Benzoyl peroxide is an active ingredient used in many prescription and over-the-counter acne treatments. It kills p. acnes, the bacteria that causes acne. By killing the bacteria, you eliminate a major cause of frequent breakouts. Some experts classify benzoyl peroxide as a topical antibiotic, but many dermatologists use benzoyl peroxide to help enhance the performance of other topical antibiotics like clindamycin and erythromycin. Because benzoyl peroxide is primarily used to kill bacteria, it is most effective on inflammatory acne.
Although we don’t fully understand the mechanisms of how benzoyl peroxide works, we do know that it seems to kill bacteria by adding oxygen to the skin. When benzoyl peroxide is applied to the skin, it breaks down into two parts- oxygen and benzoic acid. Since the p.acnes bacteria thrives in an oxygen free environment, adding oxygen to the skin essentially kills off the bacteria.
I’ve heard many people complain that benzoyl peroxide seems to stop working. I used to think that you could develop a resistance to benzoyl peroxide, as consistent use would eventually cause more resistant bacteria (think: MRSA and other super bugs). But while researching this article, I’ve learned that, while there is concern about resistant p. acnes bacteria, benzoyl peroxide appears to be the solution, rather than the cause. Many researchers feel that the resistance comes from ingredients like clindamycin and erythromycin, and that benzoyl peroxide lessens that likelihood.
Benzoyl peroxide has some other functions that can be helpful for acne control. It also works as an exfoliant, helping to unclog pores and reduce the appearance of blackheads. I feel that benzoyl peroxide is not as effective at unclogging the pores as salicylic acid, so if you have a lot of blackheads, you may want to introduce that ingredient into your routine.
Benzoyl peroxide comes in all forms. You can find it in cleansers, spot treatments, moisturizers, and serums. If you’re using a wash, you can leave the cleanser on your skin for a few minutes as a mask. If using a serum, it can be applied all over the skin or just on spots. You can even just treat the areas of the face that break out the most often. You can find it in strengths from 2.5% to 10%, though many studies have shown that higher percentages are no more effective than lower ones, but higher percentages often cause more adverse reactions, such as redness, flaking, and dryness.
Though this ingredient can be very effective, like many ingredients, benzoyl peroxide has its downside. I find that many of my clients react adversely to benzoyl peroxide, more so than other common acne treatments. I’ve even found that people can use benzoyl peroxide for years before suddenly developing adverse reactions. Because of this, I like to recommend that you limit your usage as much as possible. If you have been using it twice daily, try cutting your usage down to once a day once your skin starts to clear. If you remain breakout free, try going to every other day. Eventually, you may be able to stop using benzoyl peroxide entirely. Or you find that you need to stay on a routine that uses benzoyl peroxide just a few times a week.
It’s also important to remember that benzoyl peroxide includes…peroxide. This means that it will bleach clothing, sheets, and towels. It is one of the biggest complaints about benzoyl peroxide, but it’s also the easiest to fix. You can get some cheap white pillow cases or towels to use. If you’re applying it to the body, apply it at night and wear inexpensive white tee shirts to sleep. Also keep in mind that if you’ve tinted your brows or lashes, benzoyl peroxide may cause the tinting to fade faster.
If you’ve been using benzoyl peroxide and you’re suffering from adverse reactions, I have a few ideas. First, try using a lower percentage. Research shows that lower percentages are just as effective as higher ones and equally effective. Less isn’t always more when it comes to skin, so don’t worry about backing off a little. Next, try using the benzoyl peroxide less frequently. If you’re using it twice a day, try once. Once a day, try every other day. If cutting the number of applications down doesn’t work, try a light weight, oil free moisturizer underneath your benzoyl peroxide product. Finally, if these tips don’t work, try something that stays on the skin for a shorter period of time, like a wash just a few times a week. You’ll still get the bacteria eliminating benefits without as much irritation.
A final thought to keep in mind. Benzoyl peroxide and retinol don’t mix. If you’d like to use both ingredients, make sure that you use one in the morning and one at night. It will help to minimize irritation, as well as maintaining the integrity of the individual ingredients.