Beta Hydroxy Acid for the Skin

BHA serum dropper bottle

A few weeks ago, we wrote about the benefits of AHAs, aka alpha hydroxy acid, for the skin. This week we’re visiting a similar topic—beta hydroxy acids.

This week’s blog post will hopefully clear up some questions you may be having. What are the differences between AHAs and BHAs? What are the different (and similar) skin care benefits? Where does BHA even come from?

Read on and we’ll answer all these questions and more.

A white dropper and bottle with BHA serum

What are Beta Hydroxy Acids – BHAs? 

This you probably know already: beta- and alpha- are both forms of hydroxy acids, a natural, oxygen and hydrogen-based compound. The chemical difference between the two is that alpha hydroxy acid has one carbon atom between the ‘hydroxy’ and ‘acid’ parts of the molecule, and beta hydroxy acid has two. So while they’re very similar down to their chemical makeup, the difference does result in some varying functions and benefits.

However, this remains the same: both AHA and BHA are chemical exfoliants that work by loosening and scrubbing away unwanted things on your skin like dirt, bacteria, and removing dead skin cells. The chemical difference in BHAs actually make them oil soluble, unlike water-soluble AHAs. This means that BHAs can better penetrate deeper into the skin, providing a more thorough exfoliation.

You can find BHAs listed on ingredient labels in a few different forms: salicylic acid (or salicylate, sodium salicylate, and willow extract); beta hydroxybutanoic acid; tropic acid; and trethoacanic acid. The form you will most likely see on labels though is salicylic acid, and it’s the form we’ll be most focused on.



Like AHAs, BHAs sound like something made in a lab underground somewhere. However, that isn’t the case! Salicylic acid, specifically, is a colorless acid derived from willow bark.

It is also closely related to a form of aspirin—yup, the over-the-counter medicine! Although they have a similar chemical composition, their effect on skin is different and aspirin should not be used as a DIY BHA. The main different is that Aspirin has an “acetyl group”. However, since they are related, salicylic acid is also on the World Health Organization’s list of essential medicines.

A willow tree next to a river

The benefits of BHAs

The use of BHAs in skincare is a more recent development than Alpha Hydroxy Acids AHAs, which have been used and studied more extensively for years. While they can be used in combination with AHAs, beta hydroxy acids are also effective treatments on their own.

As mentioned above, the chemical formation of BHAs allow for deeper penetration into the skin’s pores, and can truly clean them out, while AHAs are primarily active on the surface of the skin. That means if you’re looking for a deep clean, BHAs may be the right fit for you.

Inside your pores, BHAs act to dissolve whatever is clogging them, be it excess oil or dirt, and further have anti-inflammatory properties that assist in reducing those puffy red pimples we all hate.

In fact, BHAs are so effective at deep exfoliation that they can even break down the connection between skin cells, further promoting the turnover of dead cells. This, in turn, causes new, fresh skin cells to replace them, resulting in a more youthful glow, and reduces other signs of aging like fine lines and wrinkles.

If you’re someone struggling with acne and have breakout prone skin, BHAs may be the treatment you’ve been looking for. Note, however, that salicylic acid alone doesn’t have much in the way of antibacterial properties, so is best paired with a treatment that does.

After applying a BHA, be sure to follow up with a moisturizer and oil (like our Facial Recovery Elixir to capitalize on the benefits of BHAs), as they can be quite drying.

A woman in a bath tub full of orange and lemon slices

Just like AHAs, there can be downsides to BHAs. While the beta form is commonly thought of to be more gentle than their alpha counterparts, chemical exfoliation shouldn’t be in your routine daily. If you’re struggling with acne or congested skin, stick to three times a week.

In fact, the best use of BHAs are in targeted, acne-prone areas, instead of all over your face and body. It’s easy to get over excited, but this is one skincare product that should be used in moderation. This will help limit potential dryness, redness, and irritation that may occur. If you have especially dry or sensitive skin, you may want to avoid using this all together and swap for a gentle emollient like our Deeply Cleansing Milk.

In addition, the FDA has a particular call out on their website to increased sun-sensitivity, just like alpha hydroxy acids. The FDA suggests that products containing BHAs should either contain SPF or include label instructions advising people to use sun protection alongside it. This is why we suggest leaving chemical exfoliators to be night-use only, which will also be beneficial in hiding any irritation that may occur after use.



Swatching is a technique you should use before trying any new skincare product, but it’s especially pertinent to potential irritants like AHAs and BHAs. Before using it on your face, rub a small swatch of the product into the skin of your inner wrist. This part of your skin is similar in sensitivity to your face, so it’s a great place to test a new product.

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