Editing Benzoyl peroxide

{{Short description|Chemical compound with uses in industry and acne treatment}}
{{Use dmy dates|date=March 2024}}
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{Infobox drug
| image             = Benzoyl-peroxide.svg
| image_class       = skin-invert-image
| width             = 
| alt               = 
| image2            = Benzoyl-peroxide-from-xtal-3D-bs-17.png
| image_class2      = bg-transparent
| width2            = 
| alt2              = 
| caption           = Skeletal formula (top) Ball-and-stick model (bottom)

<!-- Clinical data -->
| pronounce         =
| tradename         = Benzac, Panoxyl, others
| Drugs.com         = {{Drugs.com|ppa|benzoyl-peroxide}}
| MedlinePlus       = a601026
| DailyMedID        = Benzoyl peroxide
| pregnancy_AU      = <!-- A/B1/B2/B3/C/D/X -->
| pregnancy_AU_comment =      
| pregnancy_category= 
| routes_of_administration = [[Topical administration|Topical]]
| class             = 
| ATC_prefix        = D10
| ATC_suffix        = AE01
| ATC_supplemental  = {{ATC|D10|AE51}}

| legal_AU = S5
| legal_AU_comment = /{{nbsp}}S4/{{nbsp}}S2<ref>{{cite web | title=Therapeutic Goods (Poisons Standard—October 2024) Instrument 2024 | website=Federal Register of Legislation | date=30 September 2024 | url=https://www.legislation.gov.au/F2024L01228 | access-date=19 December 2024}}</ref>
| legal_CA = <!-- OTC, Rx-only, Schedule I, II, III, IV, V, VI, VII, VIII -->
| legal_CA_comment = 
| legal_DE = <!-- Anlage I, II, III or Unscheduled-->
| legal_DE_comment = 
| legal_NZ = <!-- Class A, B, C -->
| legal_NZ_comment = 
| legal_UK = <!-- GSL, P, POM, CD, CD Lic, CD POM, CD No Reg POM, CD (Benz) POM, CD (Anab) POM or CD Inv POM / Class A, B, C -->
| legal_UK_comment = 
| legal_US = OTC
| legal_US_comment = /&nbsp;Rx-only<ref>{{cite web | title=Epsolay- benzoyl peroxide cream | website=DailyMed | date=25 April 2022 | url=https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=507e2cd7-6bcf-4606-bc62-694d64537701 | access-date=15 May 2022 | archive-date=16 May 2022 | archive-url=https://web.archive.org/web/20220516045302/https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=507e2cd7-6bcf-4606-bc62-694d64537701 | url-status=live }}</ref><ref>{{cite web | title=Epsolay- benzoyl peroxide cream | website=DailyMed | date=5 May 2022 | url=https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=2bb9bab5-770e-4e91-8d51-b9750454daf8 | access-date=19 June 2022 | archive-date=20 June 2022 | archive-url=https://web.archive.org/web/20220620010227/https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=2bb9bab5-770e-4e91-8d51-b9750454daf8 | url-status=live }}</ref>
| legal_UN = <!-- N I, II, III, IV / P I, II, III, IV-->
| legal_UN_comment = 
| legal_status      = <!--For countries not listed above-->

<!-- Pharmacokinetic data -->
| bioavailability   = 
| protein_bound     = 
| metabolism        = 
| metabolites       =
| onset             = 
| elimination_half-life = 
| duration_of_action =
| excretion         =

<!-- Identifiers -->
| CAS_number        = 94-36-0
| CAS_supplemental  = 
| PubChem           = 7187
| IUPHAR_ligand     = 
| DrugBank          = DB09096
| ChemSpiderID      = 6919
| UNII              = W9WZN9A0GM
| KEGG              = D03093
| KEGG2             = C19346
| ChEBI             = 82405
| ChEMBL            = 1200370
| NIAID_ChemDB      =
| synonyms          = benzoperoxide, dibenzoyl peroxide (DBPO), BPO

<!-- Chemical and physical data -->
| IUPAC_name        = benzoic peroxyanhydride<ref>{{BlueBook2013|rec=65.7.5  }}</ref>
| C=14 | H=10 | O=4
| SMILES            = c1ccc(cc1)C(=O)OOC(=O)c2ccccc2
| StdInChI          = 1S/C14H10O4/c15-13(11-7-3-1-4-8-11)17-18-14(16)12-9-5-2-6-10-12/h1-10H
| StdInChIKey       = OMPJBNCRMGITSC-UHFFFAOYSA-N
| density           = 1.334
| density_notes     = 
| melting_point     = 103
| melting_high      = 105
| melting_notes     = decomposes
| boiling_point     = 
| boiling_notes     = 
| solubility        = poor
| specific_rotation = 
<!-- These below are the correct H and P phrases for benzoyl peroxide, but the drug template does not support them. The chembox does. -->
<!-- | HPhrases          = {{H-phrases|242|317|319|410}}
| PPhrases          = {{P-phrases|210|235|273|280|370+378|410}} -->
}}

'''Benzoyl peroxide''' is a [[chemical compound]] (specifically, an [[organic peroxide]]) with [[structural formula]]  {{chem2|(C6H5\sC(\dO)O\s)2}}, often abbreviated as (BzO)<sub>2</sub>.  In terms of its structure, the molecule can be described as two [[benzoyl]] ({{chem2|C6H5\sC(\dO)\s}}, Bz) groups connected by a [[peroxide]] ({{chem2|\sO\sO\s}}).  It is a white granular  solid with a faint odour of [[benzaldehyde]], poorly soluble in water but soluble in [[acetone]], [[ethanol]], and many other organic solvents. Benzoyl peroxide is an [[oxidizer]], which is principally used in the production of [[Polymer|polymers]].<ref name=Ullmann/><!-- <ref>{{cite journal |doi=10.1107/S0567740870005307|title=The crystal and molecular structures of (A) 2,2'-diiodo- (B) 2,2'-dibromo- (C) 2,2'-dichloro- (D) 2-iodo-2'-bromo- and (E) 2-iodo-2'-chlorodibenzoyl peroxides |year=1970 | vauthors = Gougoutas JZ, Clardy JC |journal=Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry |volume=26 |issue=12 |pages=1999–2008 }}</ref> -->

Benzoyl peroxide is mainly used in production of [[plastics]]<ref name=Ullmann/><ref name="St1998" /> and for bleaching [[flour]], [[hair bleaching|hair]], [[plastics]] and [[textile bleaching|textiles]].<ref name=Pl2012/><ref name=Pom2012>{{cite book| vauthors = Pommerville JC |title=Alcamo's Fundamentals of Microbiology: Body Systems|date=2012|publisher=Jones & Bartlett Publishers|isbn=978-1-4496-0595-7|page=214|url=https://books.google.com/books?id=cRaMAQAAQBAJ&pg=PA214|language=en|url-status=live|archive-url=https://web.archive.org/web/20170918185335/https://books.google.com/books?id=cRaMAQAAQBAJ&pg=PA214|archive-date=18 September 2017}}</ref>

As a [[bleach]], it has been used as a [[medication]] and a [[water disinfection|water disinfectant]].<ref name=St1998>{{cite book| vauthors = Stellman JM |title=Encyclopaedia of Occupational Health and Safety: Guides, indexes, directory|date=1998|publisher=International Labour Organization|isbn=978-92-2-109817-1|page=104|url=https://books.google.com/books?id=e4_S46UcI2AC&pg=PT404|language=en|url-status=live|archive-url=https://web.archive.org/web/20170918185335/https://books.google.com/books?id=e4_S46UcI2AC&pg=PT404|archive-date=18 September 2017}}</ref><ref name=Pom2012/>

As a medication, benzoyl peroxide is mostly used to treat [[acne]], either alone or in combination with other treatments.<ref name=WHO2008>{{cite book | title = WHO Model Formulary 2008 | year = 2009 | isbn = 978-92-4-154765-9 | vauthors = ((World Health Organization)) | veditors = Stuart MC, Kouimtzi M, Hill SR | hdl = 10665/44053 | author-link = World Health Organization | publisher = World Health Organization | pages = 307–308 }}</ref> Some versions are sold mixed with [[antibiotic]]s such as [[clindamycin]].<ref name=BNF69/><ref>{{cite book| vauthors = Braun-Falco O, Plewig G, Wolff HH, Burgdorf W  |title=Dermatology|date=2012|publisher=Springer Science & Business Media|isbn=978-3-642-97931-6|page=1039|edition=2|url=https://books.google.com/books?id=kK_rCAAAQBAJ&pg=PA1039|language=en|url-status=live|archive-url=https://web.archive.org/web/20170918185335/https://books.google.com/books?id=kK_rCAAAQBAJ&pg=PA1039|archive-date=18 September 2017}}</ref> It is on the [[WHO Model List of Essential Medicines|World Health Organization's List of Essential Medicines]].<ref name="WHO23rd">{{cite book | vauthors = ((World Health Organization)) | title = The selection and use of essential medicines 2023: web annex A: World Health Organization model list of essential medicines: 23rd list (2023) | year = 2023 | hdl = 10665/371090 | author-link = World Health Organization | publisher = World Health Organization | location = Geneva | id = WHO/MHP/HPS/EML/2023.02 | hdl-access=free }}</ref> It is available as an [[over the counter drug|over-the-counter]] and [[generic medication]].<ref name=Ric2015>{{cite book| vauthors = Hamilton R |title=Tarascon Pocket Pharmacopoeia 2015 Deluxe Lab-Coat Edition|date=2015|publisher=Jones & Bartlett Learning|isbn=978-1-284-05756-0|page=173}}</ref><ref name=BNF69>{{cite book|title=British national formulary : BNF 69|date=2015|publisher=British Medical Association|isbn=978-0-85711-156-2|page=820|edition=69}}</ref> It is also used in [[dentistry]] for [[teeth whitening]]. In 2021, it was the 284th most commonly prescribed medication in the United States, with more than 700,000 prescriptions.<ref>{{cite web | title=The Top 300 of 2021 | url=https://clincalc.com/DrugStats/Top300Drugs.aspx | website=ClinCalc | access-date=14 January 2024 | archive-date=15 January 2024 | archive-url=https://web.archive.org/web/20240115223848/https://clincalc.com/DrugStats/Top300Drugs.aspx | url-status=live }}</ref><ref>{{cite web | title = Benzoyl Peroxide - Drug Usage Statistics | website = ClinCalc | url = https://clincalc.com/DrugStats/Drugs/BenzoylPeroxide | access-date = 14 January 2024}}</ref>

==History==
Benzoyl peroxide was first prepared and described by [[Justus von Liebig]] in 1858.<ref name=lieb1858/><!--  It was the first organic peroxide prepared intentionally.{{citation needed|date=May 2022}}-->
[[Donald Holroyde Hey]] [[Fellow of the Royal Society|FRS]]<ref name="frs">{{Cite journal | vauthors = Cadogan JI, Davies DI | author-link1 = John Cadogan | doi = 10.1098/rsbm.1988.0011 | title = Donald Holroyde Hey. 12 September 1904-21 January 1987 | journal = [[Biographical Memoirs of Fellows of the Royal Society]] | volume = 34 | pages = 294–320 | year = 1988 | jstor = 770054| doi-access = free }}</ref> (12 September 1904 – 21 January 1987) was a [[Wales|Welsh]] organic chemist who inferred that the decomposition of benzoyl peroxide generated [[free radical|free phenyl radicals]].<ref>{{Cite journal | vauthors = Hey DH | author-link = Donald Holroyde Hey| title = 432. Amphoteric aromatic substitution. Part II. Reactions of benzoyl peroxide and phenylazotriphenylmethane | doi = 10.1039/JR9340001966 | journal = Journal of the Chemical Society (Resumed) | page = 1966| year = 1934 }}</ref><ref>{{cite book | veditors =  Davies J, Jenkins N, Menna B, Lynch PI | editor1-link=John Davies (historian) |title=The Welsh Academy Encyclopaedia of Wales |year=2008 |publisher=University of Wales Press |location=Cardiff |pages=367–368 |isbn=978-0-7083-1953-6}}</ref>

== Structure and reactivity ==
[[File:Dibenzoyl peroxide (CSD code =DBEZPO01).png|thumb|left|Structure of dibenzoyl peroxide from [[X-ray crystallography]].  The O=C-O-O dihedral angle is 90°.  The O-O distance is 1.434 Å.<ref>{{cite journal |doi=10.1016/0040-4020(82)80157-9|title=Radical pair in crystalline dibenzoyl peroxide evidence for triplet ground states |year=1982 | vauthors = McBride JM, Vary MW |journal=Tetrahedron |volume=38 |issue=6 |pages=765–775 }}</ref>]]
The original 1858 synthesis by Liebig reacted [[benzoyl chloride]] with [[barium peroxide]],<ref name=lieb1858>{{cite journal | vauthors = Brodie BC | title = Ueber die Bildung der Hyperoxyde organischer Säureradicale | trans-title = On the Formation of the Peroxides of Organic Acid Radicals | journal = [[Justus Liebigs Ann. Chem.]] | year = 1858 | volume = 108 | pages = 79–83 | doi = 10.1002/jlac.18581080117 | url = https://zenodo.org/record/1427113 | access-date = 2 July 2019 | archive-date = 29 November 2020 | archive-url = https://web.archive.org/web/20201129112907/https://zenodo.org/record/1427113 | url-status = live }}</ref> a reaction that probably follows this equation:
:2&nbsp;C<sub>6</sub>H<sub>5</sub>C(O)Cl + BaO<sub>2</sub> → (C<sub>6</sub>H<sub>5</sub>CO)<sub>2</sub>O<sub>2</sub> + BaCl<sub>2</sub>
Benzoyl peroxide is usually prepared by [[chemical reaction|treating]] [[hydrogen peroxide]] with [[benzoyl chloride]] under [[base (chemistry)|alkaline conditions]].
:2&nbsp;C<sub>6</sub>H<sub>5</sub>COCl + H<sub>2</sub>O<sub>2</sub> + 2&nbsp;NaOH → (C<sub>6</sub>H<sub>5</sub>CO)<sub>2</sub>O<sub>2</sub> + 2&nbsp;NaCl + 2&nbsp;H<sub>2</sub>O
The oxygen–oxygen bond in peroxides is weak. Thus, benzoyl peroxide readily undergoes [[homolysis (chemistry)|homolysis]] (symmetrical fission), forming [[radical (chemistry)|free radicals]]:
:(C<sub>6</sub>H<sub>5</sub>CO)<sub>2</sub>O<sub>2</sub> → 2&nbsp;{{chem|C|6|H|5|CO|2|•}}
The symbol <sup>•</sup> indicates that the products are radicals; i.e., they contain at least one unpaired electron. Such species are highly reactive. The homolysis is usually induced by heating. The [[half-life]] of benzoyl peroxide is one hour at 92&nbsp;°C. At 131&nbsp;°C, the half-life is one minute.<ref>{{cite thesis | vauthors = Li III H | title = Synthesis, Characterization and Properties of Vinyl Ester Matrix Resins | chapter-url = http://hdl.handle.net/10919/30521 | type = Ph.D. | publisher = University of Vermont | chapter = Chapter 2 | year = 1998 | hdl = 10919/30521 | url-status = dead | archive-url = https://web.archive.org/web/20060920122734/http://scholar.lib.vt.edu/theses/available/etd-42198-113329/unrestricted/ch2.pdf | archive-date = 20 September 2006 | access-date = 17 February 2007 }}</ref>

In 1901, it was observed that the compound made the tincture of [[Guaiacum officinale|guaiacum tincture]] turn blue, a sign of [[oxygen]] being released.<ref name=kast1901>{{cite journal | vauthors = Kastle JH, Loevenhart AS | date = 1901 | title = On the Nature of Certain Oxidizing Ferments | journal = American Chemical Journal | volume = 2 | pages = 539–566 }}</ref>  Around  1905, Loevenhart reported on the successful use of benzoyl peroxide to treat various skin conditions, including [[burn]]s, chronic [[varicose|varicose leg tumors]], and [[tinea sycosis]]. He also reported animal experiments that showed the relatively low toxicity of the compound.<ref name=loev1905>{{cite journal | vauthors = Loevenhart AS | date = 1905 | title = Benzoylsuperoxyds, ein neues therapeutisches Agens | language = German | journal = Therap Monatscheftel | volume = 12 | pages = 426–428 }}</ref><ref name=Pl2012/><ref name=merk2002>{{cite journal | vauthors = Merker PC | title = Benzoyl peroxide: a history of early research and researchers | journal = International Journal of Dermatology | volume = 41 | issue = 3 | pages = 185–8 | date = March 2002 | pmid = 12010349 | doi = 10.1046/j.1365-4362.2002.01371.x | s2cid = 24091844 }}</ref>

Treatment with benzoyl peroxide was proposed for wounds in 1929, and for [[sycosis vulgaris]] and [[acne miliaris necrotica|acne varioliformis]] in 1934.<ref name=merk2002/> However, preparations were often of questionable quality.<ref name=Pl2012>{{cite book| vauthors = Plewig G, Kligman AM |title=ACNE and ROSACEA|date=2012|publisher=Springer Science & Business Media |isbn=978-3-642-59715-2 |page=613 |edition=3 |url=https://books.google.com/books?id=0cD-CAAAQBAJ&pg=PA613|language=en|url-status=live|archive-url=https://web.archive.org/web/20170918185335/https://books.google.com/books?id=0cD-CAAAQBAJ&pg=PA613|archive-date=18 September 2017}}</ref>  It was officially approved for the treatment of acne in the US in 1960.<ref name=Pl2012/>

===Polymerization===
Benzoyl peroxide is mainly used as a [[radical initiator]] to induce [[chain-growth polymerization]] reactions,<ref name=Ullmann>{{Ullmann | vauthors = Herbert K, Götz PH, Siegmeier R, Mayr W | title = Peroxy Compounds, Organic | doi = 10.1002/14356007.a19_199}}</ref> such as for [[polyester]] and [[poly(methyl methacrylate)]] (PMMA) resins and [[dental cement]]s and [[dental restoration|restoratives]].<ref name=IARC1999/> It is the most important among the various organic [[peroxide]]s used for this purpose, a relatively safe alternative to the much more hazardous [[methyl ethyl ketone peroxide]].<ref>{{cite web |url= https://polymerdatabase.com/polymer%20chemistry/Diaroyl%20Peroxides.html |website= Polymer Properties Database |title= Initiation By Diacyl Peroxides |access-date= 19 October 2018 |archive-date= 19 October 2018 |archive-url= https://web.archive.org/web/20181019121759/https://polymerdatabase.com/polymer%20chemistry/Diaroyl%20Peroxides.html |url-status= live }}</ref><ref>{{cite web|url=http://www.degaroute.com/sites/dc/Downloadcenter/Evonik/Product/DEGAROUTE/en/Degaroute%20Brosch%C3%BCre.pdf|title=Error - Evonik Industries AG|access-date=12 April 2011|archive-date=29 August 2021|archive-url=https://web.archive.org/web/20210829105907/https://www.degaroute.com/en/degaroute-road-markings|url-status=live}}</ref>  It is also used in rubber curing and as a finishing agent for some [[cellulose acetate|acetate yarn]]s.<ref name=IARC1999/>

== Other uses ==
[[Image:Benzoyl peroxide gel.jpg|thumb|right|Tube of a water-based 5% benzoyl peroxide preparation for the treatment of [[Acne vulgaris|acne]]]]

Benzoyl peroxide is effective for treating [[Acne vulgaris|acne lesions]]. It does not induce [[antibiotic resistance]].<ref name="Simonart2012">{{cite journal | vauthors = Simonart T | s2cid = 12200694 | title = Newer approaches to the treatment of acne vulgaris | journal = American Journal of Clinical Dermatology | volume = 13 | issue = 6 | pages = 357–64 | date = December 2012 | pmid = 22920095 | doi = 10.2165/11632500-000000000-00000 }}</ref><ref name="Seidler2010"/> It may be combined with [[salicylic acid]], [[sulfur]], [[erythromycin]] or [[clindamycin]] ([[antibiotics]]), or [[adapalene]] (a synthetic [[retinoid]]).  Two common [[combination drug]]s include [[benzoyl peroxide/clindamycin]] and [[adapalene/benzoyl peroxide]], [[adapalene]] being a chemically stable retinoid that can be combined with benzoyl peroxide<ref>{{cite book | vauthors = Tolaymat L, Dearborn H, Zito PM | chapter = Adapalene |date=2022 | chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK482509/ | title = StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=29494115 |access-date=24 July 2022 }}</ref> unlike [[Tazarotene|tezarotene]] and [[tretinoin]]. Combination products such as benzoyl peroxide/clindamycin and benzoyl peroxide/[[salicylic acid]] appear to be slightly more effective than benzoyl peroxide alone for the treatment of acne lesions.<ref name="Seidler2010">{{cite journal | vauthors = Seidler EM, Kimball AB | title = Meta-analysis comparing efficacy of benzoyl peroxide, clindamycin, benzoyl peroxide with salicylic acid, and combination benzoyl peroxide/clindamycin in acne | journal = Journal of the American Academy of Dermatology | volume = 63 | issue = 1 | pages = 52–62 | date = July 2010 | pmid = 20488582 | doi = 10.1016/j.jaad.2009.07.052 }}</ref> The combination [[tretinoin/benzoyl peroxide]] was approved for medical use in the United States in 2021.

Benzoyl peroxide for acne treatment is typically applied to the affected areas in gel, cream, or liquid, in concentrations of 2.5% increasing through 5.0%, and up to 10%.<ref name="Simonart2012"/> No strong evidence supports the idea that higher concentrations of benzoyl peroxide are more effective than lower concentrations.<ref name="Simonart2012"/>

=== Mechanism of action ===
Classically, benzoyl peroxide is thought to have a three-fold activity in treating acne. It is sebostatic, comedolytic, and inhibits growth of  ''[[Cutibacterium acnes]]'', the main [[bacterium]] associated with acne.<ref name="Simonart2012"/><ref name=":0">{{cite journal | vauthors = Cotterill JA | title = Benzoyl peroxide | journal = Acta Dermato-Venereologica. Supplementum | volume = 89 | pages = 57–63 | date = 1 January 1980 | doi = 10.2340/00015555895763 | pmid = 6162349 | doi-access = free }}</ref>  In general, acne vulgaris is a hormone-mediated inflammation of sebaceous glands and hair follicles. Hormone changes cause an increase in keratin and sebum production, leading to blocked drainage. ''C. acnes'' has many lytic enzymes that break down the proteins and lipids in the sebum, leading to an inflammatory response. The free-radical reaction of benzoyl peroxide can break down the keratin, therefore unblocking the drainage of sebum (comedolytic). It can cause nonspecific peroxidation of ''C. acnes'', making it bactericidal,<ref name=Pl2012/> and it was thought to decrease sebum production, but  disagreement exists within the literature on this.<ref name=":0" /><ref name=":1">{{cite journal | vauthors = Worret WI, Fluhr JW | title = [Acne therapy with topical benzoyl peroxide, antibiotics and azelaic acid] | language = German | journal = Journal der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology | volume = 4 | issue = 4 | pages = 293–300 | date = April 2006 | pmid = 16638058 | doi = 10.1111/j.1610-0387.2006.05931.x | trans-title = Acne therapy with topical benzoyl peroxide, antibiotics and azelaic acid | s2cid = 6924764 }}</ref>

Some evidence suggests that benzoyl peroxide has an anti-inflammatory effect as well. In micromolar concentrations it prevents neutrophils from releasing reactive oxygen species, part of the inflammatory response in acne.<ref name=":1" />

=== Side effects ===
[[File:BenzoperoxideRx.JPG|right|thumb|Skin irritation due to benzoyl peroxide]]
Application of benzoyl peroxide to the skin may result in redness, burning, and irritation. This side effect is dose-dependent.<ref name=WHO2008>{{cite book | title = WHO Model Formulary 2008 | year = 2009 | isbn = 978-92-4-154765-9 | vauthors = ((World Health Organization)) | veditors = Stuart MC, Kouimtzi M, Hill SR | hdl = 10665/44053 | author-link = World Health Organization | publisher = World Health Organization | pages = 307–308 }}</ref><ref name=Ric2015>{{cite book| vauthors = Hamilton R |title=Tarascon Pocket Pharmacopoeia 2015 Deluxe Lab-Coat Edition|date=2015|publisher=Jones & Bartlett Learning|isbn=978-1-284-05756-0|page=173}}</ref>

Because of these possible side effects, it is recommended to start with a low concentration and build up as appropriate, as the skin gradually develops [[drug tolerance|tolerance]] to the medication. Skin sensitivity typically resolves after a few weeks of continuous use.<ref name=":1" /><ref name="ReferenceA">{{cite book| veditors = Alldredge BK, Koda-Kimble MA, Young LY |title=Applied Therapeutics: The Clinical Use of Drugs|date=2013|publisher=Wolters Kluwer Health/Lippincott Williams & Wilkins|location=Baltimore|isbn=978-1-60913-713-7|page=949|edition=10th}}</ref> Irritation can also be reduced by avoiding harsh facial cleansers and wearing [[sunscreen]] prior to sun exposure.<ref name="ReferenceA"/>

One in 500 people experience [[hypersensitivity]] to benzoyl peroxide and are liable to experience burning, [[itching]], crusting, and possibly [[Swelling (medical)|swelling]].<ref>{{cite journal | vauthors = Cunliffe WJ, Burke B | title = Benzoyl peroxide: lack of sensitization | journal = Acta Dermato-Venereologica | volume = 62 | issue = 5 | pages = 458–9 | date = 1982 | pmid = 6183909 | doi = 10.2340/0001555562458459 |doi-access=free }}</ref><ref>{{cite web|url=http://www.mayoclinic.org/drugs-supplements/benzoyl-peroxide-topical-route/side-effects/drg-20062425|title=Benzoyl peroxide|publisher=Mayo Clinic|date=1 January 2016|url-status=live|archive-url=https://web.archive.org/web/20160718155333/http://www.mayoclinic.org/drugs-supplements/benzoyl-peroxide-topical-route/side-effects/drg-20062425|archive-date=18 July 2016}}</ref>  About one-third of people experience [[phototoxicity]] under exposure to [[ultraviolet]] (UVB) light.<ref>{{cite journal | vauthors = Jeanmougin M, Pedreiro J, Bouchet J, Civatte J | title = [Phototoxic activity of 5% benzoyl peroxide in man. Use of a new methodology] | journal = Dermatologica | volume = 167 | issue = 1 | pages = 19–23 | date = 1 January 1983 | doi = 10.1159/000249739 | pmid = 6628794 }}</ref>

=== Dosage ===
In the US, the typical concentration for benzoyl peroxide is 2.5% to 10% for both [[Prescription drug|prescription]] and [[over-the-counter drug]] preparations that are used in treatment for acne.<ref>{{Cite web |title=Benzoyl Peroxide: Side Effects, Uses, Dosage, Interactions, Warnings |url=https://www.rxlist.com/benzoyl_peroxide/generic-drug.htm |access-date=2024-08-11 |website=RxList |language=en}}</ref>

===Other medical uses===
Benzoyl peroxide is used in dentistry as a [[tooth whitening]] product.<ref>{{Cite web |title=Some Facts On Teeth Whitening |url=https://worldofdentistry.co.in/some-facts-on-teeth-whitening.php |access-date=2024-11-06 |website=worldofdentistry.co.in}}</ref>

==Safety==

===Explosion hazard===
Benzoyl peroxide is potentially [[Explosive material|explosive]]<ref>{{cite web| vauthors = Cartwright H |title=Chemical Safety Data: Benzoyl peroxide|url=http://cartwright.chem.ox.ac.uk/hsci/chemicals/benzoyl_peroxide.html|publisher=Oxford University|access-date=13 August 2011|date=17 March 2005|url-status=live|archive-url=https://web.archive.org/web/20101012224750/http://cartwright.chem.ox.ac.uk/hsci/chemicals/benzoyl_peroxide.html|archive-date=12 October 2010}}</ref> like other [[organic peroxide]]s, and can cause fires [[Pyrophoricity|without external ignition]]. The hazard is acute for the pure material, so the compound is generally used as a solution or a paste. For example, cosmetics contain only a small percentage of benzoyl peroxide and pose no explosion risk.

===Toxicity===
Benzoyl peroxide breaks down in contact with skin, producing [[benzoic acid]] and oxygen, neither of which is very toxic.<ref>{{SIDS-ref | title = Benzoyl peroxide | id = BENZOYLPER | date = April 2004}}</ref>

The [[carcinogenic]] potential of benzoyl peroxide has been investigated. A 1981 study published in the journal ''Science'' found that although benzoyl peroxide is not a carcinogen, it does promote cell growth when applied to an [[Tumor initiation|initiated tumor]]. The study concluded, "caution should be recommended in the use of this and other free radical-generating compounds".<ref>{{cite journal | vauthors = Slaga TJ, Klein-Szanto AJ, Triplett LL, Yotti LP, Trosko KE | title = Skin tumor-promoting activity of benzoyl peroxide, a widely used free radical-generating compound | journal = Science | volume = 213 | issue = 4511 | pages = 1023–5 | date = August 1981 | pmid = 6791284 | doi = 10.1126/science.6791284 | bibcode = 1981Sci...213.1023S }}</ref>

A 1999 [[International Agency for Research on Cancer|IARC]] review of carcinogenicity studies found no convincing evidence linking benzoyl peroxide acne medication to [[skin cancer]]s in humans.  However, some animal studies found that the compound could act as a carcinogen and enhance the effect of known carcinogens.<ref name=IARC1999>International Agency for Research on Cancer (1999): "Benzoyl peroxide". in ''[https://publications.iarc.fr/89 Re-evaluation of Some Organic Chemicals, Hydrazine and Hydrogen Peroxide] {{Webarchive|url=https://web.archive.org/web/20200715120252/https://publications.iarc.fr/89 |date=15 July 2020 }}''. Monographs on the Evaluation of Carcinogenic Risks to Humans, number 71, pages 345–358.  {{isbn|92-832-1271-1}}</ref>

Benzoyl peroxide can break down into carcinogen [[benzene]] at temperatures above 50&nbsp;°C.<ref>{{cite journal | vauthors = Kucera K, Zenzola N, Hudspeth A, Dubnicka M, Hinz W, Bunick CG, Dabestani A, Light DY | title = Benzoyl Peroxide Drug Products Form Benzene | journal = Environmental Health Perspectives | volume = 132 | issue = 3 | pages = 37702 | date = March 2024 | pmid = 38483533 | doi = 10.1289/EHP13984 | pmc = 10939128 | bibcode = 2024EnvHP.132c7702K }}</ref><ref>{{Cite web |title=USP Statement on Third Party Laboratory Benzene Findings {{!}} USP |url=https://www.usp.org/news/statement-on-third-party-laboratory-benzene-findings |access-date=2024-03-16 |website=www.usp.org |language=en}}</ref>

===Skin irritation===
In a 1977, study using a human maximization test, 76% of subjects acquired a contact sensitization to benzoyl peroxide. Formulations of 5% and 10% were used.<ref>{{cite journal | vauthors = Leyden JJ, Kligman AM | title = Contact sensitization to benzoyl peroxide | journal = Contact Dermatitis | volume = 3 | issue = 5 | pages = 273–5 | date = October 1977 | pmid = 145346 | doi = 10.1111/j.1600-0536.1977.tb03674.x | s2cid = 33553359 }}</ref>

The US [[National Institute for Occupational Safety and Health]] has developed criteria for a recommended standard for occupational exposure to benzoyl peroxide.<ref>{{Cite journal |date=6 June 2014 |title=Criteria for a Recommended Standard: Occupational Exposure to Benzoyl Peroxide (77-166) |url=https://www.cdc.gov/niosh/docs/77-166/default.html |url-status=live |doi=10.26616/NIOSHPUB76128 |archive-url=https://web.archive.org/web/20160809050327/http://www.cdc.gov/niosh/docs/1970/77-166.html |archive-date=9 August 2016 |access-date=15 July 2016 |doi-access=free |website=CDC - NIOSH Publications and Products|url-access=subscription }}</ref>

===Cloth bleaching===
[[File:Benzoyl peroxide stain.jpg|thumb|right|A bleached fabric stain caused by contact with benzoyl peroxide]]
Contact with [[fabric]]s or [[hair]], such as from still-moist acne medication, can cause permanent color dampening almost immediately. Even secondary contact can cause bleaching, for example, contact with a towel that has been used to wash off benzoyl peroxide-containing hygiene products.<ref>{{cite journal | vauthors = Bojar RA, Cunliffe WJ, Holland KT | title = The short-term treatment of acne vulgaris with benzoyl peroxide: effects on the surface and follicular cutaneous microflora | journal = The British Journal of Dermatology | volume = 132 | issue = 2 | pages = 204–8 | date = February 1995 | pmid = 7888356 | doi = 10.1111/j.1365-2133.1995.tb05014.x | s2cid = 22468429 }}</ref>
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==See also==

* [[Clearasil]]

== References ==
{{Reflist}}

== External links ==
*{{ICSC|0225|02}}
*{{PGCH|0052}}
*{{SIDS | title = Benzoyl peroxide | id = BENZOYLPER}}
*[https://www.americanchemistry.com/industry-groups/organic-peroxide-producers-safety-division-oppsd Organic Peroxide Producers Safety Division (OPPSD)]

{{E number infobox 920-929}}
{{Acne Agents}}
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{{Authority control}}

{{DEFAULTSORT:Benzoyl Peroxide}}
[[Category:Acne treatments]]
[[Category:Anti-acne preparations]]
[[Category:Benzene derivatives]]
[[Category:IARC Group 3 carcinogens]]
[[Category:Organic peroxides]]
[[Category:Radical initiators]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:World Health Organization essential medicines]]