AHA vs BHA vs LHA vs PHA: The Difference between Exfoliating Acids in Skincare

by | Jun 10, 2020 | Blog, Dermatologist, skincare



AHA vs BHA vs LHA vs PHA: The Difference between Exfoliating Acids in Skincare

There are many products on the market used to exfoliate the skin. This is helpful because the skin’s ability to do so naturally on its own slows down as we age. AHA and BHA are among the most touted chemical exfoliants, while LHA and PHA are newer on the scene. They help shed the old, dead skin cells to transform skin from dull to radiant. However, each of these acids caters to people with particular skin types. We hope that this guide helps you identify which of these ingredients will be most effective for targeting your skin concerns.

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AHA stands for alpha hydroxy acids, which is a group of acids that includes glycolic acid, lactic acid, tartaric acid, citric acid, malic acid, and mandelic acid. It is useful in people with dry, rough skin such as in keratosis pilaris. AHA is water soluble and acts on the skin’s surface. It acts as an exfoliator and retains water in the skin. Glycolic acid is one of the most well known AHAs in skincare. Exfoliating with glycolic acid will help address sun damage by evening out the skin and softening fine lines and wrinkles. It exfoliates by triggering skin cells to self-destruct in a process known as apoptosis. Be sure to use sunscreen because exfoliating with glycolic acid makes the skin more sensitive to sun.


BHA stands for beta hydroxy acids, which is a group of acids that includes salicylic acid and some forms of citric acid. It is useful in people with oily skin. BHA is fat soluble and penetrates the skin more deeply than AHA to unclog pores and decrease oil production. Clearing out the pores will help reduce the appearance of enlarged pores. Salicylic acid in particular is most commonly known for its ability to treat acne and help with blackheads. In addition, salicylic acid can treat calluses and warts. It exfoliates by loosening the bonds between dead skin cells. Unlike glycolic acid, salicylic acid has been shown to exhibit sun protective abilities.

LHA stands for lipo hydroxy acids, which are derived from salicylic acid and have a similar purpose. They are more fat soluble than BHA and more gentle because they penetrate the skin more slowly. Therefore, they are useful for exfoliating and treating acne in those with sensitive skin. LHA may also augment the anti-aging effects of tretinoin, an active form of vitamin A, by stimulating skin cell production.


PHA stands for poly hydroxy acids, which is a group of acids that includes gluconolactone, lactobionic acid, and maltobionic acid. PHA is useful for people with sensitive skin such as rosacea or eczema because they are have larger molecular structures compared to AHAs. As a result, they penetrate the skin less and work more slowly. They also retain moisture and gently exfoliate the skin. Thus, PHA can provide visible improvements in sun-damaged skin comparable to AHA. Unlike AHA, PHA does not make the skin more sensitive to sunlight.

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Therefore, AHA is most helpful in people with dry, rough skin while BHA is most helpful in people with oily skin. People with sensitive will want to turn towards PHA. AHA, BHA, and PHA can also be mixed for those with combination skin types. Exfoliating with acids should be done at most two to three times per week (once or twice per week for those with sensitive skin). Signs of over-exfoliating include irritation, redness, peeling, and/or sensitivity to other skincare products. Caution should be exercised when using acids around eyes and neck since acids may be too strong for the skin in these areas. Since retinoids and acids are both exfoliating, these ingredients should not be used simultaneously.

If you have noticed a persistent issue or anything else that is suspicious on your skin, then we would recommend consulting a dermatologist for a closer examination. Here at First Derm, we have online board-certified dermatologists ready to take a look at your skin concerns. Simply upload an image anonymously and we’ll do the rest!

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