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Glycolic acid is one of those ingredients that falls into the "oldie but goodie" category of skincare superstars, one that is often found in our favorite exfoliators. While it's by no means the newest or trendiest ingredient out there—it's been used in dermatology for over three decades—it is a tried-and-true staple, favored by dermatologists for its long list of proven benefits. And, surprisingly, those benefits aren't limited to exfoliation. Ahead, dermatologists explain exactly what makes this acid so unique and why it deserves a role in your skincare routine.
Meet the Expert
- Kenneth Howe, MD, is a board-certified dermatologist, who specializes in facial aesthetics and rejuvenation at Union Dermatology in Manhattan.
- Kavita Mariwalla, MD, is a New York-based dermatologist.
Keep reading to learn more about the benefits of glycolic acid.
Glycolic Acid
Type of Ingredient: Alpha-hydroxy acid
Main Benefits: Acts as a chemical exfoliant by loosening the bonds between dead skin cells while helping to treat acne. Glycolic acid also stimulates collagen production and acts as a humectant, attracting moisture to the skin.
Who Should Use It: Glycolic acid is well-tolerated by most skin types and is gentle enough that usually, even those with sensitive skin can use it, says Howe.
How Often Can You Use It: This depends largely on your skin and the particular product you're using, but in certain situations, it can be used daily.
Works Well With: Other humectants, such as hyaluronic acid, though it's also often combined with lightening ingredients such as kojic acid or hydroquinone.
Don't Use With: Be especially cautious when pairing it with other acids and retinoids, cautions Mariwalla.
What Is Glycolic Acid?
"Glycolic acid is an alpha-hydroxy acid derived from sugarcane," explains Howe. Because it comes in various strengths, it has various applications, ranging from over-the-counter, leave-on creams to medical-grade, chemical peels that only dermatologists should apply, adds Mariwalla. Looking at the big picture of all of the different types of acids out there, it falls on the gentler end of the spectrum, which is what makes it a good option for almost anyone. However, as far as AHAs specifically go, it's one of the stronger, more potent ones; because it has the smallest molecular weight of any alpha-hydroxy acid, it penetrates the skin more easily, explains Howe. In other words, it's more effective than other common AHAs such as lactic acid or malic acid, though subsequently not quite as gentle.
Benefits of Glycolic Acid for Skin
Essentially every acid acts as a chemical exfoliant, but glycolic acid has several other notable attributes.
- Removes dead skin cells to reveal softer, smoother skin: Glycolic acid works by loosening the binding between dead skin cells, allowing them to slough off, says Mariwalla. (If you want to get technical, the term for this is desquamation).
- Is an effective acne-fighter: By encouraging the shedding or peeling of cells on the skin's surface and those lining the pores, glycolic acid prevents the formation of clogged pores—the main factor that contributes to acne, says Howe.
- Works deeper in the skin to stimulate collagen production: Glycolic acid's effects aren't limited to the skin's surface. It's also been found to work on the skin's deeper layers to promote collagen synthesis, which is why it's considered a good anti-aging ingredient, Howe says. (Mariwalla notes, however, that, unlike its exfoliating effects, the youth-boosting benefits come with continued use over time. In other words, while you'll see smoother, more even skin pretty much instantly, it'll take time to notice an improvement in lines and wrinkles).
Side Effects of Glycolic Acid
At the end of the day, an acid is an acid. And that means that there's always going to be the potential for some redness, irritation, and peeling, particularly if your skin is sensitive to start. (Howe says that those who are eczema-prone or have a dehydrated complexion are especially at risk).
How to Use It
Not all glycolic acid products are created equally, so your best bet is always to follow the directions for the particular product you're using, whether it's a peel or something like this glycolic acid toner from the Ordinary. Some rely on glycolic acid alone, though many pair it with other acids specially formulated to not irritate. It's also worth noting that, even if a product specifies a concentration of glycolic acid (most OTC options contain less than 1 percent), this figure isn't a true indicator of how strong or effective it will be, says Mariwalla. "That's determined by the free acid value, which has to do with both the amount of glycolic acid and the pH of the product, and often isn't listed," she says. If you want to err on the side of caution, stick with products that contain less, but keep in mind, it's best to start using glycolic acid gradually and build up frequency as your skin adapts. Reserving application for your nighttime routine is also a good approach since it may make your skin more sensitive, Mariwalla adds.
