Hello again everyone! I am continuing my “ABC’s” of skincare ingredients—next up, Beta Hydroxy Acids (BHAs). If you missed the last Beauty Nerd post about AHA’s, you can check it out here.
First, my disclaimer: Nothing I write in this series should be considered medical advice and I will be writing from the perspective of a consumer interested in understanding how products work and if they are effective. If you have any medical questions, you should talk to your doctor!
What are they?
In the skincare world, BHA is pretty much synonymous with salicylic acid. Salicylic acid can be synthesized in a lab, or extracted naturally from Willow Bark. So, when reading a label if you see either salicylic acid or Willow/Willow Bark extract, you are looking at essentially the same ingredient, functionally.
The “beta” in the name is really just a description for where the “hydroxy-“ groups (OH, or alcohol in the chemistry world) are in relationship to the “carboxyl” group (where both a hydroxyl group and a double-bonded oxygen are bonded to the same carbon). Just like “alpha” is the first letter of the Greek alphabet, the hydroxyl group in Alpha Hydroxy Acids are only one carbon away from the carboxyl group. In Beta Hydroxy Acids, they are two carbons away (beta being the second letter of the Greek alphabet).
If we get real technical from a Chemistry standpoint, salicylic acid isn’t a true Beta Hydroxy Acid because its hydroxy- group is located on what is called an aromatic benzene ring (though it is still two carbons away from the carboxyl) and has a different acid/base status than other “hydroxy acids”. I know this all sounds a little confusing, so let’s get into the practical cosmetic uses.
How do they work?
In low concentrations (4% or less, most commonly 1 or 2%) they are used in non-prescription topicals. Salicylic acid is especially helpful for acne-prone and oily skin types (versus AHAs) for two major reasons. First, salicylic acid is lipid soluble. Oils (like those naturally produced in your skin) are lipids, so that means that the salicylic acid’s actions will be able to penetrate and work effectively in the presence of the natural oils in your skin’s sebaceous glands. Through this mechanism, it has been found to actually reduce skin oil production. Salicylic acid is also known to be a natural antibacterial and antifungal agent. Much regular acne is caused by a bacteria present on the skin—P. vulgaris, so salicylic acne can help to treat and prevent acne by inhibiting the growth of those bacteria.
Salicylic acid also acts as an exfoliant by breaking down the bonds that hold skin cells at the outermost surface together, especially at higher concentrations. Dermatologists use it in the context of chemical peels to fade melasma, freckles, and post-inflammatory erythema and hyperpigmentation, as well as mild-to-moderate textural issues and fine lines. It has also been used in high concentrations to effectively treat warts.
Salicylic acid is a Pregnancy Category C, meaning that it is not recommended for use because risk at this point cannot be ruled out.
Salicylic acid contact allergies and sensitivity is relatively uncommon. However, it is recommended that those who have contact allergies to Aspirin not use Salicylic Acid since it is a related substance.
Like AHAs, Salicylic acid has the potential to increase sun sensitivity and use should be paired with daily sunscreen.
Where can I find them?
I personally use salicylic acid every other day in a spot treatment on active acne and in the areas that I tend to break out in (mostly my cheeks and the sides of my face). I found that it can be a bit too drying on my skin (dry and sensitive at the moment) when used everywhere or every day. When my skin was more combination-type, I found it even more helpful.
Here are some of the products that I have personally tried and can recommend. I’ve enjoyed all three products– though my favorite for my skin type is the Paula’s Choice. It is always recommended to start a new product with a week or two of patch testing on a non-facial area to check for reactions…though if I am honest I often skip this step (and have paid the consequences before). At the very least, whenever I start with a new product I will use it once every 3 days (instead of daily) to make sure that it doesn’t irritate my skin.
PS– if you are interested in purchasing the Paula’s Choice 2% BHA Liquid (or anything from their site), you can get $10 off your order using this link. This is not a sponsored post, but I enjoy their products and use their “Refer-a-Friend” program.