.aspx |access-date=2023-08-07 |website=www.fitfortravel.nhs.uk |language=en}}</ref> A lower concentration of 10% is recommended for infants and children.<ref>{{cite web |last=Canada |first=Health |date=2012-05-11 |title=Personal Insect repellents |url=https://www.canada.ca/en/health-canada/services/about-pesticides/insect-repellents.html |access-date=2023-08-07 |publisher=Government of Canada}}</ref><ref>American Academy of Pediatrics, “Summer Safety Tips,” Dec 2, 2017 https://www.healthychildren.org/English/safety-prevention/at-play/Pages/Summer-Safety-Tips-Staying-Safe-Outdoors.aspx</ref> [[Health Canada]] decided to limit DEET concentration to 30% in the country since 2002 due to an increased long-term risk observed with repeated applications.<ref>{{cite news |title=Health Canada to ban bug repellents with high concentrations of DEET |url=https://www.cbc.ca/news/canada/health-canada-to-ban-bug-repellents-with-high-concentrations-of-deet-1.320939 |access-date=7 August 2023 |work=CBC |date=24 April 2002}}</ref>

DEET is often sold and used in spray or lotion in concentrations up to 100%.<ref>{{CPID|id=594}}</ref> ''[[Consumer Reports]]'' found a direct [[correlation]] between DEET concentration and hours of protection against insect bites. 100% DEET was found to offer up to 12 hours of protection while several lower concentration DEET formulations (20–34%) offered 3–6 hours of protection.{{cn|date=July 2022}} Other research has corroborated the effectiveness of DEET.<ref name="Independent study: DEET products superior for fending off mosquito bites">{{cite press release | publisher = [[University of North Carolina at Chapel Hill|University of North Carolina]] | title = Independent study: DEET products superior for fending off mosquito bites | first = David | last = Williamson | date = 3 July 2002 | url = http://www.unc.edu/news/archives/jul02/fradin070202.htm | access-date = 19 May 2007 | archive-date = 30 June 2007 | archive-url = https://web.archive.org/web/20070630214005/http://www.unc.edu/news/archives/jul02/fradin070202.htm | url-status = dead }}</ref> The Centers for Disease Control and Prevention recommends 30–50% DEET to prevent the spread of pathogens carried by insects.<ref name = "CDC Travel">{{cite web | url = http://wwwn.cdc.gov/travel/yellowBookCh2-InsectsArthropods.aspx | title = Protection against Mosquitoes, Ticks, Fleas and Other Insects and Arthropods | work = Travelers' Health – Yellow Book | publisher = [[Centers for Disease Control and Prevention]] | date = 2009-02-05 | access-date = 2009-02-05 | archive-date = 2009-05-05 | archive-url = https://web.archive.org/web/20090505011906/http://wwwn.cdc.gov/travel/yellowBookCh2-InsectsArthropods.aspx | url-status = dead }}</ref>

A 2008 study found that higher concentrations of DEET have an improved ability to repel insects through fabric.<ref name="pmid18339904">{{cite journal| author=Ditzen M, Pellegrino M, Vosshall LB| title=Insect odorant receptors are molecular targets of the insect repellent DEET. | journal=Science | year= 2008 | volume= 319 | issue= 5871 | pages= 1838–42 | pmid=18339904 | doi=10.1126/science.1153121 | bibcode=2008Sci...319.1838D | s2cid=18499590 | url=https://pubmed.ncbi.nlm.nih.gov/18339904 }} </ref>

==Contraindications==

DEET should not be used on children younger than 2 months of age.<ref name="CDC"/>

==Adverse effects==

When used as directed, products containing between 10% and 30% DEET have been found by the [[American Academy of Pediatrics]] to be safe to use on children as well as adults.<ref name="CDC"/>

As a precaution, manufacturers advise that DEET products should not be used under clothing or on damaged skin, and that preparations be washed off after they are no longer needed or between applications.<ref name="CDC">{{cite web | url = https://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm | title = Insect Repellent Use and Safety | work = West Nile Virus | publisher = [[Centers for Disease Control and Prevention]] | date = 2007-01-12 | archive-url = https://web.archive.org/web/20130523154822/http://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm | archive-date = 23 May 2013 | url-status = dead }}</ref> DEET can irritate the eyes and, unlike [[icaridin]], it can cause breathing difficulty, [[headache]]s,<ref>{{cite web|url=https://www.nlm.nih.gov/medlineplus/ency/article/002763.htm |title=Bug spray poisoning |publisher= U.S. National Library of Medicine |date=October 2015 |access-date=2016-06-25}}</ref> or, in rare cases, it may cause severe [[epidermis (skin)|epidermal]] reactions.<ref name="CDC"/>

The authors of a 2002 study published in ''[[The New England Journal of Medicine]]'' wrote:<ref>{{cite journal | vauthors = Fradin MS, Day JF | title = Comparative efficacy of insect repellents against mosquito bites | journal = The New England Journal of Medicine | volume = 347 | issue = 1 | pages = 13–8 | date = July 2002 | pmid = 12097535 | doi = 10.1056/NEJMoa011699 | doi-access = free }}</ref>

<blockquote>... this repellent has been subjected to more scientific and toxicologic scrutiny than any other repellent substance. ... DEET has a remarkable safety profile after 40 years of use and nearly 8 billion human applications. Fewer than 50 cases of serious toxic effects have been documented in ... medical literature since 1960 ... Many of these cases of toxic effects involved long-term, heavy, frequent, or whole-body application of DEET. No correlation has been found between the concentration of DEET used and the risk of toxic effects. ... When applied with common sense, DEET-based repellents can be expected to provide a safe as well as a long-lasting repellent effect ... under circumstances in which it is crucial to be protected against arthropod bites that might transmit disease.</blockquote>

In the DEET Reregistration Eligibility Decision (RED) in 1998, the [[United States Environmental Protection Agency]] (EPA) reported 14 to 46 cases of potential DEET-associated [[seizure]]s, including four deaths. The EPA states: "... it does appear that some cases are likely related to DEET [[toxicity]]," which may underreport the risk as physicians may fail to check for history of DEET use or fail to report cases of seizure subsequent to DEET use.<ref>{{cite web|url=http://www.epa.gov/oppsrrd1/REDs/0002red.pdf |title=Reregistration Eligibility Decision: DEET |publisher=U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances |date=September 1998 |pages=39–40 |access-date=2012-09-08 |url-status=dead |archive-url=https://web.archive.org/web/20121021024248/http://www.epa.gov/oppsrrd1/REDs/0002red.pdf |archive-date=October 21, 2012 }}</ref>

In 1997, the Pesticide Information Project of Cooperative Extension Offices of [[Cornell University]] stated that "[[Everglades National Park]] employees having extensive DEET exposure were more likely to have [[insomnia]], mood disturbances and impaired [[cognitive function]] than lesser exposed co-workers".<ref name="EXTOXNET">{{cite web | publisher = EXTOXNET | work = Pesticide Information Profile | title = DEET | date = October 1997 | url = http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/deet-ext.html | access-date = 2007-09-26 | archive-url = https://web.archive.org/web/20201119060336/http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/deet-ext.html | archive-date = 2020-11-19 |url-status=dead }}</ref>

Citing human health reasons, [[Health Canada]] barred the sale of insect repellents for human use that contained more than 30% DEET in a 2002 re-evaluation "based on a human health risk assessment that considered daily application of DEET over a prolonged period of time". The agency recommended that DEET-based products be used on children between the ages of 2 and 12 only if the [[concentration]] of DEET is 10% or less and that repellents be applied no more than 3 times a day, children under 2 should not receive more than 1 application of repellent in a day and DEET-based products of any concentration should not be used on infants under 6 months.<ref>{{cite web |publisher=[[Health Canada]] |work=Healthy Living |title=Insect Repellents |date=August 2009 |url=http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/life-vie/insect-eng.php |access-date=2010-07-09 |url-status=dead |archive-url=https://web.archive.org/web/20100411092758/http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/life-vie/insect-eng.php |archive-date=2010-04-11 }}</ref><ref>{{cite web | publisher = [[Health Canada]] | work = Consumer Product Safety | title = Re-evaluation Decision Document: Personal insect repellents containing DEET (N,N-diethyl-m-toluamide and related compounds) | date = 2002-04-15 | url =http://publications.gc.ca/collections/Collection/H113-12-2002-1E.pdf | access-date = 2010-07-09 |archive-url=https://web.archive.org/web/20210304125828/https://publications.gc.ca/collections/Collection/H113-12-2002-1E.pdf |archive-date=4 March 2021}}</ref>

A 2020 study performed by students within the [[University of Florida]]'s College of Public Health and Health Professions analyzed data from the National Health and Nutrition Examination Survey and identified 1,205 participants who had "DEET metabolic levels recorded at or above detection limits". They analyzed [[biomarker]]s related to systemic inflammation, immune, liver, and kidney functions, and found no "evidence that DEET exposure has any impact on the biomarkers identified."<ref name="pmid32458781">{{cite journal| author=Haleem ZM, Yadav S, Cushion ML, Tanner RJ, Carek PJ, Mainous AG| title=Exposure to N,N-Diethyl-Meta-Toluamide Insect Repellent and Human Health Markers: Population Based Estimates from the National Health and Nutrition Examination Survey. | journal=Am J Trop Med Hyg | year= 2020 | volume= 103 | issue= 2 | pages= 812–814 | pmid=32458781 | doi=10.4269/ajtmh.20-0226 | pmc=7410448 }} </ref>

=== Detection in body fluids ===

DEET may be measured in blood, plasma, or urine by gas or liquid chromatography-mass spectrometry to confirm a diagnosis of poisoning in hospitalized patients or to provide evidence in a medicolegal death investigation. Blood or plasma DEET concentrations are expected to be in a range of 0.3–3.0&nbsp;mg/L during the first 8 hours after dermal application in persons using the chemical appropriately, >6&nbsp;mg/L in intoxicated patients and >100&nbsp;mg/L in victims of acute intentional oral overdose.<ref>{{cite journal | vauthors = Tenenbein M | title = Severe toxic reactions and death following the ingestion of diethyltoluamide-containing insect repellents | journal = JAMA | volume = 258 | issue = 11 | pages = 1509–11 | date = September 1987 | pmid = 3625951 | doi = 10.1001/jama.258.11.1509 }}</ref><ref>{{cite book | vauthors = Baselt RC | title = Disposition of toxic drugs and chemicals in man, 10th edition | year = 2014 | publisher = Biomedical Publications | location = Seal Beach, Ca. | isbn = 978-0-9626523-9-4 | page = 650 }}</ref>

==Overdose==

Applying DEET to the skin is safe if done as directed. Adverse reactions are very rare, about 1 in 100 million people. However, repeated use of DEET in very high concentrations can lead to [[toxic encephalopathy]] with severe neurological symptoms including seizures, tremors and slurred speech. The risk is higher for children since they have a greater surface area to body weight ratio.<ref name="ewg2018">{{cite web |title=EWG's 2018 Guide to Bug Repellents |url=https://www.ewg.org/consumer-guides/ewgs-2018-guide-bug-repellents |publisher=Environmental Working Group |access-date=9 August 2023 |date=17 July 2018 |archive-url=https://web.archive.org/web/20210410185511/https://www.ewg.org/consumer-guides/ewgs-2018-guide-bug-repellents |archive-date=10 April 2021 |url-status=live}}</ref><ref>{{cite tech report |date=August 2017 |title=Toxicological profile for DEET (N,N-Diethyl-meta-toluamide) |institution=Agency for Toxic Substances and Disease Registry |pages=74-78 |url=https://wwwn.cdc.gov/TSP/ToxProfiles/ToxProfiles.aspx?id=1451&tid=201}}</ref>

==Interactions==

Limited data indicates that combining insect repellents with DEET and sunscreen decreases the sun protection factor of the sunscreen by about a third.<ref name="cdcyb2024">{{cite web |title=Mosquitoes, Ticks & Other Arthropods - CDC Yellow Book 2024 |url=https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/mosquitoes-ticks-and-other-arthropods |access-date=2023-09-26 |publisher=Centers for Disease Control and Prevention}}</ref> Unlike [[icaridin]], the combination also increases the absorption of both significantly.<ref name="jdt2016">{{cite journal |vauthors=Rodriguez J, Maibach HI |date=2016-01-02 |title=Percutaneous penetration and pharmacodynamics: Wash-in and wash-off of sunscreen and insect repellent |url=https://www.tandfonline.com/doi/full/10.3109/09546634.2015.1050350 |journal=Journal of Dermatological Treatment |volume=27 |issue=1 |pages=11–18 |doi=10.3109/09546634.2015.1050350 |pmid=26811157 |s2cid=40319483 |issn=0954-6634}}</ref> When the two need to be used together, the repellent should be applied after the sunscreen has been absorbed, about 30 or more minutes later.<ref>{{cite web |url=http://www.besthealthmag.ca/best-you/prevention/how-to-choose-the-best-bug-repellent |title=How to choose the best bug repellent |author=<!--Staff writer(s); no by-line.--> |date= January 2000|website=Best Health |publisher=Reader's Digest Association, Inc. |access-date=June 14, 2016}}</ref>

When DEET is used in combination with insecticides for [[cockroach]]es it can strengthen the toxicity of [[carbamate]], an [[acetylcholinesterase]] inhibitor. These 1996 findings indicate that DEET has [[neurological]] effects on insects in addition to known [[olfactory]] effects, and that its toxicity is strengthened in combination with other insecticides.<ref>{{cite journal | vauthors = Moss JI | title = Synergism of toxicity of N,N-diethyl-m-toluamide to German cockroaches (Orthoptera: Blattellidae) by hydrolytic enzyme inhibitors | journal = Journal of Economic Entomology | volume = 89 | issue = 5 | pages = 1151–5 | date = October 1996 | pmid = 17450648 | doi = 10.1093/jee/89.5.1151 }}</ref>

==Damage to materials==

Unlike [[icaridin]], DEET is an effective [[solvent]]<ref name="petherick">{{cite journal|last=Petherick|first=Anna|date=2008-03-13|title=How DEET jams insects' smell sensors|url=http://www.nature.com/news/2008/080313/full/news.2008.672.html|journal=Nature News|doi=10.1038/news.2008.672|access-date=2008-03-16|url-access=subscription|doi-access=free}}</ref> and may dissolve some watch crystals,<ref name=":1" /> plastics, [[rayon]], [[spandex]], other [[synthetic fiber|synthetic fabrics]], and painted or [[varnish]]ed surfaces including nail polish. It also may act as a [[plasticizer]] by remaining inside some formerly hard plastics, leaving them softened and more flexible. DEET is incompatible with rayon, [[acetate]], or [[dynel]] clothing.<ref>{{cite PubChem |cid=4284 |title=Diethyltoluamide |access-date=7 August 2023}}</ref>

==Environmental impact==

Though DEET is not expected to [[bioaccumulation|bioaccumulate]], it has been found to have a slight [[Aquatic toxicology|toxicity]] for fresh-water [[fish]] such as [[rainbow trout]]<ref>U.S. Environmental Protection Agency. 1980. Office of Pesticides and Toxic Substances. N,N-diethyl-m-toluamide (Deet) Pesticide Registration Standard. December 1980. 83 pp.</ref> and [[tilapia]],<ref>{{cite journal | vauthors = Mathai AT, Pillai KS, Deshmukh PB | year = 1989 | title = Acute toxicity of deet to a freshwater fish, Tilapia mossambica : Effect on tissue glutathione levels | journal = [[Journal of Environmental Biology]] | volume = 10 | issue = 2 | pages = 87–91 | url = http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=ENV&recid=2427671&q=DEET+fish+-permethrin&uid=791055180&setcookie=yes | url-status = dead | archive-url = https://web.archive.org/web/20071107050439/http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=ENV&recid=2427671&q=DEET+fish+-permethrin&uid=791055180&setcookie=yes | archive-date = 2007-11-07 }}</ref> and it also has been shown to be toxic for some species of freshwater [[zooplankton]].<ref name=pm15750774>{{cite journal | vauthors = Seo J, Lee YG, Kim SD, Cha CJ, Ahn JH, Hur HG | s2cid = 31723995 | title = Biodegradation of the insecticide N,N-diethyl-m-toluamide by fungi: identification and toxicity of metabolites | journal = Archives of Environmental Contamination and Toxicology | volume = 48 | issue = 3 | pages = 323–8 | date = April 2005 | pmid = 15750774 | doi = 10.1007/s00244-004-0029-9 }}</ref> DEET has been detected at low concentrations in water bodies as a result of production and use, such as in the [[Mississippi River]] and its tributaries, where a 1991 study detected levels varying from 5 to 201 [[nanogram|ng]]/L.<ref>{{cite web| first1 = Errol | last1 = Zeiger | first2 = Raymond | last2 = Tice | first3 = Brigette | last3 = Brevard | date = 1999 | title = N,N-Diethyl-m-toluamide (DEET) <nowiki>[134-62-3]</nowiki> – Review of Toxicological Literature |url=https://ntp.niehs.nih.gov/ntp/htdocs/chem_background/exsumpdf/deet_508.pdf |url-status=dead |archive-url=https://web.archive.org/web/20121009105256/http://ntp.niehs.nih.gov/ntp/htdocs/Chem_Background/ExSumPdf/DEET.pdf |archive-date=October 9, 2012 }}</ref>

A 1975 study analyzed the effects of DEET on communities of freshwater organisms native to Chinese waterways and found that DEET was moderately toxic to aquatic organisms compared to other commercial insect repellants. The most-at-risk organisms were [[algae]] colonies which often experienced "significant biomass decline and community composition shift[s]" when exposed to DEET at 500 ng/L.<ref name="pmidhttps://doi.org/10.1016/j.ecoenv.2019.109881">{{cite journal| author1=Schmoldt A |author2=Benthe HF|author3= Haberland G| title=Digitoxin metabolism by rat liver microsomes. | journal=Biochem Pharmacol | year= 1975 | volume= 24 | issue= 17 | pages= 1639–41 | pmid=10 | doi= 10.1016/0006-2952(75)90094-5| url=https://pubmed.ncbi.nlm.nih.gov/10 | hdl=10033/333424 | hdl-access=free }} </ref>

DEET is biodegraded by fungi into products less toxic to zooplankton.<ref name=pm15750774/> It degrades well under aerobic conditions, but poorly and slowly under anaerobic conditions.<ref>{{cite journal |last1=Weeks |first1=JA |last2=Guiney |first2=PD |last3=Nikiforov |first3=AI |title=Assessment of the environmental fate and ecotoxicity of N,N-diethyl-m-toluamide (DEET). |journal=Integrated Environmental Assessment and Management |date=January 2012 |volume=8 |issue=1 |pages=120–34 |doi=10.1002/ieam.1246 |pmid=22006575|s2cid=5370204 }}</ref>

==Mechanism of action==

DEET is thought to provide protection from mosquitos via two pathways, both by negatively impacting mosquito [[odorant receptors]] at a distance, and by negatively impacting mosquito [[Chemoreceptor|chemoreceptors]] upon contact.<ref name=":3" /> The exact mechanisms are still being researched, but the two most likely hypotheses are the "smell and avoid hypothesis" (that DEET has an unpleasant odor to insects), and the "bewilderment hypothesis" (that smelling DEET confuses insects).<ref name=":3" />

An alternative hypothesis is that DEET "masks" humans by reducing the volatility of skin odorants that are attractive to insects.<ref>{{cite journal | vauthors = Afify A, Betz JF, Riabinina O, Lahondère C, Potter CJ | title = Commonly Used Insect Repellents Hide Human Odors from Anopheles Mosquitoes | journal = Current Biology | volume = 29 | issue = 21 | pages = 3669–3680.e5 | date = November 2019 | pmid = 31630950 | pmc = 6832857 | doi = 10.1016/j.cub.2019.09.007 | bibcode = 2019CBio...29E3669A }}</ref>

==Synthesis==

A slightly yellow liquid at [[room temperature]], it can be prepared by converting [[M-Toluic acid|''m''-toluic acid]] (3-methylbenzoic acid) to the corresponding [[acyl chloride]] using [[thionyl chloride]] (SOCl₂), and then allowing that product to react with [[diethylamine]]:<ref>{{cite journal | title = An interesting and successful organic experiment (CEC) | page = 631 | journal = [[J. Chem. Educ.]] | last = Wang | first = Benjamin J-S. | year = 1974 | volume = 51 | issue = 10 | doi = 10.1021/ed051p631.2}}</ref><ref>{{cite book | title = Introduction to organic laboratory techniques | first = Donald L. | last = Pavia | isbn = 978-0-534-40833-6 | publisher = Cengage Learning | year = 2004 | pages = 370–376 | url = https://books.google.com/books?id=ega5c11VHvkC&pg=PA370 | format = [[Google Books]] excerpt}}</ref>

:[[File:Preparation of DEET.png|500px]]

==History==

DEET was developed in 1944<ref name=":0">{{cite patent | inventor = Gertler S | pubdate = 1946-10-01 | title = N,N-diethylbenzamide as an insect repellent | country= US | number = 2408389 }}</ref> by Samuel Gertler<ref name=":0" /> of the [[United States Department of Agriculture]] for use by the [[United States Army]],<ref>{{cite journal | vauthors = Katz TM, Miller JH, Hebert AA | title = Insect repellents: historical perspectives and new developments | journal = Journal of the American Academy of Dermatology | volume = 58 | issue = 5 | pages = 865–71 | date = May 2008 | pmid = 18272250 | doi = 10.1016/j.jaad.2007.10.005 | url = http://www.jaad.org/article/S0190-9622%2807%2901467-3/pdf | access-date = 2015-08-16 }}</ref> following its experience of [[jungle warfare]] during [[World War II]]. It was originally tested as a pesticide on farm fields, and entered military use in 1946 and civilian use in 1957. It was used in [[Vietnam]] and Southeast Asia.<ref>{{cite book | author = Committee on Gulf War and Health: Literature Review of Pesticides and Solvents | title = Gulf War and Health: Volume 2. Insecticides and Solvents | publisher = [[National Academies Press]] | year = 2003 | location = Washington, D.C. | isbn = 978-0-309-11389-2 | url = http://www.nap.edu/catalog.php?record_id=10628| doi = 10.17226/10628 }}</ref>

In its original form, known as "bug juice", the application solution was composed of 75% DEET and 25% ethanol.<ref name=":1">{{cite journal | vauthors = Kitchen LW, Lawrence KL, Coleman RE | title = The role of the United States military in the development of vector control products, including insect repellents, insecticides, and bed nets | journal = Journal of Vector Ecology | volume = 34 | issue = 1 | pages = 50–61 | date = June 2009 | pmid = 20836805 | doi = 10.1111/j.1948-7134.2009.00007.x | url = http://onlinelibrary.wiley.com/store/10.1111/j.1948-7134.2009.00007.x/asset/j.1948-7134.2009.00007.x.pdf;jsessionid=C27405CAFADCFAC9C763F9D5E949C378.f01t02?v=1&t=iviupb7a&s=536011e3c38f825d56f93eae230a1191c5119123&systemMessage=Wiley+Online+Library+will+be+unavailable+on+Saturday+26th+November+2016+from+07%3A00-11%3A00+GMT+%2F+02%3A00-06%3A00+EST+%2F+15%3A00-19%3A00+SGT+for+essential+maintenance.++Apologies+for+the+inconvenience. }}{{Dead link|date=November 2019 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Later, a new version of the repellent was developed by the U.S. Army and the USDA. This formulation consisted of DEET and a mixture of polymers that extended its release and reduced its evaporation rate.<ref>{{cite journal |last1=Kitchen |first1=Lynn W. |last2=Lawrence |first2=Kendra L. |last3=Coleman |first3=Russell E. |date=2009-07-10 |title=The role of the United States military in the development of vector control products, including insect repellents, insecticides, and bed nets |url=http://doi.wiley.com/10.1111/j.1948-7134.2009.00007.x |journal=Journal of Vector Ecology |language=en |volume=34 |issue=1 |pages=50–61 |doi=10.1111/j.1948-7134.2009.00007.x|pmid=20836805 }}</ref> This extended-release application was registered by the [[Environmental Protection Agency]] in 1991.<ref name=":1" />

== See also ==

* [[Citronella oil]]

* [[DDT]], another [[insecticide]] used for [[Vector (epidemiology)|disease vector]] [[vector control|control]]

* [[Ethyl butylacetylaminopropionate]] (IR3535)

* [[Icaridin]]

* [[Lemon eucalyptus]]

* [[p-Menthane-3,8-diol]] (PMD)

* [[Permethrin]], a [[pyrethroid]] [[insecticide]] that can be applied to clothing to help prevent bites

* [[SS220]]

* [[Anthranilate-based insect repellents]]

{{Reflist|30em}}

== Further reading ==

{{refbegin}}

* {{cite journal | vauthors = Fradin MS | s2cid = 35046348 | title = Mosquitoes and mosquito repellents: a clinician's guide | journal = Annals of Internal Medicine | volume = 128 | issue = 11 | pages = 931–40 | date = June 1998 | pmid = 9634433 | doi = 10.7326/0003-4819-128-11-199806010-00013 | citeseerx = 10.1.1.691.2193 }}

{{refend}}

{{Commons category|DEET}}

* [http://npic.orst.edu/factsheets/archive/DEETtech.pdf DEET Technical Fact Sheet – National Pesticide Information Center]

* [http://npic.orst.edu/wnv/ West Nile Virus Resource Guide – National Pesticide Information Center]

* [https://web.archive.org/web/20071031015231/http://www.health.state.ny.us/nysdoh/westnile/education/2737.htm Health Advisory: Tick and Insect Repellents, New York State]

* [https://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm US Centers for Disease Control information on DEET]

* [https://www.epa.gov/insect-repellents/deet US Environmental Protection Agency information on DEET]

* [http://www.gulflink.osd.mil/library/randrep/pesticides_paper/mr1018.8.ch5.html Review of scientific literature on DEET] {{Webarchive|url=https://web.archive.org/web/20161210003835/http://www.gulflink.osd.mil/library/randrep/pesticides_paper/mr1018.8.ch5.html |date=2016-12-10 }} (from a [[RAND Corporation]] report on [[Gulf War]] illnesses)

* [https://web.archive.org/web/20101210060228/http://www.hc-sc.gc.ca/cps-spc/pubs/pest/_decisions/rrd2002-01/index-eng.php Health Canada - Re-evaluation Decision Document: Personal insect repellents containing DEET (N,N-diethyl-m-toluamide and related compounds), 2002]

{{Portal bar|Chemistry|Insects}}

[[Category:3-Tolyl compounds]]