I Tried TikTok’s Glycolic Acid Hack On My Dandruff & Wow

Dandruff and I go way back. There are probably a handful of things that have caused my flaky scalp over the years, like fluctuating hormones, all of the products I try as a beauty editor, or because I don't listen to trichologists when they tell me to wash my hair more often (I don't have the patience).

While my scalp has more good days than bad, it doesn't take too kindly to sweaty summer weather. Cue: more oil (and therefore flakes) than usual. I know I'm not the only one, though, as Google searches for 'why is my scalp so flaky?' and 'dry flaky scalp treatment' have increased by 120 and 50 percent respectively in the last week.

I swear by the Head & Shoulders DERMAXPRO Shampoo, £6, when it comes to eradicating loose skin in one full swoop. But if TikTok is anything to go by, we're beginning to see our scalps as an extension of the skin on our faces – and treating them accordingly. Not long ago, TikTok influencers went viral for using micellar water (yes, the stuff that you take your makeup off with) before shampoo, claiming that it eradicates oil, dry skin and dandruff flakes. It didn't quite work for me, but I couldn't resist another TikTok hack doing the rounds: drenching the scalp in glycolic acid toner – specifically The Ordinary's Glycolic Acid 7% Toning Solution, £8.

Though the hack isn't entirely brand new (The Ordinary's founder Nicola Kilner has been extolling its virtues for a while) it's getting a second wind this summer thanks to the scorching weather making scalps drier, oilier and subsequently flakier.

"If your scalp is oily, itchy or has dandruff, try this," TikToker @annaytime captioned a video with over 300K views. "I really like using this glycolic acid because the nozzle head tip makes it easier to apply to your scalp," she continued. "I like using a rat tail comb to section my hair. I use shampoo and conditioner after this and my scalp is refreshed and revived with no flakes."

TikToker @calistatee also went viral for using The Ordinary's glycolic acid on her scalp. After applying the solution bi-weekly and letting it work its magic for 30 minutes, she says her hair is now flake-free. "Exfoliating and moisturizing is key to this process #dandruffsolution," she captioned the video, which has 3.2 million views.

Derived from sugar cane, glycolic acid is an alpha hydroxy acid (or AHA) which chemically exfoliates the skin. It chips away at the bonds between skin cells to reveal fresher, smoother ones underneath.

The Ordinary's glycolic acid toner is interesting. It boasts 7 percent glycolic acid, which is pretty intense for a facial product. As a result, those with skin sensitivities have been enlisting it elsewhere, for example on cracked feet (it works, I'm proof) and now on the scalp.

When I met with top London scalp doctor Hannah Gaboardi recently, I put the hack to her. While she said it probably wouldn't promote hair growth, it will work to dislodge flaky skin and cleanse the scalp better when used as a pre-shampoo treatment.

Dr Usman Qureshi, aesthetic doctor and founder of Luxe Skin by Dr Q, agrees. "Glycolic acid based scalp exfoliators are so effective because of glycolic acid's small molecule size," he says. "Once applied to the scalp, glycolic acid works to shift dead skin cells from the skin's surface by breaking down and lifting the substance that causes dead cells to cluster together. It also lifts away excess sebum and product buildup." The result, says Dr Qureshi, is a cleansed, fresh scalp.

So I had to try it.

Thirty minutes before washing my hair, I drenched my scalp in the glycolic acid solution, taking care not to get any in my eyes (it runs!). The precise nozzle actually made it quite easy to concentrate the product to my scalp and roots, and I gave it an extra boost by massaging it in for a couple of minutes.

I lost track of time and ended up leaving the product on my scalp for over an hour. Considering the facial toner is a leave-on treatment, I wasn't worried about letting it do its thing for a little while longer than TikTok's beauty enthusiasts suggested. I won't lie, though: my hair felt crispy.

In the shower, I gave my hair two washes like normal using the Kérastase Bain Chroma Respect Shampoo, £22.40, and I followed with a heavy helping of the JVN Hair Nurture Hydrating Conditioner, £16, making sure I rinsed this out properly. According to Hannah, leaving product residue on the scalp could irritate it, making it itchy and potentially resulting in more flakes. A top tip I learned from hairstylist Adam Reed: once you think you're done rinsing, rinse for an additional two minutes.

The next day, my scalp was flake-free. Sure, it's a result, but my flakes tend to disappear after a double cleanse, anyway. I noticed even better results after practising the hack once a week for two weeks. Usually, my scalp would be very snowy a couple of days after a hair wash, but I noticed barely any loose, flaky skin in the days that followed. I worried that the acid might dry out my already fragile, dyed lengths. It didn't, and neither did it strip my brunette colour.

"Glycolic acid will benefit all skin and scalp types," confirms Dr Qureshi. "This is because it helps increase cell turnover." He explains its results will be best observed in people who are in their mid to late twenties. "This is when the cell turnover process starts to naturally decrease – even for scalps."

Dr Qureshi adds that glycolic acid can even help boost hydration in the skin on the scalp. There might also be a benefit to using glycolic acid on your actual hair strands. Deciem's science communications associate manager, Rita J Silva, explained that glycolic acid has the ability to soften hair fibres, temporarily reducing stiffness. It doesn't evaporate as quickly as something like water, so the hair softening benefits last longer.

Glycolic acid is a powerful exfoliating ingredient, and overusing it could cause irritation, including dryness and sore skin. This may make a flaky scalp worse. "I would advise using glycolic acid as a quick, rinse off treatment," says Dr Qureshi. "Glycolic acid is very powerful and you should be using it maximum once a week to get effective results without irritating the scalp."

There's no reason why you couldn't continue to use a glycolic acid facial toner on your scalp. But if you'd prefer a dedicated hair product, you might like The Inkey List's Glycolic Acid Exfoliating Scalp Scrub, £12.99. Applied pre-shampoo, the glycolic acid and gritty exfoliating particles slough away product buildup, grease and dead skin cells, which present as flakes. The brand recommends using the scrub once or twice a week.

If you're not keen on using acids and would rather stick to a physical scrub to dislodge buildup and dead skin, Hannah recommends the OUAI Scalp & Body Scrub, £32. "If you have a lot of sebum [oil] buildup, a scalp scrub is a great option every two weeks or once a month," she told R29 recently. "It'll take that dead skin off and encourage your hair to grow, because if the follicles are blocked, they can't grow."

Lastly, if you'd like to keep things simple, opt for a shampoo which reduces flakes. Try the Philip Kingsley Flaky/Itchy Scalp Anti-Dandruff Shampoo, £12.50. The star ingredients are lauryl betaine, which cleanses deeply, and piroctone olamine, which is antibacterial and helps minimise flakes and itching. I also like using the Head & Shoulders Classic Clean Anti Dandruff Shampoo, £5, sparingly, when my flakes are quite noticeable.