BENZOYL PEROXIDE(BENZOİL PEROKSİT)

BENZOYL PEROXIDE(BENZOİL PEROKSİT)

CAS No.: 94-36-0
EC No.: 202-327-6

Synonyms:
BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; 94-36-0; Peroxide, dibenzoyl; Dibenzoyl peroxide; Benzoperoxide; Benzoyl superoxide; Acetoxyl; Benoxyl; Lucidol; Panoxyl; Benzol peroxide; Dibenzoylperoxid; Benzoylperoxid; Asidopan; Persadox; Benzac; Eloxyl; Mytolac; Oxylite; Diphenylglyoxal peroxide; Resdan Akne; Epi-Clear; Persa-Gel; Akneroxid 5; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Dry and Clear; Duresthin 5; Luperco AST; Nayper BO; Benzoylperoxyde; Loroxide; Theraderm; Incidol; Dibenzoylperoxyde; Peroxyde de benzoyle; Lucidol B 50; Lucidol G 20; Perossido di benzoile; Benzoic acid, peroxide; Acnegel; Benzaknen; Brevoxyl; Debroxide; Desanden; Novadelox; Vanoxide; Garox; Topex; Xerac; benzoyl benzenecarboperoxoate; Luperox fl; Akneroxide L; Cadox bs; Quinolor compound; Desquam E; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Benzac W; Clear By Design; Luperco AA; Cadox B; Nayper B and bo; Aztec BPO; Benzagel 10; benzoylperoxide; Lucidol (peroxide); Benzagel; Benzashave; Cadox 40E; Norox bzp-250; Norox bzp-C-35; Desquam X; Desquam-X; Acne-Aid Cream; Benbel C; Cadat BPO; Lucidol-70; Aksil 5; Lucidol 50P; Lucidol KL 50; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Oxy-10 Cover; Superox 744; Chaloxyd BP 50FT; Abcat 40; Benox 50; Diphenylperoxyanhydride; Cadox B 40E; Cadox B 50P; Cadox B 70W; Oxy 5; Oxy-5; Cadox B-CH 50; Fostex BPO; pHisoAc BP; Xerac BP; Benoxyl (5&10) Lotion; Epi Clear Antiseptic Lotion; Stri-dex B.P.; benzoic peroxyanhydride; Peroxyderm; Benzaknew; Benzoyl; BZF-60; Dermoxyl; Luzidol; Nericur; OXY-10; Peroxydex; Preoxydex; Sanoxit; Superox; Benzoylperoxid [German]; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Benzoylperoxyde [Dutch]; Cadet; dibenzoylperoxide; Benzoyl peroxyde; Akneroxid L; Dibenzoylperoxid [German]; Dibenzoylperoxyde [Dutch]; UNII-W9WZN9A0GM; Benzoyl peroxide [USAN]; Clearasil Antibacterial Acne Lotion; CCRIS 630; Lucidol 75FP; Stri-dex B.P; Oxy-L; component of Oxy-5; Peroxyde de benzoyle [French]; component of Vanoxide; HSDB 372; Xerac BP 5; BPO; Perossido di benzoile [Italian]; OXY WASH; Xerac BP 10; NSC 671; B 75W; Clearasil BP Acne Treatment Cream; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Abcure S-40-25; EINECS 202-327-6; W9WZN9A0GM; Clearasil bp acne treatment; G 20; NSC671; CHEBI:82405; Clearasil benzoyl peroxide lotion; NSC 675; NSC-671; NSC-675; C14H10O4; MFCD00003071; NCGC00159380-02; NCGC00159380-05; Benzoylperoxid (german); WLN: RVOOVR; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Benzoyl peroxide (usan); Dibenzoylperoxid (german); DSSTox_CID_1072; DSSTox_RID_77460; DSSTox_GSID_24591; Benprox; Benzefoam; Lavoclen; Pacnex; Neobenz micro; Peroxide, Benzoyl; CAS-94-36-0; Novadelox (18% benzoyl peroxide, 78% calcium sulphate, 4% magnesium carbonate); Dibenzoyl peroxide, 75%, remainder water; Superoxide, Benzoyl; Benzoyl peroxide gel; Diphenylglyoxal Superoxide; Superoxide, Diphenylglyoxal; Thermaderm; Lucilite; Lucipal; Novadeiox; Periygel; Peroxyl; Presadox; bezoyl peroxide; Florox; Benzoyl peroide; Bepio; Silica hydrogel; Triaz; Benzoyl peroxide [USAN:USP]; benzoyl-peroxide; Luperco A; di-benzoylperoxide; dibenzoy lperoxide; dibenzoyl peroxyde; dibenzoyl-peroxide; Lucidol GS; Lucidol RM; Luperco AC; Luperco AFR; BzOOBz; Nyper B; bis benzoylperoxide; Bisbenzoyl peroxide; Cadox BTA; Nyper BMT; di-benzoyl peroxide; Perkadox 20S; Cuticura acne cream; Lucidol 70; Lucidol 78; Lucidol-78; Luperox A98; BBPO; Bepio (TN); Benzagel (Salt/Mix); BENZOYL DIOXIDE; Luperco AFR-250; Sulfoxyl (Salt/Mix); Cadet BPO 78W; Cadet BPO-70W; Cadox BPO-W40; Cadox BTW-50; Benzoyl peroxide(usan); Benzoyl Peroxide [1]; Benzoyl Peroxide [2]; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Benzoyl Peroxide [3]; Benzoyl Peroxide [4]; Benzoyl Peroxide [5]; Benzoyl Peroxide [6]; Benzoyl Peroxide [7]; Benzoyl Peroxide [8]; Benzoyl Peroxide [9]; Benzoyl peroxide, USAN; Xerac BP (Salt/Mix); AcetOxyl 2.5 and 5; Benzoyl peroxide (USP); Diphenylperoxyanhydride #; SCHEMBL63; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; TRIAZ;Dibenzoyl peroxide; Fostex BPO (Salt/Mix); Aztec benzoyl peroxide-dry; ACMC-209u3h; EC 202-327-6; Benzoyl peroxide (JAN/USP); KSC486M9N; MLS000028899; BIDD:GT0840; BENZOYL PEROXIDE (WET); Aztec benzoyl peroxide-70-77; NSC675; ZINC1016; CHEMBL1200370; DTXSID6024591; CTK3I6696; KS-00000VQD; Benzoyl peroxide, remainder water; Fostex BPO Bar, Gel, and Wash; component of Vanoxide (Salt/Mix); HMS2092F22; Pharmakon1600-01503004; phenylcarbonyl benzenecarboperoxoate; NA 2085 (DOT); UN 2085 (DOT); EBD40747; Tox21_111619; ANW-43275; Benzoyl peroxide (Luperox(R) A75); Benzoyl peroxide (Luperox(R) A98); Dibenzoyl peroxide; BPO; Perkadox L; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; NSC758205; Benzoyl peroxide (Luperox(R) A70S); AKOS000120600; benzenecarboperoxoic acid benzoyl ester; Tox21_111619_1; Benzoyl peroxide (Luperox(R) A75FP); CCG-213090; DB09096; LS-1962; MCULE-5748985501; NSC-758205; SC10147; UN 2086; UN 2088; NCGC00159380-03; NCGC00159380-04; BP-21236; E928; SC-26204; SMR000058568; W 75; SBI-0206719.P001; DB-022598; B3152; Benzoyl peroxide, blend in dibutyl phthalate; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; NS00006130; Benzoyl peroxide, blend in tricresyl phosphate; C19346; D03093; AB01562988_01; Benzoyl peroxide, for synthesis, 72.0-80.0%; Mixture of dibenzoyl peroxide and calcium sulfate; A844933; Mixture of dibenzoyl peroxide and calcium sulphate; Q411424; BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; SR-05000001817; SR-05000001817-1; BRD-K59986511-001-02-3; Benzoyl peroxide, SAJ first grade, >=98.0% dry basis; F0001-2260; Luperox(R) A70S, Benzoyl peroxide, 70%, remainder water; Luperox(R) A75, Benzoyl peroxide, 75%, remainder water; Luperox(R) A98, Benzoyl peroxide, reagent grade, >=98%; BENZOYL PEROXIDE (SEE ALSO DMBA/TPA/BPO/MNNG (CAS NO. INIT/PROM)); BENZOYL PEROXIDE; BENZOİL PEROKSİT; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Benzoyl peroxide blend with dicyclohexyl phthalate, technical, ~50% (T); Luperox(R) ATC50, Benzoyl peroxide, ~50 wt. % in tricresyl phosphate; Luperox(R) AFR40, Benzoyl peroxide solution, 40 wt. % in dibutyl phthalate; BENZOYL PEROXIDE; BENZOİL PEROKSİT; Benzoyl peroxide blend with dicyclohexyl phthalate, suitable for use as a catalyst for electron microscopy. Modified to render it safe in transit.; Luperox(R) A75FP, Benzoyl peroxide, 75% remainder water, contains 25 wt. % water as stabilizer, 75%; BENZOYL PEROXIDE; BENZOİL PEROKSİT

BENZOYL PEROXIDE

How to Treat Acne with Benzoyl Peroxide
Benefits
Types of products
Side effects and precautions
Vs. salicylic acid
Other OTC treatments
Seeking medical help
Summary
What is benzoyl peroxide?
Benzoyl peroxide is a well-known ingredient for fighting acne. Available in over-the-counter (OTC) gels, cleansers, and spot treatments, this ingredient comes in different concentrations for mild to moderate breakouts.

While benzoyl peroxide can effectively get rid of bacteria and dead skin cells that clog your pores, it has limitations. Let’s cover the pros and cons and when to talk to a dermatologist (skin care specialist) if OTC products aren’t doing the job.
Is benzoyl peroxide good for acne?
Benzoyl peroxide works to treat and prevent acne by killing bacteria underneath the skin, as well as helping the pores shed dead skin cells and excess sebum (oil).
Benzoyl peroxide for pimples
Benzoyl peroxide works particularly well for inflammatory acne, which is characterized by red bumps that contain pus — pustules, papules, cysts, and nodules — instead of whiteheads and blackheads.
Benzoyl peroxide for cystic acne
Cystic acne is considered the most serious form of acne, which also makes it the most difficult to treat.
It’s characterized by hard bumps below the surface of your skin. While these pimples may have pus deep inside them, it’s difficult to identify any prominent “heads.”
P. acnes bacteria is one contributor to cystic acne, which benzoyl peroxide may help treat in combination with prescription medications.
If you have this type of acne, consult a dermatologist for your best treatment options.

Benzoyl peroxide for blackheads and whiteheads
Blackheads and whiteheads are still considered acne. However, they are classified as noninflammatory because they don’t cause the red bumps that are associated with other types of acne pimples.
You may be dealing with both of these types of acne and might be wondering if you can use benzoyl peroxide for noninflammatory spots too.
While benzoyl peroxide can help treat oil and dead skill cells that clog your pores, this may not be the best treatment option available for blackheads and whiteheads.
While benzoyl peroxide does help treat certain types of acne, topical retinoids are considered the first line of treatment. This includes adapalene and tretinoin.
Some adapalene products, such as Differin Gel, are available OTC. Tretinoin products require a prescription.
Benzoyl peroxide for acne scars
Acne scars are sometimes a result of an acne outbreak. This is especially the case with inflammatory acne, even if you successfully resist the urge to pick at the lesions.
Acne scars can worsen with sun exposure, so it’s important to wear sunscreen every day. In theory, benzoyl peroxide could also help shed dead skin cells and make the scars less prominent. However, research doesn’t support this use.
How to use benzoyl peroxide
Benzoyl peroxide comes in the form of many acne treatment products. It’s important to select the right one for your skin care concern as well as preference.

For example, you may prefer to use a wash formulated specifically for your body rather than your face. Or you might decide to choose a gel.
Another key is to choose the appropriate concentration. The concentration that you choose to use may depend on your skin.
Some people can tolerate products with a high percentage of benzoyl peroxide (up to 10 percent) on their skin. Others may prefer a lower percentage.
What concentration to use also depends on where you apply the benzoyl peroxide.
The face is rather sensitive, so many choose to use a lower concentration (around 4 percent) in that area, while the chest and back are more resilient and can tolerate a higher concentration.
Benzoyl peroxide may be found in the following acne treatment products:
acne creams and lotions: typically applied once or twice a day on the entire area of skin as both a treatment and preventive measure
face washes and foams: used once or twice a day to help prevent acne and treat existing lesions
acne body washes and soaps: ideal if you have frequent breakouts on the chest, back, and other areas of the body
gels: tend to come in the form of spot treatments with higher concentrations and are typically applied only to the affected area
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Side effects of using benzoyl peroxide on the skin
While considered safe for most people, benzoyl peroxide can cause side effects. This is especially the case when you first start using the product.
It may be helpful to use it once a day, and then build up the frequency in application over time if your skin can tolerate it. You can also minimize side effects by starting with a lower concentration.
Talk to a dermatologist about the following side effects and precautions of using benzoyl peroxide for acne.
Skin side effects
Benzoyl peroxide works by peeling away the skin to get rid of dead skin cells, excessive oil, and bacteria that may be trapped underneath.
Such effects can lead to dryness, as well as redness and excessive peeling. You might notice itching and general irritation at the site of application too.
Don’t use benzoyl peroxide if you have a sunburn.
Stained clothing and hair
Benzoyl peroxide is known for staining clothing and hair. Make sure you wash your hands thoroughly after each use.

You might also consider skipping an application right before a workout so you don’t transfer the product to your hair and clothing via sweat.
Allergic reactions
While allergic reactions from benzoyl peroxide are considered rare, they are still possible. Stop using the product immediately if the treated areas have redness and irritation.
You should go to an emergency room right away if you have severe swelling and breathing difficulties, as these may be signs of an allergic reaction.
Benzoyl peroxide and skin conditions
A dermatologist may not recommend benzoyl peroxide if you have sensitive skin, as this skin type is more prone to side effects such as rashes and irritation.
Benzoyl peroxide also might not be the best choice if you have eczema or seborrheic dermatitis.
Benzoyl peroxide vs. salicylic acid for acne
While benzoyl peroxide is a staple for treating inflammatory acne, it’s worth considering salicylic acid if you also have noninflammatory acne (blackheads and whiteheads).

Both help clean pores, but salicylic acid’s primary role is to get rid of dead skin cells. Such exfoliating effects may help treat noninflammatory lesions.
It also won’t stain your hair or clothing like benzoyl peroxide can. But it can still lead to dry, red, and peeling skin, especially when you first start using a product containing salicylic acid.
As a rule of thumb, if you have inflammatory acne along with oily, less sensitive skin, benzoyl peroxide may be the better choice.
Other OTC acne treatments
Benzoyl peroxide isn’t your only treatment option for acne and acne scars. Other OTC products can help treat bacteria, excessive oil, and dead skin cells too. Consider the following treatments:

salicylic acid
sulfur
tea tree oil
adapalene
When to see a doctor
No acne product will clear up your blemishes and scars overnight. Such is the case with benzoyl peroxide. It can take up to six weeks for new products to take full effect.
If you don’t see any improvements after six weeks, consider seeing a dermatologist. They might recommend a prescription-strength formula, especially if your acne is severe. They may also recommend an entirely different treatment option.
Be prepared to answer questions about your acne and its severity so your dermatologist can determine the best treatment option possible. They will also conduct a skin exam to see the type of acne you have.
The takeaway
Benzoyl peroxide is one of the many options available for treating acne.
Its enduring popularity goes beyond its availability and affordability — benzoyl peroxide can help treat inflammatory acne lesions and related scarring. It’s most helpful when used together with other treatments, such as topical retinoids.
Still, everyone’s skin is different, and benzoyl peroxide may not work for all. Give any new acne product several weeks to take full effect before moving on to the next one. See a dermatologist if OTC products aren’t working or if you develop a negative reaction to benzoyl peroxide.
Benzoyl peroxide
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Benzoyl peroxide
Benzoyl-peroxide.svg
Benzoyl-peroxide-3D-balls.png
Skeletal formula (top) Ball-and-stick model (bottom)
Clinical data
Trade names    Benzac, Clearasil, PanOxyl, others
Other names    benzoperoxide, dibenzoyl peroxide (DBPO)
E number    E928 (glazing agents, ...) Edit this at Wikidata
CompTox Dashboard (EPA)    
DTXSID6024591 Edit this at Wikidata
ECHA InfoCard    100.002.116 Edit this at Wikidata
Chemical and physical data
Formula    C14H10O4
Molar mass    242.230 g·mol−1
3D model (JSmol)    
Interactive image
Density    1.334 g/cm3
Melting point    103 to 105 °C (217 to 221 °F) decomposes
Solubility in water    poor mg/mL (20 °C)
SMILES[show]
InChI[show]
Data page
Benzoyl peroxide (data page)
Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula (C
6H
5−C(=O)O−)
2, often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (65H
5−C(=O)−, Bz) groups connected by a peroxide (−O−O−). 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 as in the production of polymers. [2]

As a bleach, it has been used as a medication and a water disinfectant.[3][4] In specialized contexts, the name may be abbreviated as BPO.
As a medication, benzoyl peroxide is mostly used to treat acne, either alone or in combination with other treatments.[5] Some versions are sold mixed with antibiotics such as clindamycin.[6][7] It is on the WHO List of Essential Medicines,[8] and, in the US, it is available as an over-the-counter and generic medication.[9][6] It is also used in dentistry for teeth whitening.
Benzoyl peroxide is also used for bleaching flour, hair, and textiles[10][4] It is also used in the plastics industry.[3]
Contents
1    History
2    Medical uses
2.1    Acne treatment
2.1.1    Mechanism of action
2.1.2    Side effects
2.1.3    Dosage
2.2    Other medical uses
3    Non-medical uses
3.1    Bleaching
3.2    Polymerization
4    Safety
4.1    Explosion hazard
4.2    Toxicity
4.3    Skin irritation
4.4    Cloth staining
5    Reactivity
6    References
7    External links
History
Benzoyl peroxide was first prepared and described by Liebig in 1858.[11] It was the first organic peroxide prepared intentionally.
In 1901, J. H. Kastle and his graduate student A. S. Loevenhart observed that the compound made the tincture of guaiacum tincture turn blue, a sign of oxygen being released.[12] Around 1905, Loevenhart reported on the successful use of BPO to treat various skin conditions, including burns, chronic varicose leg tumors, and tinea sycosis. He also reported animal experiments that showed the relatively low toxicity of the compound.[13][10][14]
Treatment with benzoyl peroxide was proposed for wounds by Lyon and Reynolds in 1929, and for sycosis vulgaris and acne varioliformis by Peck and Chagrin in 1934.[14] However, preparations were often of questionable quality.[10] It was officially approved for the treatment of acne in the US in 1960.[10]

Medical uses
Acne treatment
Tube of a water-based 5% benzoyl peroxide preparation for the treatment of acne
Benzoyl peroxide is effective for treating acne lesions. It does not induce antibiotic resistance.[15][16] It may be combined with salicylic acid, sulfur, erythromycin or clindamycin (antibiotics), or adapalene (a synthetic retinoid). Two common combination drugs include benzoyl peroxide/clindamycin and adapalene/benzoyl peroxide, an unusual formulation considering most retinoids are deactivated by peroxides[citation needed]. 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.[16]

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%.[15] No strong evidence supports the idea that higher concentrations of benzoyl peroxide are more effective than lower concentrations.[15]
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.[17][15] 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,[10] and it was thought to decrease sebum production, but disagreement exists within the literature on this.[18][17]

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.[18]
Side effects
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.[5][9]

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 tolerance to the medication. Skin sensitivity typically resolves after a few weeks of continuous use.[18][19] Irritation can also be reduced by avoiding harsh facial cleansers and wearing sunscreen prior to sun exposure.[19]
One in 500 people experience hypersensitivity to BPO and are liable to suffer burning, itching, crusting, and possibly swelling.[20][21] About one-third of people experience phototoxicity under exposure to ultraviolet (UVB) light.[22]
Dosage
In the U.S., the typical concentration for benzoyl peroxide is 2.5% to 10% for both prescription and over-the-counter drug preparations that are used in treatment for acne.
Other medical uses
Benzoyl peroxide is used in dentistry as a tooth whitening product.
Non-medical uses
Benzoyl peroxide is one of the most important organic peroxides in terms of applications and the scale of its production. It is often used as a convenient oxidant in organic chemistry.[citation needed]
Bleaching
Like most peroxides, is a powerful bleaching agent. It has been used for the bleaching of flour, fats, oils, waxes, and cheeses, as well as a stain remover.[23]

Polymerization
Benzoyl peroxide is also used as a radical initiator to induce chain-growth polymerization reactions,[2] such as for polyester and poly(methyl methacrylate) (PMMA) resins and dental cements and restoratives.[24] It is the most important among the various organic peroxides used for this purpose, a relatively safe alternative to the much more hazardous methyl ethyl ketone peroxide.[25][26] It is also used in rubber curing and as a finishing agent for some acetate yarns.[24]

Safety
Explosion hazard
Concentrated benzoyl peroxide is potentially explosive[27] like other organic peroxides, and can cause fires 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.[28]
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 initiated tumor. The study concluded, "caution should be recommended in the use of this and other free radical-generating compounds".[29]
A 1999 IARC review of carcinogenicity studies found no convincing evidence linking BPO acne medication to skin cancers in humans. However, some animal studied found that the compound could act as a carcinogen and enhance the effect of known carcinogens.[24]
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.[30]

The U.S. National Institute for Occupational Safety and Health has developed criteria for a recommended standard for occupational exposure to benzoyl peroxide.[31]
Cloth staining
A bleached fabric stain caused by contact with benzoyl peroxide.
Contact with fabrics 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.[32]

Reactivity
The original 1858 synthesis by Liebig reacted benzoyl chloride with barium peroxide,[11] a reaction that probably follows this equation:

The symbol • 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 °C. At 131 °C, the half-life is one minute.[33]
Benzoyl peroxide
On this page
About benzoyl peroxide
Key facts
Who can and cannot use benzoyl peroxide
How and when to use it
Side effects
How to cope with side effects
Pregnancy and breastfeeding
Cautions with other medicines
Common questions
1. About benzoyl peroxide
Benzoyl peroxide is used to treat acne. It works as an antiseptic to reduce the number of germs (bacteria) on the surface of your skin.
It comes as a gel or face wash containing 5% benzoyl peroxide. This is available to buy from pharmacies under the brand name Acnecide.
Benzoyl peroxide is sometimes mixed with potassium hydroxyquinoline sulfate. This is an "antimicrobial" ingredient that kills micro-organisms on your skin. It's sold in pharmacies as Quinoderm cream.
Some benzoyl peroxide products are available on prescription only. This is because they contain other active ingredients such as antibiotics or retinoids (exfoliants).
Many popular skincare brands also make products that contain benzoyl peroxide, but at a lower strength. These are available to buy in pharmacies, supermarkets and shops. Brands include Clean & Clear, Neutrogena and Clearasil.

2. Key facts
Benzoyl peroxide 5% takes around 4 weeks to start working.
You'll usually use it 1 or 2 times a day.
The most common side effect is skin irritation. It is better to use it less often at first, then build up as your skin gets used to it.
Pharmacy brands include Acnecide 5% gel and Acnecide Wash 5%.
Benzoyl peroxide is also an ingredient in Duac Once Daily (with clindamycin, an antibiotic) and Epiduo gel (with adapalene, a retinoid).
3. Who can and cannot use benzoyl peroxide
Most adults and children over 12 years old can use benzoyl peroxide.
Benzoyl peroxide is not suitable for some people.
To make sure benzoyl peroxide is safe for you, tell your doctor before using this medicine if you:

are allergic to benzoyl peroxide or other medicines.
have damaged or broken skin where you need to use the treatment.
have very bad acne with nodules (large, hard lumps that build up beneath the surface of the skin and can be painful) or cysts (large, pus-filled lumps that look similar to boils). These need to be treated by a doctor to avoid scarring.
4. How and when to use it
Benzoyl peroxide is for use on your skin only.
Always wash your hands before and after using this medicine.
If your skin becomes dry or starts peeling, try using benzoyl peroxide less often. Put it on once a day or once every 2 days, until your skin gets used to it.
Benzoyl peroxide can bleach or discolour your hair, as well as clothes, towels and bedding. Keep it away from hair and coloured fabrics.
How to use benzoyl peroxide 5% gel
Wash the affected area with a mild skin cleanser and water.
Gently pat your skin dry.
Put a thin layer of gel on all the affected areas. If your whole face has acne, use a strip of gel (2.5cm long) each time.
You'll usually use the gel once or twice a day. If you have sensitive skin, use the gel once a day, before going to bed.
Try to avoid strong sunlight while using benzoyl peroxide gel. Use an oil-free sunscreen, or a moisturiser or foundation with added SPF30. In stronger sunlight, use SPF30 or above. Ask a pharmacist to help you pick a sunscreen that's right for your skin type.
How to use benzoyl peroxide 5% wash
Wet the area you want to treat.
Place a small amount of the product onto your hands.
Smooth it onto the affected area.
Keep the wash on your skin for no more than 1 to 2 minutes.
Rinse your face thoroughly with water.
Gently pat your skin dry.
You'll usually use the wash 1 or 2 times a day.

How long will I use it for?
It depends on how quickly your condition improves.

Benzoyl peroxide will usually start to work within 4 weeks, but once your acne is under control you may want to keep using it to stop your acne coming back.
What if I forget to use it?
It does not matter if you forget to use benzoyl peroxide.
When you remember, start using it again once or twice a day in the same way as before.
What if I use too much?
If you use too much benzoyl peroxide, your skin may become irritated. Wash off as much as you can and wait for the irritation to go away.
When your skin has calmed down again, you can start using benzoyl peroxide again. Be careful to follow the instructions on the package.
Important
Keep benzoyl peroxide away from your eyes. If you get the gel or wash in your eyes, rinse thoroughly with lukewarm water for a few minutes or until it stops stinging.
5. Side effects
Like all medicines, benzoyl peroxide can cause side effects, although not everyone gets them.
Common side effects
These common side effects happen in more than 1 in 10 people. Talk to a doctor or pharmacist if these side effects bother you or do not go away:
dry skin
red or peeling skin
burning or stinging (skin irritation)
Serious side effects
These serious side effects are rare and happen in less than 1 in 1,000 people. Stop using benzoyl peroxide if:

the skin that you're treating becomes swollen
you get blisters on your skin
If your symptoms do not get better within a couple of days or if they get worse at any time, contact a doctor straight away.
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to benzoyl peroxide.
These are not all the side effects of benzoyl peroxide. For a full list, see the leaflet inside your medicine packet.
Information:
You can report any suspected side effects to the UK Safety Scheme
6. How to cope with side effects
What to do about:
dry skin – apply a moisturiser and lip balm regularly (the best type of moisturiser is an oil-free face moisturiser for sensitive skin). Try to take shorter showers, using warm water rather than hot.
red or peeling skin – try using the gel or wash less often, or stop using it for a few days until the irritation goes away, then start again. Do not use other products on your skin in the meantime. Speak to a doctor if your symptoms do not get better or are severe.
burning or stinging (skin irritation) – try using the gel or wash less often (once a day instead of twice, or every other day). It might help to stop using the gel for a few days until the irritation goes away, then start again. If the irritation does not go away after this time, stop using it and speak to a doctor.
7. Pregnancy and breastfeeding
It's usually safe to use benzoyl peroxide during pregnancy and while breastfeeding.
Benzoyl peroxide and breastfeeding
Although it's generally OK to use benzoyl peroxide when you're breastfeeding, do not use it on your chest area and wash your hands before touching your baby. This is so your baby does not come into contact with it.
Important
Tell a pharmacist or doctor if you're trying to get pregnant, already pregnant or breastfeeding

8. Cautions with other medicines
Some products and medicines can irritate your skin if you use them while you're treating your skin with benzoyl peroxide gel or wash.
Do not use benzoyl peroxide with any other medicines that may have drying or irritating effects on your skin. These include alcohol-based skincare products. Always check the ingredients on the label and choose products for sensitive skin.
Do not use other benzoyl peroxide products or other acne medicines (such as isotretinoin), unless your doctor or pharmacist says it's OK. It may cause your skin to become very sore.
Mixing benzoyl peroxide with herbal remedies and supplements
There's very little information about taking herbal remedies and supplements while using benzoyl peroxide.