Why People On TikTok Are Using Glycolic Acid As Deodorant

TikTok is full of beauty hacks; some genuinely smart (like the one-minute messy bun trick and the easy face-lifting technique), others decidedly questionable. This month, the app's beauty enthusiasts are ditching their deodorant in favour of a swipe of glycolic acid toner under their arms, claiming it stops sweat in its tracks, prevents body odour, and minimizes pigmentation. The hashtag #glycolicacidasdeodorant has racked up 1.3 million views as people catch on to the trend, with The Ordinary Glycolic Acid 7% Toning Solution emerging as the most popular product. But does it actually work — and more importantly, is it safe?

"Derived from sugarcane, glycolic acid is a chemical exfoliator, also referred to as an alpha-hydroxy acid or AHA," says Dr. Ana Mansouri, aesthetic doctor and skin expert at Kat & Co. "Its small molecular size makes it powerful and enables penetration deep into the skin layers. It essentially works by breaking the bonds between dead skin cells, which helps to resurface the top layer of the skin." Used over time, glycolic acid can help fade pigmentation and improve rough skin texture.

Glycolic acid is great on paper, but there are potential side effects and drawbacks you need to know about before using it. The ingredient is best used at night at relatively low percentages once or twice weekly, after cleansing and before moisturizer. As it can make skin sensitive to sunlight, wearing SPF during the day is all the more important. It pays to be careful with how often you're using it, too. "Overuse can lead to over-exfoliation, which can break the skin barrier function and lead to irritation, dehydration, and breakouts," says Dr. Mansouri.

Judging by the countless TikTok videos, beauty enthusiasts are using glycolic acid as deodorant mainly because they're looking for natural alternatives and love the idea of a multipurpose product. Dr. Priya Verma, medical director at Nova Aesthetic Clinic, explains that glycolic acid is said to "lower the pH of the underarm, creating an inhospitable environment for odour-causing bacteria," which explains why many TikTokers are championing it for reducing body odour. However, Dr. Mansouri says that this is simply a theory, and it isn't actually proven to reduce odour. What's more, Dr. Verma says there is little evidence that glycolic acid reduces sweating. "In fact, water from sweat will neutralize glycolic acid, reducing any benefits of the acid application," she says.

In other words, any benefits of that nature are based on anecdotal evidence. One thing glycolic acid may help improve is underarm pigmentation. (Of course, body pigmentation is entirely normal, but some people may wish to get rid of it as a matter of choice.) "As glycolic acid exfoliates the skin, it promotes a more rapid cell turnover and reduces the thickening of the skin that leads to underarm hyperpigmentation," explains Dr. Verma. "Used correctly, it is effective in reducing unwanted hyperpigmentation." Dr. Mansouri adds that there are better options for this purpose in the underarm area.

Glycolic acid can cause irritation on facial skin, so it follows that it can do the same to underarm skin. "Armpit skin is already sensitive in nature due to constant friction and rubbing, as well as a moist and occluded environment," says Dr. Mansouri, who adds that shaving can cause further sensitivity. That slight tingle you feel when applying glycolic acid toner to your face could be pretty painful on just-shaven underarms.

Dr. Verma adds that glycolic acid facial toners would be completely unsuitable for use if you’re having a course of laser hair removal in the underarm area. "Glycolic acid isn’t suitable for all, and more sensitive skin types may see an adverse reaction. Overuse can also lead to over-exfoliation, which compromises the skin’s protective barrier," causing redness and flakiness, she explains. "In the hot and humid environment of the underarm, this would be very undesirable."

While glycolic acid is said to reduce hyperpigmentation when used correctly, if you're using it too often and in high concentrations, it can actually worsen hyperpigmentation due to irritation. "I would prefer to keep the AHA use to the face, as this is what your product will have been formulated and intended for," says Dr. Mansouri.

I'm all about putting trends and hacks to the test, occasionally even when they're ill-advised, so I couldn't resist giving this a go. I decanted a little glycolic acid onto a cotton pad before swiping it underneath my arms. Even though I'd waited a couple of days after shaving to avoid the dreaded sting, my skin still tinged. The initial application felt a little sticky, and I can safely say it did nothing to prevent sweating throughout the day — in fact, that stickiness lasted all day, which put me in a bad mood. I decided to test its supposed odour-reducing properties by going on a long walk; unfortunately, it didn't hold up as well as I'd hoped. The smell wasn't as strong as I'd anticipated, but I still noticed it at the end of the day and I couldn't wait to jump in the shower.

I love using The Ordinary's glycolic acid toner on my face (it helps fade marks left behind by spots and smooths bumpy skin texture like no other) but I wouldn't recommend using glycolic acid under your arms — not when there are so many great deodorants out there. Dr. Mansouri seconds this. "I am not a fan of this trend at all and would definitely recommend sticking to tried and tested deodorants or antiperspirants with research behind their use," she says. "Skin care should be backed by science, not trends."

Plenty of TikTok videos warn that aluminum in deodorant is "unsafe" to health, but Dr. Mansouri busts this myth. "In contrast to popular belief, there is no hard evidence to suggest that aluminum chloride is actually harmful," she says. Dr. Verma also says to remember that aluminum-free "natural" deodorants won’t prevent sweating, but will simply combat odour.

Having tried hundreds of deodorants on the market, for me nothing beats Mitchum Powder Fresh Anti-Perspirant Roll On. It doesn't let a single bead of sweat pass, nixes odour, and really does last all day. The Shower Fresh version is just as excellent and is available in an aerosol version if you prefer quick-drying sprays. If you like natural deodorant, you might enjoy Scully's Deodormint Spritz. The formula is an astringent so it wipes out odour-causing bacteria and makes underarms feel fresher for longer.

Firstly, sweating is entirely natural, but Dr. Mansouri says that anyone who struggles with excessive sweating or odour should see a doctor or dermatologist, who will be able to prescribe treatments. "Botox is another temporary option for sweating, although costly and laborious," says Dr. Mansouri. "I’m a big fan of the miraDry treatment that actually reduces underarm sweat permanently — my patients end up not needing to even use deodorants after having had this."

The expert consensus is that glycolic acid should be reserved for use on the face rather than underarms. Sorry, TikTokers: This hack isn't worth the hype.