Confused About Acids in Your Skincare? Top Dermatologists Share a Breakdown

When you think of acid hitting the skin, it may conjure up gruesome flesh-burning images. But when acids are infused into skincare products in small doses, these powerful ingredients can help solve your greatest skin concerns.

If you’re a skincare junkie, you’ve surely seen the words "salicylic" or "glycolic" splashed across labels on facial cleansers and moisturizers. They may sound like something straight out of a science experiment, but learning exactly how these acids work will help enhance your daily skincare routine.

As is the case with any hero ingredient, every acid serves a specific purpose, targeting distinct problem areas. When it comes to skincare products, hydroxy acids are the most widely used, and there are two common forms. First, there are alpha hydroxy acids, which are derived from foods such as citric fruits and help exfoliate the skin. And then there are beta hydroxy acids, which are similar to AHAs, but are oil-soluble instead of water-soluble. There are also collagen-boosting retinoids like retinoic acid, and brightening acids like azelaic. Have we lost you yet? No worries. 

To make sure you’re getting the very best results for your unique skincare concerns, we enlisted the help of top dermatologists to give us the lowdown on some of the most common acids on the market.

If dry skin is your concern, this moisture-boosting acid is going to be your savior, especially during the upcoming winter months. "Hyaluronic acid is like a sponge that pulls in hydration to the outer skin layer,” explains Dr. Joshua Zeichner, the director of cosmetic and clinical research at Mount Sinai Hospital in New York City.

In addition to being ideal for those with dry skin, Dr. Zeichner adds that this alpha hydroxy acid has a "plumping effect that can minimize the appearance of fine lines and wrinkles.” That's why this acid, most commonly found in moisturizers, is recently being used as a primary ingredient in skin-plumping products as well.

Dermatologist Recommended: Neutrogena Hydro Boost Water Gel, ($19.99)

Here’s one you’ve probably seen hundreds of times in the aisles of your favorite drugstore. This beta hydroxy acid, usually extracted from willow bark, has multiple skin benefits, which makes it great not only as an exfoliant, but as an acne treatment as well.

"Salicylic acid penetrates deeper into the pores than the alpha hydroxy acids, which is why many acne products in particular contain this ingredient,” explains Dr. Ted Lain, a dermatologist in Austin, Texas. Salicylic acid softens keratin, which Dr. Lain shares is the skin protein that acts as cement, binding dead skin cells together. "By exfoliating on the skin’s surface and within the pores, salicylic acid helps to prevent the formation of blackheads,” he notes. "Since blackheads are the precursors for all other acne blemishes, salicylic acid improves all types of acne."

In addition to treating blackheads, Dr. Lain shares that salicylic acid also helps decrease the redness and swelling of pimples, making it the ultimate acne weapon. According to Dr. Lain, it works best for normal to oily skin types.

Dermatologist Recommended: Mario Badescu Acne Facial Cleanser, ($15)

Glycolic acid is an alpha hydroxy acid that exfoliates dead cells from the surface of your skin, leaving you with a natural glow. Dr. Zeichner shares that it works best for people with dull or mature skin, as the "exfoliating process helps to stimulate collagen and strengthen the skin foundation." And while exfoliators may sometimes be rough on the skin, this sugarcane-derived acid is gentle enough to be used on all skin types, even sensitive skin.

"Glycolic acid is water-soluble, which means that it does not penetrate deep into the follicles the way its cousin salicylic acid does," Dr. Zeichner says.

Dermatologist Recommended: NeoStrata Foaming Glycolic Wash, ($40)

Citric acid, another exfoliating alpha hydroxy acid, is derived from citrus fruits. “Citric acid breaks down the bonds between skin-dulling dead skin cells on the surface of the skin to promote a more even, brighter complexion,” shares Dr. Annie Chiu, a board-certified dermatologist based in North Redondo Beach, California. "In skincare, it is mostly used for light exfoliation without obvious peeling or harsh scrubbing, and prevents further buildup of dead skin that can clog pores."

Dr. Chiu also says that is best for those struggling with discoloration, pigmentation, or dull skin. However, if you have sensitive skin, it can cause irritation and stinging.

Dermatologist Recommended: Ole Henriksen Face the Truth Gel Cleanser, ($24)

“Lactic acid is an alpha hydroxy acid found in sour milk,” explains Dr. Lain. As with salicylic acid and glycolic acid, it also works by softening keratin on the skin. "By helping remove the dead skin cells and excess keratin, lactic acid allows for reduction in scaliness, leaving the skin smoother and healthier,” Dr. Lain describes.

Since it is a deep exfoliant, lactic acid is often found in face peels. However, Dr. Lain says it is also gentle enough to be used at home or within a daily moisturizer. Still, those prone to very dry and sensitive skin should use with caution.

Dermatologist Recommended: Olga Lorencin Lactic Acid Hydrating Serum, ($79)

While not classified as a hydroxy acid, azelaic acid is another common acid with many skin benefits. "The original idea for using azelaic acid in skincare came from a common fungal infection of skin," shared Dr. Karyn Grossman, a board certified dermatologist specializing in cosmetic dermatology in Santa Monica, California, and New York City. While using the acid as a treatment, people noticed the area of the affected skin often turned lighter, which is why it can be found in many acne and rosacea treatments today. "It is a tyrosinase inhibitor, which means that it decreases melanin in the skin. Thus, it can help improve increased pigmentation from acne or melasma, and is also helps to normalize the production of keratin in skin," Dr. Grossman says.  

Azelaic acid also has a mild anti-bacterial effect and anti-inflammatory properties, therefore Dr. Grossman recommends it for those with rosacea and acne-caused pigmentary issues.

Dermatologist Recommended: Eau Thermale Avène Antirougeurs FORT Relief Concentrate, ($49)

Retinoic acid is a type of retinoid derived from vitamin A. According to Dr. Ellen Marmur, a dermatologist based in New York City, it helps to normalize skin turnover and works best for those struggling with acne. "Retinoic acid is most dramatic for acne-prone skin. It softens the skin, releases the trapped keratin, reduces the formation of blackheads, and eventually reduces the breakouts," said Dr. Marmur.

Dermatologist Recommended: SkinBetter Alpharet, ($110)

See? Nothing to fear!