Glycolic acid is lauded as an effective facial exfoliator and for use on ‘backne’. But is it safe to use the powerful alpha-hydroxy acid (AHA) on the scalp and on the delicate underarms?
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When it comes to beauty hacks, TikTok walks the gamut of the good, the bad and the plain questionable. So with beauty enthusiasts now deploying glycolic acid toner as a scalp scrub and a replacement for deodorant, where do these new uses sit on the spectrum? And all importantly, are they safe?
What is glycolic acid and how does it work?
First a quick science lesson on glycolic acid, which is derived from sugar cane and, like other AHAs, is classed as a chemical exfoliator. “Glycolic acid works in the uppermost layer of skin where it loosens dead skin, and dissolves the ‘glue’ that holds cells together for a gentle peeling effect,” Paulina Björkquist, customer developer and educator at Elixir Cosmeceuticals in Sweden, explained in our deep dive about glycolic acid. The brand's Glyactil Pads 10% are a best seller.
By casting off dead surface cells, glycolic acid triggers a chain reaction that reveals fresh new cells and an unrivalled glow. “Higher concentrations have a clarifying and brightening effect on sun-damaged skin while prolonged use affects the deeper skin layers and increases the production of collagen and elastin,” Björkquist added.
Can glycolic acid replace deodorant?
Not since #lubeprimer, which had over 7.1 million views on the video platform and saw creators advocate using Durex lube as primer, has a product swap generated so many hits. But, as of this writing, the hashtag #glycolicacidasdeodorant has racked up an enormous 1.3 million views with The Ordinary's Glycolic Acid 7% Toning Solution by far the most popular product for the job.
The premise is this: adding glycolic acid toner to a cotton pad and swiping it on your underarms claims to be an alternative to traditional deodorant by stopping sweating and body odour. But is there any solid science underpinning glycolic acid’s use as a deodorant?
So far, no. Any benefits are anecdotal and there are no peer-reviewed studies to corroborate TikTok's claims. More extensive research would also need to be done to establish whether glycolic acid temporarily lowers the pH of skin, making it more difficult for odor-causing bacteria to multiply.
Moreover, glycolic acid is made up of tiny molecules, meaning it is more powerful than other AHAs, so can cause mild stinging. This is one reason Björkquist recommended proceeding with caution if you have sensitive skin and not being overzealous when applying glycolic acid to the face. Given the skin on the armpit can be sensitive after shaving and is predisposed to friction from rubbing up against clothes, it's not a giant leap to see that it could be pretty painful to apply glycolic acid here every day in place of deodorant.
Photo: Getty
Glycolic acid for the scalp
While exfoliating scalp scrubs are a relatively new product category in Europe, K-beauty has been advocating the use of glycolic acid on the scalp for some time now. Converts swear by parting the hair and covering the scalp with the same glycolic acid toner they use on their face immediately before a wash. Massaged in for 10 minutes, one to two times a week, it’s said to remove product build-up and dead cells.
At first glance using acid on the scalp makes sense: it is skin, after all. And scalp scrubs are often laced with the chemical exfoliant salicylic acid to dissolve the glue-like bonds between dandruff and dry flakes on the surface of the scalp.
But there's a catch: the reason traditional skincare can’t be used on the scalp is because the skin there is sensitive in different ways. “The scalp is a special type of skin,” says scientist Augustinus Bader whose The Scalp Treatment supports cell function for a healthy scalp and stronger hair growth. “Compared to facial skin, the skin on the scalp is thicker, more vascularised with blood vessels and has more oil-producing glands than the skin on your face or elsewhere on the body. It also has a lower barrier function, meaning it's not as proficient at replenishing hydration as the skin on the face and body.”
In other words, the scalp has a different set of needs to the face – which is why The Inkey List Glycolic Acid Exfoliating Scalp Scrub , which is specifically designed for the scalp, also includes replenishing ingredients, such as algae, to balance out the seven per cent glycolic acid.
