AHAs vs. BHAs—Here’s Everything You Need to Know About the Popular Chemical Exfoliants

May 20, 2021

If your complexion is in desperate need of a skin-smoothing radiance boost, the answer is simple: it’s time to exfoliate. But if the thought of scrubbing your face with one of those uncomfortable, gritty formulas of the past just sent shivers down your spine, don’t worry. There’s a whole new generation of exfoliants out there today that accomplish the same retexturizing and glow-boosting results without using those hash physical formulas of the past. They’re called chemical exfoliants, and if you’ve spent any time looking at skincare products recently, chances are you’re already familiar with the two most popular formulas: AHAs and BHAs.

Known as alpha- and beta-hydroxy acids, AHAs and BHAs are the gold standards of chemical exfoliation, which is to say, they’re your ticket to achieving a smoother, healthier-looking glow. But what exactly are these exfoliating acids, how do they work, and how do you know which one is ideal for your skin? To help get to the bottom of all of these questions and more, we tapped three of the industry’s leading dermatologists to break down everything you need to know about AHAs vs. BHAs and what it takes to master the art of the glow.

What are AHAs?

Alpha-hydroxy acids are a type of water-soluble acid typically derived from sugarcane or fruit sources, which is why they are often referred to as the “fruit acids,” explains board-certified dermatologist Dr. Rachel E. Maiman of Marmur Medical. While AHAs provide a wide range of benefits, their main objective is to help break up the bonds between dead skin cells that accumulate on the skin’s surface and gently exfoliate them away so that the complexion appears smoother, less mottled, and more radiant.

Types of AHAs

There are several different types of AHAs used in skincare. Here are some of the most popular ones that you’ll find in your go-to products:

Glycolic acid: This is the strongest and most commonly used AHA. According to Dr. Maiman, “because glycolic penetrates the deepest—and some studies suggest, into the dermis—it has shown to be the most effective at stimulating collagen production, thus promoting deeper wrinkle reduction.” As award-winning, NYC-based dermatologist Dr. Dendy Engelman explains, “it is also a great exfoliant that helps to accelerate cell turnover, which is why I generally recommend it for people who are concerned about skin dullness or signs of aging.”
Lactic acid: Naturally derived from milk, lactic acid is slightly gentler and more hydrating than glycolic acid, making it a better option for dry and sensitive skin types. “Lactic acid is also a great [ingredient] for brightening the skin and enhancing skin radiance,” adds Dr. Engelman.
Mandelic acid: Another mild AHA option, mandelic acid is derived from almonds and helps increase skin cell turnover. According to board-certified dermatologist Dr. Corey L. Hartman, it is an excellent option for treating hyperpigmentation.
Tartaric acid: An AHA commonly derived from grapes. Instead of acting as an exfoliant, it is more often used for its antioxidant and astringent healing properties in combination with other acids.
Citric acid: Though commonly used as a preservative in food products, citric acid is also a mild AHA that helps balance the skin’s pH levels and provides anti-oxidative benefits.

The Benefits of AHAs

As Dr. Hartman notes, the primary function of AHAs is to break apart the bonds that hold dead skin cells together, specifically at the outermost layer of the skin (known as the epidermis). Why is this important? As we age, our skin cell cycle naturally slows down, leading to a buildup of dead skin cells. Over time, this buildup can accumulate, causing our complexions to appear dull, rough, and uneven. “What AHAs do is they break down these bonds, thus loosening the dead skin cells and exfoliating them away,” says Dr. Hartman. “The result is skin that appears smoother, clearer, and more even.”

Not only do AHAs work to improve the texture of your skin by shedding dead cells on the surface, but according to Dr. Maiman, they can also address signs of aging. “AHAs, especially glycolic acid (as it penetrates the deepest), have been shown to stimulate hyaluronic acid, collagen, and elastin production in the skin, thus increasing the skin’s thickness and promoting a greater reduction in deep wrinkles,” she says. “Moreover, AHAs can also help reduce hyperpigmentation by dispersing pigment and accelerating skin cell turnover,” helping to reveal the younger, evenly-pigmented cells underneath.

Derm-Approved AHA Products

Here are some of our experts' favorite AHA skincare products:

ISDIN Night Peel: According to Dr. Maiman, ISDIN’s Night Peel is an effective and synergistic combination of glycolic, tartaric, and malic acids that stimulates gentle exfoliation and delivers an immediate glow with a very low risk of irritation. This peel is also gentle enough to be used daily.
Exuviance AP25 Performance Peel: “Exuviance makes a powerhouse of an at-home peel because it has a 25 percent blend of multiple AHAs, including glycolic and mandelic acid, plus gluconolactone,” says Dr. Maiman. “Gluconolactone is an exfoliant that results in a smoother and brighter complexion. However, unlike AHAs, it is a humectant, which means it helps skin hold onto water. As a result, it is a great supporting player to the more active AHAs in this product, as it improves tolerance and reduces the likelihood of irritation. I recommend using this peel twice a week as it’s a high concentration of glycolic acid.”

SkinBetter Science AlphaRet Overnight Cream: Another one of Dr. Maiman’s go-to AHA products, this night cream is technically a retinol but also features lactic acid, both of which are potent anti-aging ingredients. “The formula of the cream is chemically stable and non-irritating,” she adds. “When applied, the skin’s natural water content triggers a slow release of each active ingredient, making it less irritating to the skin, but without compromising efficacy. Because lactic acid is also a humectant that plays well with the other ingredients found in this cream (squalane, niacinamide, ceramides, and fatty acids), the skin remains optimally hydrated, helping to reduce the potential for irritation.”
SkinCeuticals Retexturing Activator: This gentle retexturizing serum is one of Dr. Hartman’s go-tos, especially for those with dry or sensitive skin. “I love this product because it contains glycolic acid but is also super moisturizing, and so it’s able to achieve results without any irritation,” he tells us. “I first started using it with my patients who could not deal with the peeling that would come when they first started using retinol. We found that this was actually a great hydrating serum that got rid of that scaly feeling they hated without irritating the skin. Now it’s one of my favorite products.”
La Roche-Posay Glycolic B5 Serum: For a more affordable option, Dr. Harman also suggests La Roche-Posay’s Glycolic B5 Serum, which he notes, combines glycolic acid with the antioxidant B5 to help soothe irritation and inflammation for healthier-looking skin.