Of all the wild beauty hacks, I never thought I’d see the day we’re swiping acid on our armpits in lieu of deodorant. And yet, here we are – #glycolicacidasdeodorant has racked up millions of views, and curious folks (yours truly included) are dumping The Ordinary’s Glycolic Acid toner on cotton pads and saying sayonara to B.O. The claim? This classic skincare acid can kill underarm odor, lighten dark pits, and basically replace your deodorant. As someone who loves a good experiment (and hates 5pm pit funk), I had to try this trend, cautiously, mind you, because “chemical exfoliation” and “sensitive underarm skin” in the same sentence is… bold.

The Rationale: Why Acid in the Armpits?

Glycolic acid is an alpha-hydroxy acid (AHA) typically used on the face to exfoliate, fade dark spots, and smooth texture. It’s pretty powerful, it dissolves the “glue” between dead skin cells. The TikTokers figured: smelly armpits are caused by bacteria breaking down sweat, what if we use glycolic acid to slough off dead skin and lower the pH so bacteria can’t thrive? In theory, that could reduce odor.

Dermatologist Dr. Mona Gohara actually weighed in confirming that glycolic acid can help with odor: it lowers the skin’s pH and makes it inhospitable to the pong-producing bacteria. Essentially, you create an acidic environment where the usual underarm bacteria party can’t get started. I was surprised to learn this, but it makes sense – traditional deodorants often contain antibacterials or alcohol (also low pH) to similar effect.

However – big however – glycolic is not an antiperspirant. It won’t stop you from sweating. There’s zero aluminum in it (that’s the ingredient in antiperspirants that actually plugs sweat glands). So if you try this hack, know that you might smell okay for a bit, but you could still be rocking wet circles on a hot day. As a chronically sweaty person, I can confirm: during my trial, my pits were damp as usual, but the odor was noticeably less intense than without any deodorant. Science in action!

Another purported benefit: lightening dark underarms. Many people (especially with deeper skin tones or from shaving friction) have some underarm hyperpigmentation. Glycolic acid’s exfoliation can, over time, fade those dark patches by removing built-up dead skin and pigment. So the hack had a cosmetic appeal beyond just smell, kind of a two-in-one brightening deodorant. I noticed after a couple weeks my underarms did look a tad more even-toned, which for me was a welcome bonus.

My Experience: The Good, the Bad, the Tingly 😬

I swapped my usual deodorant for The Ordinary Glycolic Acid 7% Toning Solution (the MVP of TikTok hacks, apparently). Each morning after my shower, on completely clean skin (important – don’t do this on not-so-fresh pits), I’d soak a cotton pad and swipe it on like deodorant. The first thing I felt was a slight tingle. Not painful, but a “hello, I’m active” kind of feeling. If you’ve ever used glycolic on your face, you know the tingle is normal. On the armpits (which are more sensitive), it was a bit more intense, especially Day 1. I hadn’t shaved that morning – pro tip: do NOT apply glycolic right after shaving, unless you enjoy searing pain. Learned from others’ mistakes!

To my surprise, once it dried, my underarms felt… pretty normal. No sticky residue (looking at you, natural deodorants that never dry). Through the day, I did notice less odor than if I wear nothing. I did an exercise class and sniffed: not completely scent-free, but definitely milder than usual. Essentially, glycolic kept the dreaded B.O. at bay for maybe 6-8 hours. By evening, I wasn’t daisy-fresh, but it wasn’t a trash fire either.

Now the downsides. By Day 3, I started to get a bit of redness and sensitivity. Glycolic acid, after all, is a chemical exfoliant and the underarm skin is thin and delicate. I was using it every morning which in hindsight was overkill. Derms suggest maybe start with every other day or just a few times a week, especially if you’re using a 7-10% solution like The Ordinary. Overusing it can cause irritation, and ironically that can lead to more hyperpigmentation or even a compromised skin barrier. I noticed a couple of small bumps (like mild breakouts) which can happen if your skin gets too irritated or dry from acids.

I scaled back to using glycolic toner only after workouts (when I really wanted to freshen up) and not on freshly shaved days. This balanced things out. The redness subsided, and I still reaped the odor-control when needed. Importantly: I did continue to sweat like normal (so again, not a solution if pit stains are your arch-nemesis).

Another observation: one morning I skipped it and applied my usual aluminum-free deodorant, and it actually stung. That told me my skin was still a bit sensitized from the acid. It’s a good reminder that acid + broken skin (like micro-nicks from shaving) = OUCH. So I started shaving at night and doing glycolic in the morning, to give some buffer time. This helped a lot.

One more myth to bust

A lot of TikTokers are doing this hack in search of a “natural” deodorant alternative because they’re afraid of aluminum. The truth is, aluminum in deodorant isn’t the cancer-causing boogeyman the internet says it is – studies have not shown a clear link between aluminum antiperspirants and breast cancer or anything like that. The biggest downside of aluminum deodorants is they can sometimes cause irritation or allergic reaction in some people, and they do block sweat (which some prefer to avoid). So if you want to go aluminum-free, do it because it suits your skin/goals – not out of misplaced fear.

From my POV, glycolic acid is like a halfway point between regular deodorant and going commando. It’s not clogging sweat glands, and it can make you smell better than nothing, but it’s not as foolproof as a classic deo. On a light day, it might be enough. On a super active day in the sun? You might want to tag-team: perhaps use an AHA deodorant product at night to keep bacteria low, and a traditional (or aluminum-free) deodorant during the day for backup.

Safer Ways to Get Those Results

If the DIY approach feels dicey, you’ll be happy to know that brands caught on to this trend and there are now products specifically made to use AHAs on your underarms. These have the right percentages and often include soothing agents to offset irritation.

✨ Premium picks:

• Surface Deep Anti-Odorant AHA Pads – developed by a dermatologist, these pads are pre-soaked with glycolic acid plus calming aloe and glycerin. They’re basically the pro version of the hack and are so handy.

• Kosas Chemistry AHA Deodorant – an Instagram-famous serum deodorant with a blend of mandelic, lactic, and glycolic acids. It comes in a rollerball, feels like a lightweight gel, and helped my pits stay fresh with zero irritation (I’ve gone through two bottles).

💸 Budget-friendly:

• The Ordinary Glycolic 7% Solution – our star player, under $10, just use it wisely!

• Billie AHA Deodorant – yes, the razor brand makes a deodorant with lactic and glycolic acid that’s around $12.

• Native Acidified Deodorant – Native (known for natural deodorants) has a version with mandelic acid to fight odor in a gentler way. These options give you the odor-fighting benefits of glycolic without playing kitchen chemist, and they’re formulated to be kind to pit skin.

The Bottom Line

After a solid test drive, I’d call the glycolic deodorant hack “surprisingly effective – with a big asterisk.” It can work to reduce odor, yes. It can lightly exfoliate and brighten underarm skin over time. But it’s not a one-and-done replacement for a good deodorant/antiperspirant in all situations.

Would I recommend it? Cautiously, yes – for those curious, not overly sensitive, and willing to be patient and careful. And always remember, what works for one person’s pits might not for another. Body chemistry is weird and wonderful.

If you’re not sure what your skin can handle, or you want a more personalized approach (be it for acne, body odor, or any quirky skin issue), consider checking out an app like SkinAI. It won’t judge you for asking “Should I put acid in my armpits?”. Instead, it can analyze your skin and give tailored advice (and probably suggest patch testing first!). At the end of the day, the goal is to feel good and smell good in our skin, whether that’s via cutting-edge AI recommendations or a humble bottle of glycolic toner from The Ordinary. Stay fresh, friends – science and a little trial-and-error will lead the way.