Benzoyl Peroxide: Benefits and How to Reduce Its Irritation

by | Last updated Mar 14, 2021 | Acne, Ingredients | 60 comments

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Benzoyl peroxide, a.k.a. the Acne Killing King. And uh, the thing that leaves your towel and pillow cases looking like this….

benzoyl peroxide towel

Sigh, it’s true. This acne killing machine does unfortunately cause bleaching if it comes into contact with WET fabric. As an aside, benzoyl peroxide resistant towels and sheets can be found at your local target (check the dorm section). Them college breakouts though…..

It’s one of the most powerful acne treatments available today, and its efficacy has withstood the test of time, with studies dating back 50 years. (1) Cooler yet, there has not been a single known instance of microbial resistance to benzoyl peroxide despite its use in dermatology since the early 1900s!

Today we’ll be discussing all the things science and benzoyl peroxide. Make sure to stick around for the secret tips on how to reduce its irritation. 

What is Benzoyl Peroxide? benzoyl peroxide

Benzoyl Peroxide (BP) is an organic compound and antibacterial ingredient used in acne medications. Besides it’s antibacterial properties, it’s also an effective comedolytic and keratolytic agent, meaning it unclogs pores and sloughs off dead cells (i.e. corneocytes).(23) Unlike antibiotics, it does not produce bacterial resistance. (4, 567)

It’s the second most prescribed acne medication in the United States (given in 12.8% of all cases), (8) and can be found over the counter in concentrations ranging from 2.5% to 10%.

Pro-tip: use 2.5%. Studies have shown it’s as effective as 10% with less irritation.

In my humble opinion, it is the most effective treatment against acne (besides accutane), and what I personally use to keep my skin clear! 🙂

It can reduce cutibacterium acnes (i.e. acne causing bacteria) by up to 97.5% in just 5 days. (9) In fact, benzoyl peroxide has the broadest spectrum microbicidal activity of any acne medication today — effective against cutibacterium, staphylococcus, malassezia, pseudomonas, and candida (among other species).

Fun fact: the in vitro microbicidal activity of benzoyl peroxide shows its most potent and rapid action is actually against malassezia versus cutibacterium and staphylococcus. That means BP is more effective as an anti-fungal than it is a bactericide, which explains why studies have shown it helps seborrheic dermatitis. (10)

The difference however, is very slight. Only 0.25 BP (mmol/L) is needed to inhibit malassezia, whereas 0.50 BP (mmol/L) is needed to inhibit cutibacterium and staphylococcus. (11) At the end of the day it’s still VERY effective against all three, meaning BP kills every major microorganism involved in the formation and / or exacerbation of acne. (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)

Benzoyl Peroxide Side Effects.

Unfortunately benzoyl peroxide can be pretty irritating. One study found it caused contact dermatitis, or dry-red-itchy peeling skin in 67% of benzoyl peroxide users. (29) It’s also known to induce erythema (redness), and increase sun sensitivity. (30)

The takeaway here is that it will make your skin drier than the turkey I made last thanksgiving (I’m a terrible cook, so that means VERY dry). However, there are some secret ways to minimize irritation without reducing its awesome acne fighting prowess. 😉

How to Reduce Benzoyl Peroxide Irritation.

Time for the juicy secrets! There are 3 ways of doing this:

1. Buffer it with a moisturizer.

In other words, apply your moisturizer first and then layer Benzoyl Peroxide on top of it. This only slightly decreases its effectiveness, and helps reduce redness and dry skin.

2. Short contact therapy.

Generally, when people use benzoyl peroxide they leave it on overnight or throughout the entire day, which could unfortunately cause irritation. Doing this might be unnecessary altogether.

One study examined the effectiveness of washing off benzoyl peroxide after a two minute application. (31) The researchers ended up ruling that it was “highly effective in reducing the quantity of P. acnes,” and comparable to a “leave on” 5% benzoyl peroxide product. Best of all, it didn’t irritate the skin!

3. Use a micronized benzoyl peroxide product!

Malezia Acne Treatment Gel

Micronization is the process of milling down the average diameter of a solid material’s particles. Malezia’s acne treatment gel, for example, has an average particle size of 5 microns — that’s smaller than the size of a bacteria cell!

This is important because homogenous dispersions of finer particles have proven to yield better results in fighting acne with less risk of irritation. In fact, one study found micronized benzoyl peroxide actually INCREASED skin moisture! (32)

Alrighty. That does it for Benzoyl Peroxide, folks. Hope you’ve enjoyed this!



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