Glycolic acid vs salicylic acid: what the experts say

The experts we track rate salicylic acid more highly, but the two do different jobs. Salicylic acid has a Guru Score above 90% and is the pick for oily skin, blackheads and whiteheads. Glycolic acid has a Guru Score of about 65% and is the one the experts reach for on rough texture and dark marks. The doubts about it are mostly about darker skin tones and stacking acids, so the real question is what you want to treat and how your skin reacts.

Below is how the two differ, how the experts in both our guides rated them, which they point to for each job, and what to know about irritation, sun and pregnancy.

What is the difference between glycolic acid and salicylic acid?

Both are exfoliating acids, but they work in different places. Glycolic acid is an alpha hydroxy acid, or AHA, the simplest of that family. It loosens the bonds between dead cells on the surface of the skin so they shed more easily, which leaves skin looking smoother and more even (Almeman, 2024; Kornhauser and colleagues).

Salicylic acid is usually called a BHA, or beta hydroxy acid. What sets it apart is that it is fat soluble, so it can follow oil down into the pore and concentrate there, which is why it is used so widely for acne (Arif, 2015). In the US it is an over-the-counter acne medicine at 0.5% to 2% (US acne rules).

Dr Dray, a dermatologist, notes the split: “Salicylic acid is great for blackheads and whiteheads.” And: “The glycolic acid can help with hyperpigmentation.”

Which do the experts rate higher, glycolic acid or salicylic acid?

Salicylic acid, clearly. It has a Guru Score above 90% from more than a dozen experts, with only one saying no. Glycolic acid has a Guru Score of about 65% from more than 10 experts, and a few of them said no or had doubts.

Seven experts appear in both our guides, and none of them rated glycolic acid higher. Four said yes to both: Dr Dray, Dr. Aanchal MD, Dr. Aleksandra Brown and The Budget Dermatologist, all dermatologists.

Two rated salicylic acid higher. Dr. Vanita Rattan, a doctor who specialises in skin of colour, said yes to salicylic acid and no to glycolic acid, and her reason is darker skin. Glycolic acid is a small molecule, and she explains what happens next: “In darker skin tones, this rapid penetration causes a shock response.” Her advice is “to switch to lactic acid or mandelic acid or even phytic acid.” Dr. Shereene Idriss, a dermatologist, said yes to salicylic acid and was mixed on glycolic acid. Her worry is stacking: she warns against using it on top of another chemical exfoliant: “do not double dip, otherwise you're going to be over-exfoliating your face and burning your face off in the process.”

Cassandra Bankson, a medical esthetician, said no to both, for the same reason. On an AHA and BHA peel she puts it: “AHAs are things like Glycolic Acid and BHA is salicylic acid, so you don't want to be using this and then use a salicylic acid cream or use a salicylic acid moisturizer and totally double up.”

Every verdict, with a link to the moment each expert gave it, is in our glycolic acid guide and salicylic acid guide.

Is glycolic acid or salicylic acid better for acne and oily skin?

Salicylic acid. The American Academy of Dermatology says it works best on whiteheads and blackheads, because it unclogs pores and exfoliates (AAD), and its 2024 acne guidelines give it a conditional recommendation (Reynolds and colleagues).

The experts we track point the same way. The Budget Dermatologist calls salicylic acid “my absolute number one go-to for topical acid when it comes to treating acne,” and adds: “This is far more effective than any other type of skincare acid.” Dr. Aleksandra Brown adds: “If you have oily skin and acne prone skin, using salicylic acid will help decrease the oiliness and help minimize the appearance of the size of the pores.”

As stronger peels done in a clinic, the gap is smaller. A review reports that in one split-face trial, 30% glycolic acid and 30% salicylic acid peels worked about as well as each other for acne, with salicylic acid lasting longer and causing fewer side effects (Almeman, 2024). Peels at that strength belong with a professional.

On the scalp the experts split. Dr Dray says that for flakes and dandruff “salicylic acid is so much better because it actually localizes in the sebaceous gland and really thrives in the oily rich environment of your scalp.” Others, among them The Budget Dermatologist and Dr. Shereene Idriss, use glycolic acid on the scalp too.

Is glycolic acid or salicylic acid better for dark marks and texture?

Glycolic acid. Dr. Aleksandra Brown puts it simply: “If your skin is either a combination or oily or you suffer from hyperpigmentation glycolic acid is going to be your jam.” Dr. Aanchal MD, a dermatologist, splits them the same way: “So if you have frank acne it's better to use a salicylic acid based spray. If you have dark spots then go for lactic acid or glycolic acid.”

The research is modest but real. In a 22 week trial in 74 women with sun-damaged skin, 76% of those using an 8% glycolic acid cream improved by at least one grade, against 40% on a plain cream, and the authors called it modestly useful (Stiller and colleagues). For dark marks left by spots, most of the evidence comes from professional peels: in two small trials in people with darker skin, adding a course of glycolic acid peels to a prescription cream helped more than the cream alone, clearly in one trial and as a trend in the other (Burns and colleagues; Sarkar and colleagues). Those were supervised peels, not everyday products.

A wash-off product is the easy way in. The Budget Dermatologist uses a 3.5% glycolic acid cleanser herself and says: “It's a generally low concentration of glycolic acid at only 3.5%, and it's only on your skin for like a minute before you rinse it off. So all skin types can use this.”

Which is gentler, glycolic acid or salicylic acid?

It depends on what you mean by gentle. On the sun, salicylic acid comes out ahead. In a small study, 3.5 weeks of 10% glycolic acid made skin more sensitive to UV light, with more redness, more DNA damage and more sunburn cells, while 2% salicylic acid did not (Kornhauser and colleagues, 2009). The US Food and Drug Administration (FDA) advises sunscreen while you use glycolic acid and for a week afterwards (FDA). Sunscreen is still a good idea with either.

On irritation, the experts do not all agree. Dr. Aanchal MD says that “BHA or Salicylic acid is less irritating.” Dr. Aleksandra Brown sees it the other way for leave-on products: she calls a 7% glycolic toner “middle of the road” and says “it's not super strong like salicylic acid leave on that's going to irritate more sensitive skin.” Dr. Vanita Rattan warns that “salicylic acid is a very drying product,” and US acne labels must warn that dryness and irritation are more likely if you use another acne medicine at the same time (US label rules).

Strength matters too. In the US, glycolic acid products for home use are judged safe at 10% or less with a pH of 3.5 or higher, as long as they protect against sun sensitivity or tell you to use sun protection (FDA), and over-the-counter salicylic acid acne products stop at 2% (US acne rules).

Whichever you use, think about timing. Dr. Aleksandra Brown explains that exfoliating acids “are best used at bedtime because your exfoliating acid is going to take off that top layer of the skin.”

Can you use glycolic acid and salicylic acid together?

Yes, but carefully. Plenty of cleansers, toners and peel pads combine the two, and several of the experts in both our guides have recommended products like that. The warning from Dr. Shereene Idriss and Cassandra Bankson above is about adding a separate leave-on acid on top of another by accident, which is the quick route to over-exfoliated, burning skin.

If you want both, a simple way is to pick one as your main exfoliant and keep the other in a wash-off product, or use them on different days, and let your skin settle before adding more.

Can you use glycolic acid or salicylic acid while pregnant?

Low strengths on the skin look reassuring, but the research is thin and our experts disagree. A review for family doctors says glycolic acid has not been studied in human pregnancy, but that using it on the skin should not be a concern because only a minimal amount is expected to reach the bloodstream (Bozzo and colleagues). A 2023 review of acne treatment in pregnancy says topical salicylic acid is considered safe because so little is absorbed, as long as it is not applied over large areas for long periods or under a covering, and notes the data are sparse (Ly and colleagues). Salicylic acid peels are a different matter, and a review of peels advises against them in pregnancy (Arif, 2015).

If you are pregnant, trying to be or breastfeeding, talk to your doctor or midwife before starting either one.