Glycolic acid is one of those ingredients that fall into the “oldie but goodie” category of skincare superstars. 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 cosmetologists and dermatologists for its long list of proven benefits. And, surprisingly, those benefits aren’t limited to exfoliation. Ahead, skincare experts explain exactly what makes this acid so unique and why it deserves a role in your skincare routine.

What Is Glycolic Acid?

Glycolic acid is an alpha-hydroxy acid derived from sugarcane. Because it comes in various strengths, it has various applications, ranging from over-the-counter, leave-on creams to medical-grade. 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.

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 (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.
• 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.

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. So, 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 equal, so your best bet is always to follow the directions for the particular product you’re using. 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 this figure isn’t a true indicator of how strong or effective it will be. 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. However, 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.