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What is glycolic acid and how can you use it in your skincare routine?

Last Updated: August 10, 2021

Glycolic acid: That mysterious ingredient that’s practically in every skincare product these days. But what exactly is glycolic acid, and, more importantly, what does it do to your skin?

We here at Grove caught up with our skincare expert and in-house formulation chemist Naomi Tennakoon to get to the bottom of this mystery ingredient. Plus, we’re exploring whether or not you should implement it into your skincare routine. Read on!

What is glycolic acid?

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Naomi Tennakoon: Glycolic acid is an AHA, which is an alpha hydroxy acid. And basically what it does is it very lightly exfoliates the skin chemically.

So there are physical exfoliants and there are chemical exfoliants. Physical exfoliants are like the scrubs where you feel the gritty particles (like a silica or walnut seed scrub), and they're literally using that particle to kind of rub against the skin to peel away the dead skin cells on top.

Then chemical exfoliants do the same thing, but chemically. So it's not a physical particle that's rubbing against the skin. It's chemical makeup gently sluffs away the dead skin cells on the top of the skin as you use the product.

So glycolic acid is one of these alpha hydroxy acids, but it's not the only chemical exfoliant. Others include lactic acid, malic acid, and citric acid, but those aren't typically used as much in products.

Since it’s the smallest particle size, glycolic acid is typically the most common AHA used in personal care products and is safe for many skin types.

What are some of the benefits of glycolic acid?

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NT: There are plenty of benefits from incorporating a chemical exfoliant like glycolic acid into your skincare routine.

It can brighten the skin because it’s, again, removing the dead skin cells. And so the newer skin is typically brighter and more healthy looking because it hasn't been exposed to the elements as much, giving you the appearance of better tone and texture.

It can also be good for reducing the appearance of fine lines. It’s not going to get rid of your wrinkles, and it’s not going to reverse signs of aging, but it can help with very tiny, surface-level lines.

Illustration of skin layers

And the last most common benefit is treating hyperpigmentation, or dark spots, because, again, exfoliating brings new skin to the surface. Overtime, scarring, including acne scars, can fade away, because you're exfoliating, and it's promoting the growth of new skin faster.

So, to reiterate, glycolic acid can:

  • Brighten skin.
  • Improve tone and texture.
  • Lessen the appearance of fine lines.
  • Help with hyperpigmentation.


Does glycolic acid treat acne?

NT: Glycolic acid is often used to treat acne because, through chemical exfoliation, it actually clears up some excess sebum (the oily substance produced by the sebaceous glands) and dirt that can get trapped in your clogged pores; therefore, it can kind of prevent acne from happening

It won't treat existing acne necessarily, but it will prevent new acne from forming.

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How do you use glycolic acid safely?

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NT: For people with sensitive skin, I recommend using a product with a low level of AHA. There's some brands that have very high levels of AHAs in their products, and it's super powerful, which is good.

But if you're a first time user, especially with sensitive and acne-prone skin, start with a low concentration around 1% or 2%. If that doesn't bother your skin, then you can increase the frequency of that low level.

So, if you use glycolic acid once, and then you don't experience any sensitization for a week, then you can use it once a week for about a month, before increasing use to two times a week.

But glycolic acid is the smallest AHA particle, which means it is the most powerful one, so it's important to be careful with how much you're putting on your skin, especially if you're a first time user.


AHA particle size: Is bigger better?

Glycolic acid is a smaller particle size, which means it can penetrate the skin slightly deeper. The larger the molecule for an AHA, the more mild of an exfoliant it will be.

But that is not necessarily a bad thing, because some people have very sensitive skin, and glycolic acid might actually be too much.

So starting off with a more mild AHA, or applying it once every other week, then once a week, and slowly increasing to at most two times a week is key.

Since glycolic acid, or any AHA, is an active ingredient, you do have to be careful to not stress your skin out too much.

How do you incorporate glycolic acid into your skincare routine?

NT: Moisturizing is key! When you exfoliate your skin using glycolic acid, your skin is “new,” and new skin is sensitive skin, so you want to make sure it's moisturized.

Having a good, basic moisturizer is a perfect companion to an AHA; and it doesn't need to be a super fancy moisturizer either.

Browse our list of the 7 best natural moisturizers if you’re looking for a new one!

You also don't want to mix too many actives (other chemical exfoliants, retinoids, serums, etc.) together. In general, when it comes to skincare, more is not always more.

Actives do interact with each other in different ways. And so I find that if you're going to use glycolic acid, or if you're going to use any AHAs, you want the rest of your skincare routine to be relatively simple. That way the AHA has the opportunity to do what it's supposed to do.

AHAs can also make your skin more sensitive to sunlight and more irritated from sunburns. So sunscreen should always be a part of anyone's routine. Always.

What’s the correct way to use glycolic acid?

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NT: Glycolic acid is often used as a mask. Sometimes there is a bit of concern that people will leave it on too long, so always look at the directions on the back of a bottle or package. And if it says 10 minutes, really only leave it on for 10 minutes before washing it off.

And don’t use a mask every day. Your skin needs time to balance itself out, and if you’re constantly exfoliating your skin you run the risk of hindering your skin rather than helping it.

But, depending on how it's being used, there are some skincare products with glycolic acid that are leave-on products, like a toner, serum, or moisturizer. These kinds of leave-on products are easy to incorporate into your regular skincare routine, and usually follow your cleansing or toning steps.

The difference between products like a mask or a toner is the concentration of glycolic acid. So a mask may use close to 10 percent, whereas a leave-on serum is only 1 or 2 percent.

What products have glycolic acid in them?

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NT: Glycolic acid is in a number of skincare products, but typically it’s in:

  • Masks
  • Cleansers
  • Toners
  • Serums
  • Moisturizers

What shouldn’t you use glycolic acid with?

NT: Don't use multiple products with glycolic acid at the same time since it might overwhelm the skin. I'm a believer in not overwhelming the skin with too many things, and I think the most important thing for your skin is to just have enough moisture.

Benzoyl peroxide, along with salicylic acid, is an active that’s used in acne treatments that doesn’t necessarily mesh with glycolic acid. It's not necessarily bad, but they can neutralize each other. When in doubt, contact an esthetician or dermatologist.

Over-exfoliating is also a concern, not just with chemical exfoliants, but physical as well. You never want to exfoliate your skin too much because your skin is a protective layer of your body, preventing infections and protecting you against the elements.

Also don't use glycolic acid products the same time you're using vitamin C products. If you are using vitamin c in your skincare routine, I would use it in the morning and the glycolic acid product at night.

If you are using a retinol, do not use glycolic acid at all since it could cause significant irritation and skin peeling if used together.

So, to recap, when using glycolic acid it’s best to avoid:

  1. Benzoyl peroxide
  2. Over exfoliating with physical exfoliants
  3. Vitamin C
  4. Retinols

Are there any side effects of glycolic acid?

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NT: While there are a ton of benefits of glycolic acid for brighter, plumper skin, as well as slowing the signs of aging, there is more of a concern for hyperpigmentation in melanin-rich skin.

If you have darker skin, hyperpigmentation can be triggered a lot more easily than in lighter skin tones. And so sometimes even glycolic acid, if someone uses too much and too often, can trigger a hyperpigmentation reaction.

Typically, then you would want to go into something like lactic acid, which is a larger particle size, and less “potent” in triggering hyperpigmentation.

Additionally, some people might experience skin irritation when first starting to use this ingredient. If this occurs, reduce the frequency of use or switch to a more mild AHA like lactic acid.

Glycolic acid vs. other skincare acids

Glycolic acid vs. salicylic acid

Both ingredients behave in a similar way but are suited for different purposes. Glycolic acid is good for evening skin tone and reducing hyperpigmentation, and is best suited for treating overall skin appearance.

If you are looking to treat acne specifically, salicylic acid is better because it removes excess sebum which is often a cause of acne — though this means that it can be drying for some people.

Glycolic acid vs. hyaluronic acid

Glycolic acid is a chemical exfoliator that removes dead skin cells from the top layer of your skin which leads to brighter, more even skin.

Hyaluronic acid is a humectant that draws moisture to your skin to keep it hydrated. These are great ingredients to use together in a routine.

Glycolic acid vs. lactic acid

Glycolic acid and lactic acid are both AHAs (alpha hydroxy acids) that work as chemical exfoliants for the skin.

Since lactic acid is a large molecule it does not penetrate the skin as deeply, and therefore is more mild, meaning it is better suited to sensitive skin.

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