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How Benzoyl Peroxide Works: Everything You Need to Know

How benozyl peroxide works and how to use it to get clear skin

If you’ve ever used an acne treatment, you’ve heard of Benzoyl Peroxide. This is one of the most common active ingredients in skin care treatments, often used alone or in combination with a topical antibiotic, reducing antibiotic resistance.

You can learn more about how to treat acne and how Benzoyl Peroxide fits into that routine. Note that when using Benzoyl Peroxide, you’ll get better results when using the ingredient consistently. This should be an every day ingredient, not only as needed.

How Benzoyl Peroxide Works in Skin Care

Kills Bacteria

We all have bacteria living on our skin, but if you suffer from a skin condition such as acne the kind of bacteria on your skin tend to be different, and those bacteria can be involved in the creation of blemishes. Use of antibiotics can help keep the bacteria under control, but over time resistance becomes a problem.

Benzoyl peroxide uses a reactive oxygen species (exactly what you’re trying to neutralize when you use an antioxidant) to kill bacteria. It is particularly effect against P. acnes and C. acnes, the 2 main bacteria involved with acne. Note that benzoyl peroxide is also frequently combined with topical antibiotics to overcome resistance to the antibiotic.

Keratolytic Activity

If you’ve read my acne guide, you learned all about how skin cells clump together, clogging the pore. Benzoyl Peroxide increases the rate that those skin cells declump. All of the dermatology books I’ve read describe this as aiding the process, not truly declumping the cells actively as they are doing this on their own.

Note that Salicylic Acid and Retinoids also have keratoylic activity, and in testing all three work to roughly the same degree, but the Benzoyl Peroxide seems to get there a little faster and also helps other active ingredients penetrate into the blemish.

Due to the declumping of the cells, blemishes are cleared from the skin more quickly.

Well Suited to treat Acne

While there are quite a few amazing ingredients to fight acne and treat blemishes, many of the ingredients have a hard time penetrating down into blemishes. Due to the large amount of sebum (oil) in the blemishes, ingredients need to be lipophilic (aka- oil loving, able to be absorbed by the oil) to get down into the blemish.

Benzoyl Peroxide is well suited for the lipid environment, it is able to penetrate down into blemishes and help other ingredients do so as well.

Be Careful Using Benzoyl Peroxide

Unfortunately, some of the things that make Benzoyl Peroxide so wonderful in skincare also make it harder to use.

Benzoyl Peroxide can absorb easily into your skin, eventually it is excreted into your urine. If your skin is dry or irritated (note, both things that Benzoyl Peroxide will increase), then absorption is even higher. Be sure to pay close attention to your skin while using Benzoyl Peroxide, and adjust accordingly. A little extra dry? Use a heavier moisturizer that night. More irritation than usual? Skipping treatment products for 1 night might be a good idea.

One final note, due to the absorption into your body, it is recommended to avoid Benzoyl Peroxide during pregnancy (read more about pregnancy safe skincare).

Make sure you check out the Best Benzoyl Peroxide Face Products

all about how zits start
Learn more in my Acne Guide

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About Me

I’m a doctor, a mommy and a bit of a beauty addict. If you let me, I can take 2 hours to get ready in the morning. Really. I'm on a quest for faster beauty that works!

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  1. 7.2.18
    Reema said:

    I use Humane Benzoyl Peroxide 10% Acne Treatment wash for my face and it’s controlled my acne 🙂

  2. 7.2.18
    Suzie said:

    Where do you buy it?

  3. 7.2.18
    Suzie said:

    Not sure, does this recommend putting all over face daily? Or just spot treatment on blemishes? I usually use rubbing alcohol to spot treat blemishes.

    • 7.2.18
      15mins said:

      Usually it’s recommended to use benzoyl peroxide daily all over, though note it is irritating, so you might need to try a lower concentration if you get a lot of dryness irritation. Low % all over every day, then a higher % as a spot treatment. Note rubbing alcohol likely dries things out, but doesn’t have specific anti-acne activity that I know of.

  4. 1.14.20
    Ariana said:

    Should I use spf before applying the benzoyl peroxide in the morning and another moisturizing cream that has 20% Vaseline at night?

    • 1.14.20
      15mins said:

      SPF should be the last step in your routine. At night I would put the 20% vaseline over BP, as it will prevent anything from penetrating.
      This will help: What order to apply your skincare