There Is No Compelling Evidence of This to Date
The Essential Info
Benzoyl peroxide is a widely used and effective acne treatment that kills acne bacteria and unclogs skin pores. Although some people claim that benzoyl peroxide can increase hyperpigmentation (red/dark marks left after acne heals), the evidence that we have, while still weak and preliminary, would lead us to believe it does not in fact worsen hyperpigmentation.
It is possible that in rare cases, benzoyl peroxide might trigger skin irritation that could potentially result in worsened hyperpigmentation. Individuals with darker skin might be at greater risk of this unlikely side effect.
Dryness Can Lead to Temporarily Darker Skin: Many people over the years have emailed me saying benzoyl peroxide is giving them a “tan” or making their skin darker. This is due to what is called the “hardening effect” of benzoyl peroxide. Benzoyl peroxide comes with a lot of dryness for the first month or so until the skin becomes accustomed, or “hardened” to it. This dryness can make the skin appear to have a “tan” or to look darker. This should not be confused with hyperpigmentation. It is simply temporary dryness that subsides after a month or so.
The Bottom Line: There is no evidence that benzoyl peroxide makes hyperpigmentation worse, and on the flip side, when it is used correctly it can completely eliminate acne, thus preventing future acne lesions and future hyperpigmentation. To be extra-safe, keep your skin out of the sun if you are prone to hyperpigmentation when using, or for that matter when not using, benzoyl peroxide.
Benzoyl peroxide is one of the most effective acne treatments on the market today. It works by killing acne bacteria and preventing the clogging of skin pores, and it may possess anti-inflammatory and antioxidant properties.1-3
Many acne sufferers, particularly those with darker skin, develop darkened spots at the sites of healed acne lesions. This is called post-inflammatory hyperpigmentation. Hyperpigmentation can take months or, in some cases, even years to clear up, although there are treatments that can help speed up the process.4,5
The Evidence on Benzoyl Peroxide and Hyperpigmentation
No clinical studies have directly investigated the link between applying only benzoyl peroxide to the skin and then testing for effects on hyperpigmentation. In other words, we have no trustworthy scientific data to show that benzoyl peroxide alone either does or does not worsen hyperpigmentation in people with acne.
The only scientific evidence we do have comes from:
- One case report (a description of interesting or unusual observations a doctor makes on one or a handful of patients): Scientists consider such reports a very weak type of evidence.
- One rigorous clinical study (a study in which researchers set out to test a specific treatment on a large number of patients): Scientists consider such studies reliable. However, the issue with this study is that the researchers were looking at a combination treatment, so benzoyl peroxide was not the only drug the patients used. In other words, this study does not give us any clear idea about what would happen if patients used benzoyl peroxide by itself.
But since this is all we have to go on, let’s have a look at the evidence and see what we can discern. Let’s take a look at the case report first.
Some very weak evidence that benzoyl peroxide might trigger hyperpigmentation in special cases not related to acne
In this case, doctors observed unusual hyperpigmentation on the chest of two black men who had been applying 5% benzoyl peroxide to treat acne. The men first developed a rash on the chest and, after they stopped benzoyl peroxide treatment, the rash converted into a network pattern of hyperpigmentation (expand the drawer below to see). The doctors concluded that benzoyl peroxide irritated the patients’ skin, triggering a rash and, later, hyperpigmentation.6
It is important to note that the pattern of hyperpigmentation in these two patients looked very different from what normally occurs with acne. In other words, these were two very unusual cases, and no other doctors have reported on anything similar happening with their patients.
Expand to read details of case report
Now, let’s look at the clinical study, in which doctors treated acne sufferers with benzoyl peroxide in combination with another drug.
Some evidence that benzoyl peroxide does not trigger hyperpigmentation
A recent study that tested a treatment containing 2.5% benzoyl peroxide together with another topical medication (adapalene) on black patients and found no hyperpigmentation resulting from the treatment in any of the patients.7 Since the study was highly rigorous, this result is encouraging. However, because the treatment contained another drug in addition to benzoyl peroxide, we cannot be absolutely certain that benzoyl peroxide alone would have produced the same results.
Expand to read details of study
The verdict on benzoyl peroxide and hyperpigmentation
To sum up, until researchers conduct a large-scale study looking specifically at applying only benzoyl peroxide to the skin and its effects on hyperpigmentation, we will not know for sure whether benzoyl peroxide might make hyperpigmentation worse, but the evidence thus far points toward benzoyl peroxide not being a factor in this area.
Is it even theoretically possible that benzoyl peroxide could cause such a problem?
To understand how benzoyl peroxide might theoretically increase hyperpigmentation, we need to understand why hyperpigmentation occurs in people with acne in the first place.
What causes hyperpigmentation in acne?
Hyperpigmentation in acne is somehow linked to inflammation. Inflammation, which is part and parcel of acne, triggers a chain of events that can result in darkened spots, particularly in darker-skinned people. We do not know exactly how this occurs.
Scientists speculate that, in some cases, benzoyl peroxide might theoretically cause extra inflammation, and in that way potentially make hyperpigmentation worse. Keep in mind that this is all speculation at this point. But how would it even work?
Why might benzoyl peroxide cause additional inflammation?
The evidence on benzoyl peroxide and inflammation is contradictory.
On the one hand, some research suggests that benzoyl peroxide reduces inflammation in people with acne.3 This would imply that benzoyl peroxide should improve hyperpigmentation rather than make it worse.
On the other hand, some researchers have found that benzoyl peroxide can occasionally cause skin inflammation, resulting in skin redness, dryness, and scaling.8 Such a reaction to benzoyl peroxide is relatively rare and affects approximately 1 out of every 500 individuals.2 In other words, in a very small number of people, benzoyl peroxide can trigger a strong inflammatory reaction, which might, in theory, make hyperpigmentation worse.
In summary, while there is no direct evidence that benzoyl peroxide can increase hyperpigmentation, it is possible that such a side effect might occur in rare cases.
How Common Is Hyperpigmentation in Acne?
How Does Hyperpigmentation Occur?
Other Causes of Hyperpigmentation
Other Side Effects of Benzoyl Peroxide
The Bottom Line
Benzoyl peroxide is a widespread and effective topical treatment for acne. Despite a few claims online that benzoyl peroxide can make hyperpigmentation worse, there is no reliable evidence that this actually occurs. We will monitor new research as it comes out, but for now, there is no reason for concern.
- Sawleshwarkar, S. N., Salgaonkar, V. & Oberai, C. M. Multicenter study to evaluate efficacy and irritation potential of benzoyl peroxide 4% cream in hydrophase base (Brevoxyl) in acne vulgaris. Indian J Dermatol Venereol Leprol 69, 19 – 22 (2003). https://www.ncbi.nlm.nih.gov/pubmed/17642816
- Decker, A. & Graber, E. M. Over-the-counter Acne Treatments: A Review. J Clin Aesthet Dermatol 5, 32 – 40 (2012). https://www.ncbi.nlm.nih.gov/pubmed/22808307
- Draelos, Z. Irritation Profile of Benzoyl Peroxide Acne Washes: Impact of Formulation. Cosmet Dermatol 23, 541 – 547 (2010). https://www.mdedge.com/dermatology/article/69908/acne/irritation-profile-benzoyl-peroxide-acne-washes-impact-formulation
- Patel, A. B. Postinflammatory hyperpigmentation: Review of pathogenesis, prevention, and treatment. Pigment Int 1, 59 – 69 (2014). http://www.pigmentinternational.com/article.asp?issn=2349-5847;year=2014;volume=1;issue=2;spage=59;epage=69;aulast=Patel
- Davis, E. C. & Callender, V. D. Postinflammatory hyperpigmentation: a review of the epidemiology, clinical features, and treatment options in skin of color. J Clin Aesthet Dermatol 3, 20 – 31 (2010). https://www.ncbi.nlm.nih.gov/pubmed/20725554
- Weinberg, J. M., Moss, T., Gupta, S. M., White, S. M. & Don, P. C. Reticulate hyperpigmentation of the skin after topical application of benzoyl peroxide. Acta Derm Venereol 78, 301 – 302 (1998). https://www.ncbi.nlm.nih.gov/pubmed/9689304
- Lawson, C. N. et al. Updates in the understanding and treatments of skin & hair disorders in women of color. Int J Womens Dermatol 3, S21 – S37 (2017). https://www.ncbi.nlm.nih.gov/pubmed/28492036
- Foti, C. et al. Contact dermatitis to topical acne drugs: a review of the literature. Dermatol Ther 28, 323 – 329 (2015). https://www.ncbi.nlm.nih.gov/pubmed/26302055
- Grimes, P. E. Management of hyperpigmentation in darker racial ethnic groups. Semin Cutan Med Surg 28, 77 – 85 (2009). https://www.ncbi.nlm.nih.gov/pubmed/19608057
- Felton, S. J., Orton, D. & Williams, J. D. Benzoyl peroxide in topical acne preparations: an underreported contact allergen? Dermatitis 24, 146 – 7 (2013). https://www.ncbi.nlm.nih.gov/pubmed/23665828
- Kim, C., Craiglow, B. G., Watsky, K. L. & Antaya, R. J. Allergic Contact Dermatitis to Benzoyl Peroxide Resembling Impetigo. Pediatr Dermatol 32, e161 – 162 (2015). https://www.ncbi.nlm.nih.gov/pubmed/25782705