Benzoyl peroxide is a commonly recommended active ingredient for reducing acne. It works by eliminating Cutibacterium acnes, the bacteria responsible for inflammation, as well as reducing excess sebum and removing keratin build-up in the stratum corneum. Available over-the-counter or by prescription, depending on the concentration and severity of the acne, it nevertheless raises many questions and is often the subject of myths. Here are the answers to the most frequent misconceptions.
The myths surrounding benzoyl peroxide.
Summary
- Myth No. 1: Benzoyl peroxide causes skin ageing
- Myth No. 2: Applying thick layers of benzoyl peroxide guarantees quick results
- Myth No. 3: The effects of benzoyl peroxide are instantaneous
- Myth No. 4: Benzoyl peroxide permanently eliminates acne
- Myth No. 5: Benzoyl peroxide makes the skin dependent
- Myth No. 6: Benzoyl peroxide is ineffective against blackheads
- Myth No. 7: Benzoyl peroxide bleaches clothing
- Myth No. 8: Benzoyl peroxide is prohibited for pregnant women
- Sources
Published on February 4, 2025, by Lilia, Scientific Editor — 6 min of reading
Themes:
Myth No. 1: Benzoyl peroxide causes skin ageing.
Yes and no. For it to exert its properties, benzoyl peroxide generates free radicals, which, in excess, can potentially be harmful to the body and impair the proper functioning of cells. They are often linked to oxidative stress, due to an imbalance between the production of free radicals and antioxidants. However, in topical use and at usual concentrations, there is no solid evidence that benzoyl peroxide accelerates skin ageing. Nevertheless, exposure to the sun can lead to the production of excess free radicals. It is therefore strongly recommended to avoid sun exposure after applying this product as this could lead to an excessive generation of free radicals.
Myth No. 2: Applying thick layers of benzoyl peroxide guarantees quick results.
No. A thin layer of product or a localised application is more suitable for a product like the benzoyl peroxide, which can come in high concentrations (10%). An excessive application can increase, or even cause, a risk of irritation and skin reactions, such as erythema and burns, and will not have a faster effect on acne. Therefore, it is important to follow the recommendations given by health professionals regarding the application of benzoyl peroxide and not to use it excessively.
Myth No. 3: The effects of benzoyl peroxide are instantaneous.
No. Many believe that benzoyl peroxide provides immediate results, but it typically takes several weeks of regular use to see a noticeable improvement in the skin. According to the results of a study evaluating the effectiveness of a combination of an antibiotic (clindamycin) and benzoyl peroxide, compared to benzoyl peroxide used alone, it was observed that benzoyl peroxide begins to produce visible effects from the second week of treatment, but its optimal effectiveness is reached around the twelfth week. However, whether used as a monotherapy or in combination, the effect of the treatment is not immediate.
Efficacy of combined or monotherapy treatments of benzoyl peroxide.
Source: CHEN D. & al. An aqueous gel fixed combination of clindamycin phosphate 1.2% and benzoyl peroxide 2.5% for the once-daily treatment of moderate to severe acne vulgaris: assessment of efficacy and safety in 2813 patients. National Center for Biotechnology Information (2008).
Myth No. 4: Benzoyl peroxide permanently eliminates acne.
No, not always. Although benzoyl peroxide is effective in reducing acne by breaking down Cutibacterium acnes, the bacteria responsible for skin inflammation, and it also reduces excess sebum and exfoliates the skin, it does not necessarily eliminate acne permanently. Indeed, acne can reappear if the treatment is discontinued or if the triggering factors persist.
Myth No. 5: Benzoyl peroxide makes the skin dependent.
No. This myth suggests that once stopped, acne would return more severely. When users stop applying benzoyl peroxide, they may notice a resurgence of acne outbreaks. This does not indicate an addiction, but simply that the causes of acne are not permanently resolved. Benzoyl peroxide controls the symptoms, but, unlike some medications, it does not alter the receptors or biological functions of the skin in a way that creates a dependency.
Myth No. 6: Benzoyl peroxide is ineffective against blackheads.
No. Although primarily used to treat inflammatory spots, benzoyl peroxide also has a keratolytic action, which helps to prevent and reduce blackheads. These retentional lesions result from the accumulation of sebum, due to hyperseborrhoea, and dead cells, clogging the pores. Benzoyl peroxide works by limiting the excessive production of keratin, responsible for the thickening of the horny layer and the obstruction of follicles. According to a review published in Expert Opinion on Pharmacotherapy, experimental models show that benzoyl peroxide can reduce the size of comedones by up to 50%.
Myth No. 7: Benzoyl peroxide bleaches clothing.
Yes, indeed, benzoyl peroxide is a bleaching agent often used in the food industry to bleach flour by oxidising natural pigments, it is also used to bleach certain materials. Thus, benzoyl peroxide can discolour textiles such as coloured and dark fabrics as well as hair, particularly if it is dyed.
Myth No. 8: Benzoyl peroxide is prohibited for pregnant women.
No. The benzoyl peroxide is classified in category C in terms of risks for pregnant women, meaning it poses a risk to the foetus. It is not prohibited, but this depends on the risk-benefit balance for the patient. According to Vidal, precautions should be taken but benzoyl peroxide is not explicitly banned and is not considered teratogenic. However, as pregnant women have more sensitive skin and are therefore more prone to skin reactions, it is recommended to be cautious.
Sources
CHEN D. & al. An aqueous gel fixed combination of clindamycin phosphate 1.2% and benzoyl peroxide 2.5% for the once-daily treatment of moderate to severe acne vulgaris: evaluation of effectiveness and safety in 2813 patients. National Centre for Biotechnology Information (2008).
STEVEN R. & others. Benzoyl peroxide: a review of its current application in the treatment of acne vulgaris. Expert Opinion on Pharmacotherapy (2009).
VIDAL. Active substance benzoyl peroxide. (2013).
HELFRICH Y. R. Treatment of Acne in Pregnancy. The Journal of the American Board of Family Medicine (2016).
ZHANG Q. & al. Topical Benzoyl Peroxide for Acne. Cochrane Library (2020).
GOODMAN M.B. & et al. Benzoyl Peroxide. National Centre for Biotechnologies Information (2024).
