If you aren’t yet familiar with glycolic acid, it’s considered the gold standard of chemical exfoliants. Thanks to its ability to tackle everything from signs of aging to dullness and excess sebum production, dermatologists and skin experts alike have used glycolic acid in their facial and body-care routines for ages. But, in 2021, we raised an eyebrow when TikTok users started using glycolic acid for armpits — as a hack to replace deodorant.

Now, enthusiasts of the trend #glycolicacidasdeodorant love the star ingredient to also address concerns like underarm hyperpigmentation, so we knew it was time to investigate. But before we dive into whether glycolic acid has any skincare benefits for your pits, let’s get some glycolic acid 101 out of the way. 

What Is Glycolic Acid?

We already mentioned glycolic acid is a popular chemical exfoliant, but how does it work? Specifically, “it’s one of the smallest alpha-hydroxy acids — or AHAs — and a lower molecular weight than other acids, so it can penetrate the skin deeper and more efficiently," says Martha H. Viera, MD. "A substance derived from sugarcane plants, it weakens the bonds between skin cells and therefore works as an excellent exfoliant with minimal irritation. It’s also well-known for its ability to encourage collagen production to reveal healthier-looking skin."

Meet the expert

• Martha H. Viera, MD, is a board-certified dermatologist in Coral Gables, Florida.
• Jodi LoGerfo, DNP, is a dermatology nurse in New York City.

Can Glycolic Acid Double as Deodorant?

First, knowing the distinction between deodorant and antiperspirant is important, as people often use them interchangeably. In a nutshell, antiperspirant products address both sweat and odor, while deodorant only helps with the smell factor. “Glycolic acid won’t do anything for sweating less," says Jodi LoGerfo, DNP. "But since it’s acid with a lower pH than your skin, it might help ward off the bacteria in the armpit area that causes you to smell."

So, if you’re looking to reduce body odor in your underarm area, glycolic acid could do the trick — but if sweat is also an issue, you’ll still need an antiperspirant.  

The Benefits of Glycolic Acid for Armpits

In addition to tackling body odor, glycolic acid has other game-changing ways to help people’s underarm areas. If dark armpits are a concern, “glycolic acid helps exfoliate the top layer of cells, where, most of the time, darker pigment lays," says Dr. Viera. "It’s not a bleaching agent, but it’s an effective way to treat hyperpigmentation."

And, if you shave your armpits, glycolic acid could also be helpful for preventing ingrown hairs. “It’s great at smoothing out the skin, because of its exfoliation properties, and improving the area's texture,” she adds.

How to Use Glycolic Acid on Your Armpits

Since the underarms are a delicate, high-friction area of your body, it’s essential to go in with a proper game plan to avoid irritation. Many people on social media spotlight The Ordinary Glycolic Acid 7 Percent Toning Solution as their go-to underarm treatment — you just soak a cotton pad and swipe it over the area — “but any facial product with less than 10% glycolic acid should be fine in terms of the irritation factor,” says LoGerfo.

If you're worried about sensitivity, you've still got options. “You can find lotions or creams that have other ingredients that complement glycolic acid, like ceramides and aloe vera to calm and soothe the area," Dr. Viera says. "Use it at night on clean, dry skin before bed to minimize friction."

Who Should Try It

Though glycolic acid is known to be sensitive-skin friendly, “it’s not to say that it could never irritate,” says LoGerfo. The key is not to use it every day, avoid high concentrations, and avoid using it with other active, irritation-prone ingredients. Otherwise, “glycolic acid on your underarms can cause dryness, erythema, irritation, and inflammation — especially if it's used too often or in combination with other irritant ingredients such as retinol," says Dr. Viera. In fact, irritating the area could actually make skin darker.

And, if you have super-sensitive skin prone to irritation, instead of playing a guessing game with AHA percentages of your facial products, opt for one specifically formulated and tested for your underarms, such as Kosas Chemistry AHA Serum Deodorant.