Reviewed by Evan Lewis, PhD. Last updated August 2026.
Glycolic acid on feet works on the top layer of dead skin. A 7% toner swept over your heels a few nights a week thins the buildup that makes them rough. It does nothing under your toenails and nothing inside your shoes, which is where athlete's foot keeps coming back from.
The acid works on the top band. Everything in the lower half is a different job.
What is the glycolic acid foot hack?
Somebody took The Ordinary's Glycolic Acid 7% Toning Solution, a face product, and swept it over their heels with a cotton pad. Two or three nights a week, heels got smoother and feet smelled less. The clip went everywhere and the bottle sold out.
The hack is real. Our objection is not that it fails. It is that people then stop, because they think their feet are handled.
What does glycolic acid actually do to your skin?
It loosens the glue holding dead skin cells together so they shed. A 2025 review of topical keratolytics in Cureus describes the action as a reduction of corneocyte cohesion within the stratum corneum, facilitating desquamation, driven by proteolytic cleavage of keratin in corneocytes and corneodesmosomal junctions.
Think of a heel as a brick wall. Glycolic acid weakens the mortar, the bricks come away, the wall gets thinner.
The same review is blunt about where that ends up: structural and morphological thinning of the stratum corneum. That thinning is the whole point, and it is also the whole limit. Your outer dead layer gets thinner. Nothing below it changes, and nothing outside your skin changes at all.
The odor side follows from the same chemistry. Glycolic leaves the surface more acidic, and less buildup means less for skin bacteria to work on. If odor is your main complaint, our guide to what actually stops foot odor coming back covers the rest of it.
Does glycolic acid help athlete's foot?
Not in any direct way. Glycolic is a keratolytic, which means it dissolves keratin. It has no documented antifungal range, so shedding a layer of skin does not deal with the organism living in it.
It can make things feel better for a week or two, which is the confusing part. Scaly skin between the toes and along the sole is partly dead skin, so exfoliating it looks like progress. Then it comes back.
A 2023 review of tinea pedis in Drugs in Context puts the global prevalence at roughly 3% of the population with a lifetime risk of up to 70%, names Trichophyton rubrum and Trichophyton interdigitale as the usual organisms, and says most relapses come down to poor compliance. In other words, people stop early. A hack that feels like it worked is a very efficient way to make somebody stop early.
What about your shoes?
This is the gap that matters most, and it is the one nobody films. The same 2023 review reports that in one study, Trichophyton species was detected from the footwear of 47% of patients with tinea pedis, and lists indirect contact with contaminated belongings, shoes, socks and bedding, as a route of transmission. It also names occlusive footwear, warm and moist inside, as the thing that keeps the whole cycle going.
So you can exfoliate on Sunday night and put both feet back into the source on Monday morning. We flagged the same blind spot in the Lume on feet hack and in the whole-body deodorant version. Every one of these routines treats the foot as the whole problem.
Does it do anything for thick or yellow toenails?
No. A nail plate is a lid, and a 7% toner swept across the top of it is not getting under there.
How hard that lid is shows up in what it takes to soften it. A 2021 review in Dermatology and Therapy notes that urea at 40% to 50% can enhance nail permeability and soften the nail plate, and that medium to high concentrations improve the efficacy of topical antifungal drugs by increasing penetration. That is 40% to 50% urea to get through a nail. A 7% face toner is not in the same conversation.
Nails are also slow. New nail arrives at about 1.62mm a month in healthy young adults, so a whole toenail takes the better part of a year to replace itself. If your nails are the problem, start with what yellow, thick and brittle each point to, then read how to soften and trim a thick toenail safely.
How to use it on your feet without a bad week
- Clean, dry feet at night. Not straight out of a hot bath, and not on damp skin.
- One cotton pad, one sweep over heels and soles. Skip anything cracked open, and skip between the toes.
- Let it dry for two or three minutes, then moisturize.
- Two nights a week for the first fortnight. Three after that if your skin is fine with it.
- Stop for a week if you get stinging, redness or tight shiny skin. That is over-exfoliation, and pushing through it makes heels worse, not better.
- AHA products carry a sunburn alert. If your feet see daylight in sandals, keep that in mind on the days after you use it.
If you want a harder version of the same chemistry, a Baby Foot style peel runs the acid far higher in one sitting and sheds the whole outer layer over a week. Same effect, same two gaps.
What we do about the parts it skips
We make Sole Shield, so read this knowing that.
Here is the honest split. Glycolic will do more for rough heels than our spray will, because our spray is not an exfoliant and does not pretend to be. What it does is put iodine on the skin and into the lining of the shoe, every day, which is the half of the routine the hack has no answer for. It is 60ml, two ingredients, iodine and pure water. No alcohol, so no sting, and it does not stain skin or socks.
The research on iodine is about the mineral, not about our bottle. A 2024 scoping review in the Journal of Multidisciplinary Healthcare reports that within 1 to 5 minutes povidone iodine shows bactericidal, fungicidal and virucidal activity, and a 2020 review in Antimicrobial Agents and Chemotherapy puts that down to iodine oxidising key proteins, nucleotides and fatty acids inside the organism. Those are findings about an ingredient. We are telling you why we chose it, not what your feet will do.
The 200 plus foot care clinics that stock us tell us the same thing over and over. The people who come back are almost never the ones who skipped a step on their feet. They are the ones who never did anything to the shoes.
Sole Shield
For the two places a toner cannot go. Your shoes, and the skin between wash days.
Two ingredients: elemental iodine and pure water
60ml mist for feet and the inside of footwear
Water based, no alcohol sting, no staining on skin or socks
Stocked by 200+ foot care clinics across North America
Listed with Health Canada as a cosmetic
Shop Sole ShieldCommon questions
Does glycolic acid help athlete's foot?
Not directly. Glycolic acid is a keratolytic that sheds dead skin, and it has no documented antifungal range. It can make scaly skin look better for a week or two, which reads as progress. The organism itself is unaffected, and it is also sitting in your shoes.
Can you put The Ordinary glycolic toner on your feet?
Yes, and plenty of people do. It was formulated for faces, and foot skin is thicker, so most people tolerate it well. Sweep it over clean dry heels and soles two nights a week to start, keep it off open cracks and out of the toe webs, and moisturize once it dries.
Does glycolic acid help foot odor?
Usually a bit. It leaves the skin surface more acidic and clears the dead-skin buildup that skin bacteria feed on, so people often notice less smell inside two weeks. It only reaches your feet though, and the inside of a shoe is a bigger reservoir than most people expect.
Does glycolic acid work on toenail fungus?
No. The nail plate is a keratin barrier, and a 7% toner does not cross it. For comparison, urea has to be at 40% to 50% to soften a nail plate and improve how well topicals get through. Nails also grow at about 1.62mm a month, so nothing about a nail happens quickly.
How often should you use glycolic acid on your feet?
Two nights a week for the first two weeks, then three if your skin is comfortable. More is not better on feet. Stinging, redness or tight shiny skin means you have gone too far, and the fix is a week off, not a stronger bottle.
Why does athlete's foot keep coming back after it clears?
Two reasons, both in the 2023 Drugs in Context review. Most relapses come down to poor compliance, meaning people stop as soon as it looks better. And Trichophyton was detected in the footwear of 47% of patients in one study, so the shoes reseed the skin every morning.
The bottom line
Glycolic acid earns its place. Rough heels get smoother, feet smell better, and it costs about the price of a coffee a month.
Just be clear about what you bought. You bought an exfoliant for the top layer of your skin. Your nails and your shoes are still exactly as they were on Sunday.
Next: the daily foot routine active people stick to, and what a foot peel really does in the week after.
Evan Lewis, PhD, specializes in natural and nutritional therapies for the prevention and management of chronic diseases and their complications. His research spans chronic disease, diabetes complications, clinical nutrition, and nerve health, including the development of topical iodine therapy for foot care and wound health. IodinePure products are listed with Health Canada as cosmetics. The Ordinary and Baby Foot are trademarks of their respective owners, and product information here is from publicly available labeling. Sources: Dampa E. The Effectiveness of Topical Keratolytics (Alpha Hydroxy Acids, Beta Hydroxy Acids, Urea) in Treating Keratosis Pilaris. Cureus. 2025. Leung AKC, Barankin B, Lam JM, Leong KF, Hon KL. Tinea pedis: an updated review. Drugs in Context. 2023. Piquero-Casals J, Morgado-Carrasco D, Granger C, et al. Urea in dermatology. Dermatology and Therapy. 2021. Yaemsiri S, Hou N, Slining MM, He K. Growth rate of human fingernails and toenails in healthy American young adults. JEADV. 2010. Harun H, et al. Uncovering the benefits of povidone iodine in wound infection prevention and healing outcomes. Journal of Multidisciplinary Healthcare. 2024. Lepelletier D, Maillard JY, Pozzetto B, Simon A. Povidone iodine: properties, mechanisms of action, and role in infection control. Antimicrobial Agents and Chemotherapy. 2020.
