Everything You Need to Know About Glycolic Acid, Explained

Deanna Pai
·8 min read

No hyperbole: Glycolic acid changed my life. After years of alternating between salicylic acid and benzoyl peroxide, brushing off flakes caused by retinol, and piling on pounds of concealer to cover an errant breakout, I was finally able to walk outside without makeup and not feel self-conscious about my acne-prone skin. If I were to get into the lobbying game, I would sell my soul for glycolic acid. Were I to run for president (of whatever), my slogan would be Glycolic Acid Deserves More Credit.

The major advantage of glycolic acid is that it does more than treat breakouts. The ingredient can also tackle hyperpigmentation, dullness, and signs of skin aging, such as lines and wrinkles, without breaking a sweat. But don't just take my word for it. Here's a breakdown of the most common questions about glycolic acid and what exactly makes it such a great ingredient.

What is glycolic acid?

Glycolic acid is a type of alpha-hydroxy acid (or AHA) that's derived from sugar cane. It joins other acids you might recognize, such as lactic acid (derived from sour milk and purportedly a favorite of Cleopatra's), tartaric acid (from grapes), and citric acid—which, you might guess, comes from citrus fruits.

But it's unique. “Of the AHAs, glycolic is the simplest in structure and the smallest; it has the lowest molecular weight,” says Kenneth Howe, M.D., a dermatologist at Wexler Dermatology in New York City. That small molecular weight means “it's easy for it to penetrate your skin and be super effective,” says Alix Shapiro, skin therapist at Heyday in NYC.

What does glycolic acid do for your skin?

First and foremost, glycolic acid is an exfoliant. It helps shed dead skin cells and reveal the newer, brighter layers underneath by acting on the stratum corneum (the outermost layer of skin). “Normal, intact stratum corneum consists of tightly packed layers of dead skin cells that are tightly bonded together," says Howe. "Glycolic acid loosens these bonds.” With their glue dissolved by glycolic acid, those tough, rough layers of dead skin cells can more easily slough away.

But because glycolic acid is so small, it can get deeper into your skin too, where it does some serious work. “Glycolic acid stimulates fibroblasts in the dermis to produce increased amounts of collagen,” says Howe. And by stimulating collagen production, it helps skin feel firmer and minimizes fine lines and wrinkles. Between the superficial action on your stratum corneum and the work it does below, “your skin will feel smoother and look more radiant and even-toned,” Shapiro says.

How do you use glycolic acid in your skin-care routine?

As with any exfoliant, it's best to start small if you have sensitive skin or are prone to irritation. For this, Shapiro recommends using it in a face wash. “A glycolic cleanser can get your skin used to it, rather than diving straight into a leave-on glycolic product if you are unsure whether your skin can tolerate it,” she says. Try one that pairs glycolic with hydrating ingredients, like Glow Recipe's Blueberry Bounce Gentle Cleanser, which includes hyaluronic acid.

Glow Recipe Blueberry Bounce Gentle Cleanser

$34.00, Sephora

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Mario Badescu Glycolic Foaming Cleanser

$16.00, Mario Badescu

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Peter Thomas Roth 3% Glycolic Solutions Cleanser

$39.00, Peter Thomas Roth

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Innbeauty Project Foam Around Clarifying Daily Cleanser

$22.00, Innbeauty Project

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If you know your skin is up for glycolic, try it in a peel. “I feel glycolic acid is most effective when administered as a chemical peel done in a health care practitioner’s office,” says Howe. “The medical-grade peel pads we use are stronger, with more potent effects, and many people get better results with stronger treatments done intermittently—once a month, say.”

Obviously, getting to a derm every month isn't always in the cards, which is where milder forms exfoliation like at-home peel pads come in. These are products you can use more regularly in your routine—anywhere from twice a week to every other day if you know your skin can tolerate it. I personally swear by BeautyRx Advanced 10% Exfoliating Pads, while Dr. Dennis Gross Alpha Beta Universal Daily Peel has a cult following for delivering gentle but effective exfoliation.

BeautyRx by Dr. Schultz Advanced 10% Glycolic Acid Peel Pads

$70.00, Amazon

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Dr. Dennis Gross Skincare Alpha Beta Universal Daily Peel

$88.00, Dr. Dennis Gross Skincare

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The Ordinary Glycolic Acid 7% Toning Solution

$9.00, The Ordinary

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Alpha-H Liquid Gold Exfoliating Treatment with Glycolic acid

$48.00, Alpha H

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Is glycolic acid good for all skin types?

“It's best for normal, combination, and oily skin types,” says Shapiro. But as with anything, glycolic acid is not for everyone. “People with dry, highly sensitive skin often react to it with irritation," says Howe. "Any form might irritate them, whether it’s in a topical product, a home-use peeling pad, or an office-based peel procedure.”

There's also a seasonal factor to consider. In the winter, when your skin's barrier function might be compromised (and therefore skin appears dry or chapped), this can allow for deeper penetration and, in a nutshell, irritation. Conversely, sun exposure can increase the turnover of skin and therefore is naturally exfoliating. In the summer, that makes glycolic acid riskier, since it can make you sensitive to sunlight. (Although, no matter the time of year or where you're going, slathering on SPF is essential—especially after exfoliating.)

What should you not use glycolic acid with?

While glycolic acid can be beneficial in conjunction with other, gentler exfoliators like salicylic acid, combining it with more hard-core exfoliating ingredients is best avoided. That means any manual exfoliant (like a face scrub), benzoyl peroxide, and—depending on how well your skin can stand up to harsh products—retinol.

For example, if it took you weeks to acclimate to retinol burn, then adding glycolic acid on top of it is likely too much for you. And even if you do think your skin is tough, combining glycolic acid with retinol can still be problematic. “Retinol products speed up cell turnover in your skin, resulting in a functional exfoliating effect,” says Howe. “This thinning of the outer layer of your skin increases the penetration of glycolic acid, and with that the likelihood of irritation.”

One easy way to avoid a DIY disaster is to look for glycolic-based products that are formulated with a low percentage of other gentler exfoliants (like the Cane + Austin 5% Glycolic Acid and 2% Salicylic Acid Acne Retexture Pads and Pixi Beauty Glow Peel Pads, below) and stick to serums and moisturizers with hydrating ingredients like hyaluronic acid for the rest of your routine.

Cane + Austin Acne Retexture Pad

$60.00, Amazon

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Pixi By Petra Glow Peel Advanced Exfoliating Pads

$22.00, Amazon

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Starface Exfoliating Night Water

$12.00, Starface

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Moon Juice Acid Potion Resurfacing Exfoliator

$42.00, Moon Juice

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Is glycolic acid good for treating acne?

Yes, glycolic acid is a great choice for acne-prone skin, says Loretta Ciraldo, M.D., board-certified dermatologist and founder of Dr. Loretta Skincare. “It works by un-gluing dead skin cells from each other, which clears out your pores,” she says, adding that it's great for not only treating, but also preventing most types of acne like blackheads, whiteheads, and pimples, since the root cause is a build-up of oil.

However, approach with caution if you have dry skin, sensitivity, or cystic acne. “If you have a mild to moderate case of acne, you can use it and simply avoid it over areas that are already sensitive,” says Ciraldo. “But if you have rosacea or painful cystic acne, the acid may be too harsh. In these cases it's important to consult with a dermatologist or an experienced aesthetician.”

If you have moderate to advanced acne or are looking to lighten hyperpigmentation and scarring, Ciraldo recommends choosing a product with 10% glycolic acid—she likes her Micro Peel Peptide Pads or the L'Oréal RevitaLift 10% Glycolic Acid Resurfacing Serum. If you're sensitive or have more mild acne, go with a lower percentage.

Dr. Loretta Micro Peel Peptide Pads

$60.00, Dr. Loretta

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L'Oréal Paris Revitalift Derm Intensives 10% Pure Glycolic Acid Serum

$30.00, L'Oréal Paris

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Does glycolic acid have any side effects?

Since it's a powerful acid, you run the risk of skin irritation or burns. “But not what happened to Samantha in Sex and the City,” says Howe. “I have never seen a reaction that severe, not from glycolic acid.” Overall it's actually very safe, so much so that a derm can do a glycolic acid peel to treat acne during pregnancy.

Another advantage? It has a built-in safeguard. “Glycolic acid is immediately neutralized upon contact with water,” Howe says. Not only can you rinse it off if you feel tingling, but even if it penetrates deeply into your skin, it eventually reaches the water in the dermis. There it's neutralized and won't go any further.

Deanna Pai is a beauty writer in New York City. Follow her on Instagram @deannapai.

Originally Appeared on Glamour