Glycolic Acid in Skincare, Explained

Glycolic Acid in Skincare

By now, everyone, even the people who’ve been living under a rock, knows about glycolic acid in skincare. One way or another, it’s made its way into your skincare routine. And it’s because of the fact that it’s pretty much in everyone’s skincare routine, whether in the form of daily exfoliation or monthly peels, the superficial information about glycolic acid is not enough anymore.

When an ingredient is everywhere, recommended by dermatologists, and comes in several different products, you end up with more questions than you had in the beginning. We know it’s an exfoliant, but what makes it so popular? We know it helps with acne, but who’s stopping us from using it in much higher concentrations? Do you see what I mean? I talk a lot about it here too. So I’ve decided to put together a Q&A on glycolic acid. Keep reading to learn more about it and how to properly use it.

What Is Glycolic Acid?

Glycolic acid is a member of the alpha-hydroxy acids (AHAs) family. It’s actually the most popular of the bunch. Other members include lactic, malic, and mandelic acids.

Glycolic acid is water-soluble and it’s usually derived from sugar cane (1). Even though it was widely used in dermatological procedures like chemical peels, glycolic acid has since then made its way into daily skincare products.

Glycolic acid comes in the form of serums, toners, peel pads, cleansers, and creams. It’s a chemical exfoliant that prompts cell turnover, the speedy death of old cells, and the birth of new ones. And almost all of its benefits stem from this particular ability.

The reason why glycolic acid is the most popular alpha-hydroxy acid is that it has the smallest molecular weight (76.05) in that group (2). This makes it more penetrating than the other AHAs.

Glycolic Acid vs Other AHAs

Glycolic acid is different than other AHAs because your skin can absorb it better. And this is because glycolic acid has these tiny molecules that can slip through the cracks, so to speak, which isn’t easy for the other acids as they are bigger.

Imagine an automated store door at closing time. The door doesn’t move and it’s neither open nor closed. A cat would squeeze into a small place like that and successfully make it in. A chubby dog, on the other hand, would get stuck in the middle and bark at best.

Glycolic acid would be the cat in this scenario. And other acids would be the dog. The chubbier the dog, the less likely it is for it to make it inside. And if it isn’t clear, the door represents the outer layer of the skin.

How Does Glycolic Acid Work?

Glycolic acid targets the outer layer of your skin and weakens it, resulting in exfoliation and sloughing of dead skin cells (3). Imagine dropping some soap dish on your greasiest pan and watching the grease dissolve.

You should know that my analogies are barely on point. But that’s roughly how glycolic acid loosens the bond between dead skin cells and makes them shed off. This is how glycolic acid works on the skin. The good stuff happens as a result of this action.

What Are The Benefits of Glycolic Acid For The Skin?

Benefits and Side Effects of Glycolic Acid

There is quite a number of benefits of glycolic acid for your skin (4). Broadly speaking, it’s both anti-aging and anti-acne and helps all that’s related to these two concerns.

Glycolic acid stimulates skin turnover. As a result, it smooths out the skin texture, and eliminates rough, flaky skin. It also stimulates collagen production.

So it helps soften the look of fine lines and wrinkles on the skin. It’s great for photo-damaged skin as it also fades the look of hyperpigmentation.

And because of exfoliation, glycolic acid is one of the most popular ingredients to clear clogged pores and blackheads. Moreover, glycolic acid increases your skin’s hyaluronic acid production and epidermal thickness, resulting in smoother, healthier, and plumper skin.

So from the looks of it, glycolic acid seems like the do-it-all ingredient. In a way, it is. But it’s useless, and can even be counterproductive, when you don’t know how and when to use it or if you should use it. More on this in a bit.

What Are The Side Effects?

The side effects of glycolic acid, when used in skincare, can be lumped into two categories: using it when you shouldn’t be using it and overusing it.

First of all, the most common side effect of glycolic acid is irritation. By default, it’s a potential irritant and it’s all because of its penetrating abilities. Though some level of stinging and tingling is normal with any type of acid, irritation is another story.

Glycolic acid irritates compromised skin, can cause redness and burning, and increases your skin’s sensitivity to sunlight.

However, you can eliminate most of these side effects simply by using glycolic acid properly. To avoid sunburn, make sure you wear sunscreen daily.

On the other hand, there is such a thing as too much of a good thing. So even if your skin is normally fine with glycolic acid, using it too frequently carries the potential for all of these side effects (5).

Who Should Use Glycolic Acid?

In theory, you can use glycolic acid if you’re dealing with wrinkles, acne, hyperpigmentation, flakiness, and roughness. Anyone with normal, oily, and overall tolerant skin can use glycolic acid to address their issues.

However, you shouldn’t use glycolic acid if your skin is dry, or sensitive, or if you have a skin condition like rosacea.

How To Use Glycolic Acid in Your Skincare

You can only collect the benefits if you know how to properly use glycolic acid. Imagine jumping on the treadmill. You need to first walk at a slow pace to warm up. And then you pick up the pace in a gradual manner and then can even start running. The warm-up and the pace have a defining role in how long you’ll be able to go steadily and how beneficial the cardio will be.

Now imagine jumping on it and running without warm-up whatsoever. You’ll soon get cramps and will have to stop and take a break. It’ll take too long until the cramps are gone and you’ll probably give up on cardio. You need to follow the system: warm up, and pick up the pace progressively.

Similarly, slowly building up is the best way to incorporate glycolic acid into your skincare routine. Here’s the first rule of using glycolic acid: use only one glycolic acid product. It doesn’t matter if it’s a serum or a toner. Get one product and start with that.

Use it once a week at night for a whole month and see how your skin changes. More importantly, see if there’s any recently formed redness. It may be a sign of over-exfoliation and you might need to reduce the frequency.

Once your skin gets used to glycolic acid, you can increase the frequency and can even try higher concentrations.

How Often Should You Use Glycolic Acid?

Glycolic isn’t something like an acne medication. So there’s no need to use it every single day. I can’t imagine a scenario where your skin needs exfoliation every single day.

Having said that, there’s no rule out there for this. It’s an exfoliant. And generally, dermatologists recommend exfoliating 1-3 times a week. But you know your skin best. And as I said, there is such a thing as over-exfoliation.

How To Apply Glycolic Acid

Even though this depends on your product, make sure you apply your glycolic acid on clean, dry skin. If your skin is wet, it’ll be more absorbing. So glycolic acid can cause burning and a full-blown redness if you apply it when your skin is wet. It’ll be more irritating.

If it’s a toner, get a few drops on a cotton pad and wipe it evenly on dry skin, and wait for it to dry before moving on to other products. If it’s a serum, get a few drops and apply it after your toners and serums are fully absorbed.

If it’s a cream, apply it as the last step of your routine. Whatever product you’re using, sunscreen is vital. As glycolic acid can temporarily make your skin prone to sunburn, you should wear sunscreen. If you don’t, glycolic acid can cause hyperpigmentation.

If you apply it on dry skin and use it properly, glycolic acid feels a little tingly at first for about 10 seconds. You may also temporarily flush for a minute. Then the feeling goes away. This is expected. Anything else can be problematic.

Can Glycolic Acid Cause Purging?

If you readily deal with acne, glycolic acid can temporarily worsen acne aka purging. Even if you don’t really struggle with acne, you can experience breakouts at first or pustules or red bumps, which eventually disappear.

This is usually because glycolic acid increases skin turnover and it reveals underlying impurities. But it’s only to get rid of them. The only way to make sure it’s a temporary purging and not signs of over-exfoliation is to stick with the “start slowly” rule.

What Can’t You Mix With Glycolic Acid?

There are certain ingredients you should avoid mixing with glycolic acid. This is to avoid irritating your skin, which may require a long break from using actives in your routine.

Even if you have normal skin and a healthy skin barrier, slathering it with heavy actives will cause problems. As a general rule, don’t layer glycolic acid with other exfoliants like lactic acid or salicylic acid. And don’t use retinol or vitamin C in the same routine you use glycolic acid.

I have sensitive skin and I did a similar thing once. Well, I lived. So it’s not the end of the world. However, continually doing this will weaken your skin barrier and take you right back to square 1.

Remember that combining actives also means combining two separate potential irritants. So if you’re using glycolic acid and want to add in retinol to better target acne, you may experience a worse case of skin purging, which will make you cut things short without benefiting from either of the ingredients.

The best way to layer acids is to assign days of the week for each. Use a retinol product one day and use glycolic acid one day. Use your vitamin C serum during the day and your glycolic acid toner in the evening. Keep things separate to be safe.

On the other hand, ingredients that aren’t potential irritants can be layered with glycolic acid. Hyaluronic acid or other humectants that simply hydrate, or emollients that increase moisture can be used together with glycolic acid in the same routine.

Read Next: The Best Drugstore Glycolic Acid Products


  1. Moghimipour E. (2012). Hydroxy Acids, the Most Widely Used Anti-aging AgentsJundishapur journal of natural pharmaceutical products7(1), 9–10.
  2. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 757, Glycolic acid. Retrieved August 5, 2021 from
  3. Fartasch, M., Teal, J., & Menon, G. K. (1997). Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of the epidermal barrier. Archives of dermatological research289(7), 404–409.
  4. Kornhauser, A., Coelho, S. G., & Hearing, V. J. (2010). Applications of hydroxy acids: classification, mechanisms, and photoactivity. Clinical, cosmetic and investigational dermatology3, 135–142.
  5. Wang X. (1999). A theory for the mechanism of action of the alpha-hydroxy acids applied to the skin. Medical hypotheses53(5), 380–382.

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