This page shows what was measured, who it was measured in, and what that does not settle.
What Benzoyl Peroxide does in the body
Acne, and the bumps and spots of rosacea
Benzoyl peroxide is two benzene rings joined by an oxygen-oxygen bond that is deliberately weak. On warm skin that bond snaps and releases free radicals — fragments so reactive they tear apart whatever they touch first. What they touch first, in a pore, is the membrane of the bacteria living there. Because the attack is chemical vandalism rather than a lock-and-key inhibition, there is no enzyme for a bacterium to mutate and no resistance to develop. The same indiscriminate reactivity is why it bleaches towels, why it stings, and why the molecule falls apart in the tube as well as on the face.
What happened in people
Investigators’ global assessment improved against placebo, RR 1.77 (95% CI 1.37 to 2.28), 6 trials, 4,110 participants
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The recorded finding that sits closest to something a person would notice. Written into the record, not signed off, and it carries no population or interval.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
The limit that matters most
Ranked at the top of the largest topical acne network meta-analysis only in combination with a retinoid or an antibiotic, never alone
Where it acts
The skin surface and the sebaceous follicle — benzoyl peroxide acts where it is applied and decomposes within hours
Kind of result
The kind of result is not recorded
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · W9WZN9A0GM · read 2026-08-29
Where each sentence above came from
No recorded sentence describes the change this makes in a way that stands on its own. The page opens with what it is taken for instead, and the recorded explanation follows below.
Shown as the opening line on this page.
A limit recorded against this substance. Not signed off as a reviewed claim.
The four opening statements run to 133 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
Formulation
A formulation is the exact made-up form a substance comes in.
A picture of it, and where the picture fails
It is like the difference between a whole bean and instant coffee.
Where that stops being true. Coffee tastes different. A formulation can change how much reaches the blood.
What people get wrong. Two products with the same name are assumed to behave the same. They often do not.
The specific composition and physical form of a product, including salt, excipients and release profile.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Investigators’ global assessment of improvement at 12 weeks against placebo
✓ The study showed what it set out to show
Who was studied
Cochrane overview pooled benzoyl peroxide against placebo, investigators’ assessment (CD014918)
How many people
4110
Study design
Overview of systematic reviews, pooled randomised evidence
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
RR 1.77 (95% CI 1.37 to 2.28), 6 trials, very low-certainty evidence by GRADE
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. The overview’s own conclusion is that no high-certainty evidence was found for the effects of any therapy it examined, and that no included review collected serious adverse event or quality-of-life data for the clinically important comparisons.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Topical gel, cream, wash and foam over the counter; microencapsulated 5% cream on prescription
Interval reported. 95% CI 1
Written into the record, not signed off as a reviewed claim.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
Bhatia ND et al. Efficacy and safety of microencapsulated benzoyl peroxide cream, 5%, in rosacea: results from two phase III, randomized, vehicle-controlled … · a recorded source, not a stored snapshot
Participants’ global self-assessment of improvement at 10 to 12 weeks against placebo
✗ The study did not show it
Who was studied
Cochrane overview pooled benzoyl peroxide against placebo, participants’ self-assessment (CD014918)
How many people
1073
Study design
Overview of systematic reviews, pooled randomised evidence
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
RR 1.44 (95% CI 0.94 to 2.22), 2 trials, very low-certainty evidence; interval crosses no effect
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. Only 2 of the many placebo-controlled trials in the underlying reviews reported the patient’s own assessment at all, against 6 reporting the investigator’s. Which endpoint gets collected is itself a finding.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Topical gel, cream, wash and foam over the counter; microencapsulated 5% cream on prescription
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
Bhatia ND et al. Efficacy and safety of microencapsulated benzoyl peroxide cream, 5%, in rosacea: results from two phase III, randomized, vehicle-controlled … · a recorded source, not a stored snapshot
Cutibacterium acnes and clindamycin-resistant C. acnes counts and lesion counts at 16 weeks, combination gel against matching clindamycin gel
Total C. acnes count P=0.002 and clindamycin-resistant count P=0.018 favouring combination; resistant counts rose more than 1,600% on clindamycin monotherapy. Lesion count reductions P<=0.046
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Seventy-nine enrolled at a single centre, 70 analysed. The microbiological result is the important one and rests on a small sample.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Topical gel, cream, wash and foam over the counter; microencapsulated 5% cream on prescription
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
Bhatia ND et al. Efficacy and safety of microencapsulated benzoyl peroxide cream, 5%, in rosacea: results from two phase III, randomized, vehicle-controlled … · a recorded source, not a stored snapshot
IGA clear or almost clear and inflammatory lesion count change at week 12 against vehicle
Two phase 3, randomised, double-blind, vehicle-controlled trials
Compared against
Not recorded for this study
Kind of result
A number that stands in for health
What was found
IGA success 43.5% against 16.1% (study 1) and 50.1% against 25.9% (study 2); lesion change -17.4 against -9.5 and -20.3 against -13.3, all P<0.001
Repeated elsewhere
Replicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. The comparator was vehicle in both trials. The publication states that the encapsulated product was not compared with unencapsulated benzoyl peroxide, so the contribution of the microcapsule itself is untested.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Topical gel, cream, wash and foam over the counter; microencapsulated 5% cream on prescription
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
Bhatia ND et al. Efficacy and safety of microencapsulated benzoyl peroxide cream, 5%, in rosacea: results from two phase III, randomized, vehicle-controlled … · a recorded source, not a stored snapshot
What we know
RNAWiki holds 4 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Start
Benzoyl Peroxide
What a person takes: Topical gel, cream, wash and foam over the counter; microencapsulated 5% cream on prescription.
The measurement behind this step
Applied to the skin as a suspension of crystals rather than a solution, because the compound is barely water-soluble. It is consumed as it acts: the peroxide bond breaks at skin temperature within hours and the drug is gone. Washes are formulated for short contact and leave-on products for extended contact. The prescription rosacea product entraps the same molecule in silica microcapsules to slow its release.
Getting in
A deliberately weak bond, applied to warm skin
The molecule is two benzene rings held together by a link between two oxygen atoms. That link is the weakest part, and body heat is enough to break it.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Benzoyl peroxide, C14H10O4, 242.23 g/mol, is a suspension of crystals rather than a solution — it is barely soluble in water. The O-O bond dissociation energy is low enough that homolysis proceeds at skin temperature over hours, which is why the drug is consumed as it acts and why storage temperature is a chemical variable rather than a convenience.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
Reaching the cell
It shatters into free radicals
The broken bond leaves two fragments each carrying an unpaired electron. Fragments like that are violently reactive and grab at the first molecule they meet.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Homolytic cleavage yields two benzoyloxy radicals, which either abstract hydrogen to give benzoic acid or decarboxylate to phenyl radicals. A competing recombination and decarboxylation route yields benzene, which is why the same reaction that kills bacteria also produces a class 1 carcinogen.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
What it acts on
The bacteria are oxidised, not inhibited
The radicals tear into the membranes and proteins of the bacteria in the pore. There is no lock being picked here — it is closer to bleach than to a key.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Radical attack oxidises Cutibacterium acnes membrane lipids and cytoplasmic proteins non-selectively. Because no single enzyme, transporter or ribosomal site is being inhibited, there is no locus at which a point mutation could confer resistance, and none has been described in six decades of use.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
The change it makes
No target means no resistance, and that is the point
This is why it is put alongside antibiotics. Clindamycin used alone multiplied the resistant bacteria on patients’ faces more than sixteenfold in sixteen weeks. The same gel with benzoyl peroxide added reduced them.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
In a 79-patient randomised comparison, clindamycin-resistant C. acnes counts rose more than 1,600% on clindamycin monotherapy at week 16 and fell on the clindamycin plus benzoyl peroxide combination (P=0.018), with resistant-organism reduction correlating with inflammatory lesion reduction (r2=0.31, P=0.016).
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
What that does for a person
Lesions fall on the doctor’s scale
Over ten to twelve weeks, doctors rated acne as improved about three-quarters more often on the drug than on placebo, and lesion counts fell by around sixteen more.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Pooled against placebo: investigators’ global assessment RR 1.77 (95% CI 1.37 to 2.28) across 6 trials in 4,110 participants; total lesion count MD -16.14 (95% CI -26.51 to -5.78); inflammatory MD -6.12; non-inflammatory MD -9.69. All estimates graded very low certainty.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
What that does for a person
What the endpoint does not measure
On the patient’s own rating of their own acne, the same pooled trials could not show a difference from placebo. And nothing in the whole review measured quality of life or serious harm.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Participants’ global self-assessment against placebo: RR 1.44 (95% CI 0.94 to 2.22), 2 trials, 1,073 participants, very low certainty. The overview records that for the clinically important comparisons, no included review collected data on serious adverse events or on quality of life.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 6 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Almost anyone with acne, at any severity, usually alongside something else. It is bought off a shelf and needs no prescription in the United States.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Safety and effectiveness of EPSOLAY for the treatment of inflammatory lesions of rosacea have not been established in pediatric patients.”
US prescribing information · 641981e6-460b-44dd-8146-306c47e5367c · read 2026-08-30
On older people, the label states: “Of the 733 subjects in the clinical trials of EPSOLAY, 127 (17%) subjects were 65 and over, while 37 (3%) subjects were 75 and over.”
US prescribing information · 641981e6-460b-44dd-8146-306c47e5367c · read 2026-08-30
On people who are pregnant, the label states: “Risk Summary The systemic exposure of benzoyl peroxide is unknown.”
US prescribing information · 641981e6-460b-44dd-8146-306c47e5367c · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary There are no data on the presence of benzoyl peroxide in human milk, its effects on the breastfed infant or its effects on milk production.”
US prescribing information · 641981e6-460b-44dd-8146-306c47e5367c · read 2026-08-30
Where the result stopped carrying
Participants’ own global self-assessment did not separate from placebo, RR 1.44 (95% CI 0.94 to 2.22)
Less serious adverse events were more common than on placebo, RR 1.46 (95% CI 1.01 to 2.11) across 13 trials
The Cochrane overview found no high-certainty evidence for any acne therapy it examined, benzoyl peroxide included
Silica microencapsulation did not prevent benzene formation at 50C in the 2024 stability testing, which is the property it was assumed to confer
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
A different form was studied
The studied form is not the form on the shelf.
On this record: This record is linked to 1 related forms. Evidence does not carry across all of them.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (10)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Prescription only
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Topical gel, cream, wash and foam over the counter; microencapsulated 5% cream on prescription
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
Applied to the skin as a suspension of crystals rather than a solution, because the compound is barely water-soluble. It is consumed as it acts: the peroxide bond breaks at skin temperature within hours and the drug is gone. Washes are formulated for short contact and leave-on products for extended contact. The prescription rosacea product entraps the same molecule in silica microcapsules to slow its release.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold and what that means for what is in the pack.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
Irritation, dryness, redness, peeling and stinging are common and dose-related, and less serious adverse events were about half again as frequent as on placebo in the pooled trials (RR 1.46, 95% CI 1.01 to 2.11). The over-the-counter label warns against contact with eyes, lips and mucous membranes and notes irreversible bleaching of hair and dyed fabric. Sun exposure should be limited. A 2024 analytical study detected benzene, a class 1 human carcinogen, in 111 marketed products at room temperature and demonstrated formation at elevated temperature and under ultraviolet light; that finding concerns product stability and exposure and is separate from anything known about the drug’s efficacy.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Cunliffe WJ, Holland KT, Bojar R, Levy SF. A randomized, double-blind comparison of a clindamycin phosphate/benzoyl peroxide gel formulation and a matching c… · a recorded source, not a stored snapshot
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Topical gel, cream, wash and foam over the counter; microencapsulated 5% cream on prescription
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
It is consumed as it acts: the peroxide bond breaks at skin temperature within hours and the drug is gone. Washes are formulated for short contact and leave-on products for extended contact. The prescription rosacea product entraps the same molecule in silica microcapsules to slow its release.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on which forms are sold and how they compare.
No source is stored against this line.
What is recorded as being sold
284 products list this as an active ingredient in the United States drug directory. 234 of them contain it and nothing else.
FDA National Drug Code directory · 71399-9474 · read 2026-08-29
They are sold as cream, emulsion, gel, liquid, lotion and ointment, taken topical.
FDA National Drug Code directory · 71399-9474 · read 2026-08-29
265 published labels name it as an active ingredient. 217 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 586df874-0f71-ed46-e063-6294a90a0a8e · read 2026-08-29
Those labels are classed as human otc drug and human prescription drug.
US prescribing information · 586df874-0f71-ed46-e063-6294a90a0a8e · read 2026-08-29
17 marketed supplement labels list this ingredient, classed as fat/fatty acid, mineral, non-nutrient/non-botanical and other combinations.
Those labels carry all other, nutrient and structure/function claims. A claim of that kind is written by the manufacturer and is not assessed by any regulator, so its presence says nothing about whether it is true.
Epsolay is topical at 3 DOSAGE FORMS AND STRENGTHS Cream, 5%., recorded as fda label in effect 2025-08-11 in the United States.
US prescribing information · 641981e6-460b-44dd-8146-306c47e5367c · read 2026-08-30
Recorded price in US: 0.02831–0.04701 USD per one millilitre, across 3 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Recorded price in US: 0.04559–0.23858 USD per one gram, across 14 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
Evidence on this page does not automatically apply to this one.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Benzoyl Peroxide studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That benzoyl peroxide outperforms a retinoid or a topical antibiotic — every pooled head-to-head comparison but one failed to separate them
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That an investigator’s grading of a face is a proxy for what the patient experiences, when the two diverged in the same pooled trials
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That silica microencapsulation is what makes the prescription rosacea product work, when no trial compared it with plain benzoyl peroxide
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That a molecule breaking down into a food preservative therefore breaks down into nothing else
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Benzoyl Peroxide are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
It works, and the Cochrane overview grades every number very low certainty
In plain words
Pooling six trials in more than four thousand people, doctors rated acne as improved more often on benzoyl peroxide than on placebo. The reviewers then rated their confidence in that result, and in every other result about every other acne treatment they looked at, as very low.
What was measured
Investigators’ global assessment and lesion counts at 10 to 12 weeks against placebo, pooled
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The 2024 Cochrane overview of systematic reviews covered six low-risk-of-bias reviews containing 275 trials in 40,910 people with acne. For benzoyl peroxide against placebo over 12 weeks it found improvement in investigators’ global assessment (RR 1.77, 95% CI 1.37 to 2.28; 6 trials, 4,110 participants) and reductions in total lesions (MD -16.14, 95% CI -26.51 to -5.78), inflammatory lesions (MD -6.12, 95% CI -11.02 to -1.22) and non-inflammatory lesions (MD -9.69, 95% CI -15.08 to -4.29), all rated very low-certainty. The authors’ stated conclusion is that they found no high-certainty evidence for the effects of any therapy included in the overview.
Written into the record, not signed off as a reviewed claim
The doctor saw an improvement the patient did not report
In plain words
The same review pooled the trials where patients rated their own acne. On the doctor’s scale benzoyl peroxide clearly beat placebo. On the patient’s own scale the result did not reach significance. Both measurements come from the same trials, of the same skin, at the same visits.
What was measured
Participants’ global self-assessment against placebo, RR 1.44 (95% CI 0.94 to 2.22)
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
For participants’ global self-assessment against placebo, the pooled estimate was RR 1.44 (95% CI 0.94 to 2.22) from 2 trials in 1,073 participants at 10 and 12 weeks — an interval crossing no effect, graded very low certainty, and summarised by the reviewers as benzoyl peroxide having little to no effect on that outcome. The investigators’ global assessment in the same review was RR 1.77 (95% CI 1.37 to 2.28) from 6 trials in 4,110 participants. The gap between an unblinded-to-improvement clinician grading a face and the person who owns that face rating it is the most useful single finding in the acne literature, and it is why this batch treats graded appearance as a surrogate throughout.
Written into the record, not signed off as a reviewed claim
Indistinguishable from both of its alternatives on almost every measure
In plain words
Head to head against a retinoid and against a topical antibiotic, benzoyl peroxide came out the same. Not worse, not better — the differences were too small and too uncertain to call, across every pooled outcome except one.
What was measured
That the choice between benzoyl peroxide, a retinoid and a topical antibiotic is an efficacy choice — the pooled head-to-head comparisons cannot separate them, and the real differences are resistance, irritation and price
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Against adapalene: percentage change in inflammatory lesions MD -7.7 (95% CI -16.46 to 1.06), non-inflammatory lesions MD -3.9 (95% CI -13.31 to 5.51), participant self-assessment RR 0.96 (0.86 to 1.06; 4 trials, 1,123 participants), investigators’ assessment RR 1.16 (0.98 to 1.37; 3 trials, 1,965 participants). The single exception favoured benzoyl peroxide on percentage change in total lesion count, MD 10.8 (95% CI 3.38 to 18.22) from one 205-patient trial. Against clindamycin: total lesions MD -3.50 (-7.54 to 0.54), inflammatory MD -1.20 (-2.99 to 0.59), non-inflammatory MD -2.4 (-5.3 to 0.5), participant self-assessment RR 0.95 (0.68 to 1.34), investigators’ assessment RR 1.10 (0.83 to 1.45; 2 trials, 2,277 participants). Almost every estimate is graded very low or low certainty.
Written into the record, not signed off as a reviewed claim
Adding it to an antibiotic reverses the resistance the antibiotic creates
In plain words
Sixteen weeks of clindamycin on its own multiplied the number of clindamycin-resistant bacteria on the face more than sixteenfold. The identical gel with benzoyl peroxide added reduced them instead, and the patients whose resistant bacteria fell were the patients whose spots cleared.
What was measured
Clindamycin-resistant Cutibacterium acnes colony counts at 16 weeks, combination against clindamycin alone
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Cunliffe and colleagues randomised 79 patients aged 13 to 30 with facial Cutibacterium acnes counts of at least 10^4 colony-forming units per square centimetre to clindamycin 1% with benzoyl peroxide 5% or to matching clindamycin 1% alone, twice daily for 16 weeks; 70 were analysed. Clindamycin-resistant organism counts fell from baseline in the combination group and rose by more than 1,600% in the clindamycin monotherapy group by week 16 (P=0.018 between groups); total C. acnes count also fell significantly with combination (P=0.002). Reduction in resistant organisms correlated with reduction in inflammatory lesions (r2=0.31, P=0.016) and total lesions (r2=0.28, P=0.027). Total lesion, inflammatory lesion and comedone reductions were all significantly greater on the combination (P<=0.046).
Written into the record, not signed off as a reviewed claim
In 2024 the safest drug in dermatology turned out to make benzene
In plain words
Benzoyl peroxide had a sixty-year reputation as harmless because it breaks down into benzoic acid, a food preservative. A published analysis in 2024 showed it also breaks down into benzene, a known human carcinogen, in the tube at room temperature, faster when warm, and in the air above skin under sunlight.
What was measured
That benzoyl peroxide is chemically inert enough to need no stability concern — a sixty-year assumption that a temperature and light stability study contradicted, without any change in what is known about its efficacy
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Kucera and colleagues detected benzene by headspace gas chromatography-mass spectrometry at 0.16 to 35.30 parts per million across 111 over-the-counter benzoyl peroxide drug products held at room temperature. A prescription encapsulated product stability-tested at 2C showed no apparent benzene formation and at 50C showed high levels, which the authors read as evidence that encapsulation may not stabilise the drug while cold storage may greatly reduce formation. In face-model experiments, product applied to polymethyl methacrylate photoprotection plates released detectable benzene into surrounding air by evaporation, with substantial additional formation under ultraviolet light at intensities below peak sunlight. The authors conclude that exposure risk arises from formation during use and is therefore independent of the benzene concentration a product starts with. Five of the eight authors are affiliated with Valisure, the analytical laboratory whose citizen petition raised the issue, which is disclosed in the paper.
Written into the record, not signed off as a reviewed claim
The rosacea product was never compared with ordinary benzoyl peroxide
In plain words
A version of benzoyl peroxide wrapped in glass microcapsules is approved on prescription for rosacea and clearly beats a dummy cream. It has never been tested against plain benzoyl peroxide, so what the microcapsules add is unknown.
What was measured
That silica microencapsulation is what makes the rosacea product work or makes it tolerable — the comparator in both pivotal trials was vehicle, and the manufacturer states no comparison with plain benzoyl peroxide was made
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Two 12-week randomised double-blind vehicle-controlled phase 3 trials randomised 733 subjects with moderate to severe rosacea 2:1 to microencapsulated benzoyl peroxide 5% cream or vehicle. IGA clear or almost clear at week 12 was 43.5% against 16.1% in study 1 and 50.1% against 25.9% in study 2; lesion count change was -17.4 against -9.5 and -20.3 against -13.3, all P<0.001, with separation by week 2. There were no treatment-related serious adverse events and 1.4% discontinued for adverse events. The paper states directly: "E-BPO was not compared with unencapsulated BPO." Registered as NCT03564119 and NCT03448939. Three authors were employees of the manufacturer.
Written into the record, not signed off as a reviewed claim
More adverse events than placebo, on the review’s own pooled estimate
In plain words
Across thirteen trials in more than four thousand people, side effects were about half again as common on benzoyl peroxide as on placebo. They were minor ones, and the confidence interval only just clears no difference.
What was measured
Incidence of a less serious adverse event against placebo, RR 1.46 (95% CI 1.01 to 2.11)
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The Cochrane overview reports that benzoyl peroxide may increase the risk of a less serious adverse event against placebo over 10 to 12 weeks: RR 1.46 (95% CI 1.01 to 2.11) from 13 trials in 4,287 participants, very low-certainty evidence. No review in the overview collected data on the frequency of participants experiencing at least one serious adverse event, or on quality of life, for any of the clinically important comparisons. That gap is not a finding about benzoyl peroxide — it is a finding about the whole topical acne literature.
This order is fixed in code and does not count clicks or time on the page.
What is not here
7 questions this page could not answer
These sections were prepared and left out because there was nothing to put in them. They are listed rather than hidden, so the gaps in this record are visible.
What was measured, goal by goal — found nothing in the sources checked.
How close this is to real life — found nothing in the sources checked.
Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
What it may clash with — found nothing in the sources checked.
Other ways to the same goal — found nothing in the sources checked.
What changed on this page — found nothing in the sources checked.
The record as stored
The full record, for auditing
Everything above is built from what is below. This layer keeps the technical vocabulary, record identifiers and every stored row, so a reader who wants to check the page can.
The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
A benzene ring bolted to a peroxide bond that breaks apart on skin into free radicals which oxidise Cutibacterium acnes to death without any target to mutate — improving investigator-rated acne across 6 trials and 4,110 patients (RR 1.77, 95% CI 1.37 to 2.28) while failing to reach significance on the patient’s own assessment (RR 1.44, 95% CI 0.94 to 2.22), all of it graded very low certainty, and shown in 2024 to degrade into benzene at storage and body temperature.
Recorded evidence blocks (8)
Q1
On the Benzoyl Peroxide label: indicated for what?
"EPSOLAY is indicated for the treatment of inflammatory lesions of rosacea in adults. EPSOLAY is indicated for the treatment of inflammatory lesions of rosacea in adults.": indications and usage on Benzoyl Peroxide's label. DailyMed label · 641981e6-460b-44dd-8146-306c47e5367c · 2025-08-11
Q2
18 registered trials of Benzoyl Peroxide — at which phases?
"The original PI left the institution prior to final IRB approval and the remaining study team did not have the resources to continue."; 1 of 18 registered studies
Show the evidence
TrialNCT05536882
withdrawn; "The original PI left the institution prior to final IRB approval and the remaining study team did not have the resources to continue."
recorded 2026-09-01 · last checked 2026-09-04
Q4
Human studies of Benzoyl Peroxide used Benzoyl peroxide 5% gel — over how long?
Human studies of Benzoyl Peroxide used "Benzoyl peroxide 5% gel". ClinicalTrials.gov · 2026-09-01
7 recorded entries; human; also "Benzoyl peroxide 3%", "Benzoyl peroxide 5%", "2.5% benzoyl peroxide gel"
Show the evidence
human
NCT01176955
Benzoyl peroxide 5% gel
NCT01428466
Benzoyl peroxide 3%
NCT01428466
Benzoyl peroxide 5%
NCT01472900
2.5% benzoyl peroxide gel
NCT01706250
PROACTIV (2.5% BPO) Renewing Cleanser
NCT02073461
Benzoyl Peroxide 2.5%
1 more recorded row
humanNCT02073461
Benzoyl Peroxide 5%
recorded 2026-09-01 · last checked 2026-09-04
Q5
Which 2 trials of Benzoyl Peroxide posted no result?
Posted no result
2 of 2 completed trials
Registrations
NCT01428466 and NCT01472900
Completion dates
oldest 2011-02-15; newest 2012-04
Show the evidence
Trial
NCT01428466
2011-02-15
NCT01472900
2012-04
Q6
At the median, Benzoyl Peroxide's trials enrolled 37.5 people — anything larger?
Median enrolment
37.5
Largest enrolment
1670
Registered trials counted
18
Q7
What do 333 spontaneous reports say about Benzoyl Peroxide — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Benzoyl Peroxide appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 333 reaction mentions were counted: erythema 70; swelling face 52; rash 36; hypersensitivity 32. FAERS via Open Targets · CHEMBL1200370 · 2026-06-24
Show the evidence
erythema
70
swelling face
52
rash
36
hypersensitivity
32
pruritus
32
skin burning sensation
31
4 more recorded rows
dry skin
29
skin irritation
20
application site erythema
17
skin exfoliation
14
recorded 2026-06-24 · last checked 2026-09-04
Q8
Which 10 reactions does Benzoyl Peroxide's label not list?
ChEMBL 37 — CC BY-SA 3.0 Unported · ChEMBL ATC CC BY-SA · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
✗ required summary fields resolved: 4 required field(s) not terminal: Why people use it, Best-supported result, Biggest unanswered question, Human evidence
✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 6 source rows
✓ no critical contamination: no quarantine open
✓ canonical metadata passed: slug and display name present
✓ no raw internal fields: enforced by the copy-contract test over the rendered page
This is a record of evidence. It is not medical advice, and it does not say this substance suits you. Nothing here says any substance on RNAWiki is appropriate for a child.