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Benzoyl Peroxide & the Skin Microbiome

Benzoyl Peroxide & the Microbiome


Benzoyl peroxide (BPO) is well known to be used for people that have acne. Although the effect of this drug in reducing acne is clear, the effect on the skin microbiome is less known which may have a role to play in the long-term effects and symptoms of BPO usage. In this post, we will discuss what is known, and how the skin microbiome might be affected.

What is Benzoyl Peroxide and How Is It Used?

Benzoyl Peroxide (BPO) is a drug that is commonly used in the treatment of mild to moderate acne. It is often formulated with active ingredients, antibiotics, or retinoids and infused into topical skincare products such as gels, face washes, and spot treatments. Since BPO can be quite strong, each formulation will typically contain a maximum of 5% of the drug.

BPO products are generally recommended in controlled amounts, therefore are most often sold as spot creams to be used only in targeted areas. Individuals are advised to gradually increase the number of applications up to a maximum of twice in one day.

Common Side Effects of Benzoyl Peroxide

The reason that BPO should be applied with caution and control is due to common side effects that include dry skin, peeling skin, and skin irritation. These are reported to occur in just over 10% of individuals, which can be alarming, especially for those who have sensitive skin.

Excessive use of BPO has been reported to cause the skin to become very dry and flaky. In addition, the prolonged use of BPO products can also cause the skin to become over-dependant, which consequently risks the return or worsening of the acne when the treatment is stopped. What does this all mean in the context of the skin microbiome?

Skin Microbiome and Benzoyl Peroxide

The skin microbiome is made up of an organic ecosystem of trillions of bacteria that sit on the surface of the skin and acts as a first-line defence against external factors. For the skin microbiome to be at its healthiest, it needs to be balanced with a high diversity of bacteria populating the skin. Now when looking at it through the context of BPO, we are left with quite an interesting situation.

BPO claims to fight acne and potentially prevent new breakouts by working as an antiseptic to attack and reduce the bacteria on the surface of the skin. It also removes dead skin in order to unclog and minimize the appearance of pores.

As far as attacking and reducing bacteria is concerned, scientists are left with a crucial question to answer. How does BPO affect the skin microbiome and the diversity of bacteria on the skin?

Current Studies Linked to Benzoyl Peroxide

Research on this subject is mixed, with some academic papers reporting that BPO may have a link to reduced microbial diversity (as well as acne), however, other research fails to show any statistical change.

A recent study published (Zhou et al, 2022) compared skin microbiome changes in people who suffer from acne before and after the use of BPO, but found that among the top 20 bacteria species two of them (Staphylococcus, Acinetobacter) increase in abundance whilst one decreased Corynebacterium.

Another research study (Ahluwalia et al., 2019) found that although there weren’t statistically significant changes in the diversity of the skin microbiome, the use of BPO resulted in a statistically significant increase in Streptococcus mitis (S.mitis) population.

Taking a different look at things, it was found that after the use of BPO S.epidermidis increased, which could potentially inhibit the growth of harmful bacteria such as Cutibacterium acnes (C.acnes), certain strains of which are a known culprit in individuals with acne (Wang et al., 2014). However, the argument arose that even if Staphylococcus epidermidis (S. epidermidis) rose to help stave off C.acnes, could the benefits outweigh the ill effects of using BPO in general?

Next Steps for Research

To be able to answer questions like this in more depth, there is a strong need to conduct further research in a controlled environment, with the aim of decoding the impacts of BPO on the skin microbiome and the diversity of not just the most common bacteria, but also the obscure ones that one might not think to be significant.

Other questions might be, does the skin microbiome significantly change if the use of BPO becomes chronic? And does this have lasting effects and long-term ill effects on the skin?

Sequential is a testing company with years of expertise in the field of skin microbiome and genetics. We utilise deep molecular analysis and next-generation sequencing (NGS) technology to understand the impact on an individual’s microbiome from products they use, and the effect from their environment.

All of our testing is carried out in-vivo and with the utmost care for unearthing the secrets that lie on the surface of the skin. If you are interested in carrying out any research with us and testing products, you can reach us at



Skin Microbiome: refers to the collection of genomes from all the microorganisms in the environment (on your skin).

Skin Microbiota: refers to microorganisms that are found within a specific environment. Microbiota can refer to all the microorganisms found in an environment, including bacteria, viruses, and fungi.

Bacteria: bacteria are single-cell organisms that live everywhere on earth, including on the surface of the skin.

Benzoyl Peroxide: Benzoyl Peroxide (BPO) is a drug that is commonly used in the treatment of mild to moderate acne.

Streptococcus mitis (S.mitis): S.mitis is a gram-positive bacteria found mainly in the mouth but low in the skin and is usually opportunistic/pathogenic in Adults. In fact, several anti-bacterial lipids have been tested against this bacteria. On the other hand, the pre-adolescent microbiome might have more S.mitis and very little C.acne because sebaceous glands have not developed fully yet. Only after puberty do we start to see C.acne increasing and other bacteria such as S.mitis decreasing.

Cutibacterium acnes (C.acnes): is a highly prevalent bacterium that inhabits pores where sebum/natural oils are formed. it is linked to skin conditions such as acne, but only with some strains.

Staphylococcus epidermidis (S.epidermidis): is one of more than forty species of bacteria that belongs to the Staphylococcus family and is part of the organisms that normally inhabit humans, specifically the skin.

Reference List

Ahluwalia, J., Borok, J., Haddock, E. S., Ahluwalia, R. S., Schwartz, E. W., Hosseini, D., Amini, S., & Eichenfield, L. F. (2019, Mar). The microbiome in preadolescent acne: Assessment and prospective analysis of the influence of benzoyl peroxide. Pediatr Dermatol, 36(2), 200-206.

Coughlin, C. C., Swink, S. M., Horwinski, J., Sfyroera, G., Bugayev, J., Grice, E. A., & Yan, A. C. (2017, Nov). The preadolescent acne microbiome: A prospective, randomized, pilot study investigating characterization and effects of acne therapy. Pediatr Dermatol, 34(6), 661-664.

Karoglan et al, 2019

Oh, J., Conlan, S., Polley, E. C., Segre, J. A., & Kong, H. H. (2012). Shifts in human skin and nares microbiota of healthy children and adults. Genome Med, 4(10), 77.

Wang, Y., Kuo, S., Shu, M., Yu, J., Huang, S., Dai, A., Two, A., Gallo, R. L., & Huang, C. M. (2014, Jan). Staphylococcus epidermidis in the human skin microbiome mediates fermentation to inhibit the growth of Propionibacterium acnes: implications of probiotics in acne vulgaris. Appl Microbiol Biotechnol, 98(1), 411-424.

Zhou, L., Chen, L., Liu, X., Huang, Y., Xu, Y., Xiong, X., & Deng, Y. (2022, Mar). The influence of benzoyl peroxide on skin microbiota and the epidermal barrier for acne vulgaris. Dermatol Ther, 35(3), e15288.


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