What is Glycolic Acid? Everything You Wanted to Know

February 10, 2026

By: Truly Beauty

Glycolic acid is an alpha hydroxy acid (AHA) that chemically exfoliates the skin to improve skin texture, fade hyperpigmentation, and combat keratosis pilaris. 

Due to its strength, glycolic acid must be used correctly to deliver results without compromising the skin barrier. The following guide explains how to use glycolic acid effectively to achieve visible improvement while protecting the skin barrier.

What is Glycolic Acid?

Glycolic acid is a chemical exfoliant that belongs to the alpha hydroxy acid (AHA) family. Derived from sugar cane, glycolic acid has the smallest molecular weight among all AHAs, which allows it to penetrate deeper into the skin for maximum benefits.

It's commonly used in skincare products like cleansers and serums as well as in professional treatments like skin peels to brighten skin tone, smooth texture, reduce acne, and fight signs of aging. 

Shop Truly's Best Glycolic Acid Products

Cloud Cream Pro-Peptide Facial Moisturizer

Plumping Gel Cream

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Smooth Legend After Shave Serum

Resurfacing KP Serum

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How Does Glycolic Acid Work? 

Alpha hydroxy acids like glycolic acid and lactic acid dissolve the bonds that hold cells together on the skin’s surface to remove dead skin cells, revealing smoother, brighter skin underneath.

It works differently to a physical exfoliant like a scrub. Instead of manually buffing away dead cells, glycolic acid (as with all AHAs), speeds up cell turnover by breaking down the substances that bind dead cells together.

Because glycolic acid is water-soluble, it primarily acts on the upper layers of the skin, where it helps improve fine lines, unclog blackheads, and reduce discoloration.

In addition to exfoliating the skin, glycolic acid increases collagen production, according to studies. Collagen is the protein responsible for keeping skin firm and plump. As we get older, the skin makes less collagen which can lead to visible signs of aging such as fine lines and sagging. Using glycolic acid regularly can help prevent the breakdown of collagen.

Benefits of Glycolic Acid for Skin

What can glycolic acid do for skin? Glycolic acid can address multiple skin concerns including signs of aging and discoloration. Here are some of the best glycolic acid benefits for skin.

1. Fades Hyperpigmentation

Glycolic acid is a great skincare ingredient for targeting hyperpigmentation like dark spots and age spots. Hyperpigmentation occurs when the surface of the skin becomes darker. Glycolic acid works by removing darker skin cells from the surface to reveal fresh, even skin.

It also helps fade the marks left behind by breakouts—also known as post-inflammatory hyperpigmentation. With every layer of skin it removes, scars and marks appear less visible. What’s more, glycolic acid can help fade sun-induced pigmentation, or brown spots.

2. Reduces Fine Lines and Wrinkles

Glycolic acid is a powerful anti-aging ingredient. It reduces the appearance of fine lines and wrinkles by accelerating skin cell renewal and boosting collagen production. By speeding up cell renewal, glycolic acid smooths the skin’s appearance, softening the look of fine lines and wrinkles. By increasing collagen production, glycolic acid plumps out wrinkles while firming and tightening the skin to reverse sagging.

Studies show that using a topical glycolic acid cream can actually thicken the skin to plump out lines. Patients that used a 15% glycolic acid cream for six months experienced a 27% increase in epidermal thickness.

Our favorite glycolic acid moisturizer for anti-aging is Truly's Cloud Cream Pro-Peptide Moisturizer which blends glycolic acid with hexapeptide to plump lines, visibly firm skin, and leave it immediately radiant. 

3. Combats Acne

Glycolic acid removes dead skin cells that block pores. Since clogged pores are a main contributor of breakouts, glycolic acid can help prevent pores from becoming congested and ultimately prevent acne breakouts. It’s especially good at warding off blackheads, whiteheads, and inflamed pimples.

Research shows that chemical exfoliation is a powerful method for addressing acne by clearing the buildup of pore-clogging dead cells, excess oil, and impurities.

While salicylic acid is one of the best ingredients for fighting acne as it penetrates deeper into the pores, glycolic acid works at a surface level to clean the pores and prevent blemishes. Plus, it can simultaneously target post-inflammatory hyperpigmentation—the marks left behind from acne. Dermatologists say it may even lessen the appearance of acne scars thanks to its resurfacing and collagen boosting effects.

4. Hydrates Skin

Interestingly, glycolic acid can also help to hydrate skin. As a humectant, it works to attract moisture, leaving the skin smooth, soft, and hydrated. Additionally, glycolic acid maintains your skin’s lipid levels, which also contributes to hydrated skin.

Lipids are healthy fatty acids that make up your skin barrier while sealing in hydration and keeping irritants out. They’re essential for healthy, hydrated skin. So with glycolic acid, you get the benefits of exfoliation without drying out your skin.

5. Combats Keratosis Pilaris

Keratosis pilaris (KP) is a skin condition that occurs when the hair follicles become blocked with a build up of keratin, a substance naturally found in the skin, nails, and hair. One of the best ways to manage KP is with a chemical exfoliant such as glycolic acid. Glycolic acid helps by removing the buildup and clearing the blockage to help soften bumps and alleviate dry skin.

Studies show that glycolic acid may be an effective treatment for managing keratosis pilaris thanks to its ability to clear plugs in the skin—and keep them clear by speeding up cellular turnover.

Our recommended glycolic acid serum for KP is Truly's Smooth Legend After Shave Serum which contains a blend of AHAs and squalane to clear plugs and visibly smooth rough, bumpy arms and legs.

6. Brightens Skin

As an exfoliant, glycolic acid sheds the accumulation of dead skin cells on the surface of the skin. Without that layer of dead cells, light can better reflect the skin, giving your skin a brightening boost. Best of all, you can expect to enjoy a natural glow from the very first use.

Underneath that layer of dead cells, fresh, smooth cells are ready to be revealed. By sloughing them away with a glycolic acid wash or toner, you can see a subtle glow straight after using it—even more so if you follow up with moisturizer.

7. Improves Penetration of Ingredients

While it’s not a direct skin benefit, glycolic acid allows deeper penetration of skincare ingredients, optimizing their effects. When your skincare products penetrate deeper, they work harder and ultimately give you faster results. By accelerating skin cell renewal, glycolic acid improves the penetration of active ingredients for enhanced results.

This is why dermatologists advise using glycolic acid as one of the first steps in your skincare routine. Whether it’s a glycolic acid face wash or toner, using it first allows the ingredients in your serums and creams to absorb better and work better.

8. Helps Reduce Body Odor

Glycolic acid is also known for its odor-fighting abilities. It targets body odor at the source by acidifying the skin, making it a less hospitable environment for odor-causing bacteria.

In recent years, using glycolic acid on the underarms has been a rising trend for keeping odors away. We've even developed a deodorant with AHA which effectively eliminates odor, replacing it with a fresh strawberry vanilla fragrance.

How to Use Glycolic Acid

Glycolic acid is a great at home treatment for a variety of skin concerns. Here are some tips for using glycolic acid and getting the most out of this chemical exfoliant.

1: Build Up Your Skin’s Tolerance

If you have sensitive skin, using glycolic acid too much or too often can cause skin irritation. Avoid this by increasing your skin’s tolerance to this active ingredient. Start by using a glycolic acid product just three times per week for the first week or two.

If your skin isn’t red, dry, or irritated, try using it four times per week for a couple of weeks. When you feel your skin has fully adjusted to glycolic acid, you can start using it daily.

2: Make it the First Step

Whether you’re using a glycolic acid toner or cleanser, make sure glycolic acid gets first place in your skincare routine. Because glycolic acid helps ingredients penetrate deeper, applying it first ensures you maximize the effects of the following products.

That being said, you’re better off applying glycolic acid in the evening as the first step of your routine because it can make skin more sensitive to UV rays if applied in the morning.

Of course, you should always be wearing sunscreen anyway. But if you plan on using a glycolic acid product in the am, be sure to slather on the SPF before leaving the house.

3: Pair With a Moisturizer

To minimize irritating effects of glycolic acid, apply a moisturizer after using. If you’re using a glycolic acid serum, apply it to cleansed skin before moisturizing with a lightweight cream.

Look for a moisturizer formulated with hydrating, soothing emollients and humectants like hyaluronic acid, aloe, and shea butter.

You can use the same trick for glycolic acid body products. Just apply the body lotion right after. Moisturizing after exfoliation is always a good idea as it helps support the skin barrier to prevent dryness and irritation.

4: Avoid Mixing it With Retinol

Retinol and glycolic acid are both highly potent ingredients that should not be used at the same time. You can use them both in the same skincare routine, just not together or mixed. This super strong combo can cause redness, flaking, and possibly even burning—especially if you already have sensitive skin.

Fortunately, glycolic acid works nicely with most ingredients, especially niacinamide, hyaluronic acid, and other hydrating ingredients like shea butter, and coconut oil. However, you may also want to avoid pairing it with vitamin C as this combo may also trigger irritation.

Side Effects of Glycolic Acid

Most people generally don’t experience side effects from using glycolic acid. However, those with dry or sensitive skin should stick to low percentage cleansers and serums to avoid flare ups. The worst glycolic acid side effects you can experience is due to using higher percentage glycolic acid products. Always stick to low percentage formulations. You can always go higher once your skin gets used to it.

If side effects from glycolic acid do occur, these most commonly include redness, burning, and flaking. If you experience any of these effects, reduce the frequency of use or stop using completely depending on the severity of the irritation.

People with darker skin should avoid overusing glycolic acid as it can lead to hyperpigmentation. This is because darker skin tones have a higher percentage of melanin in their skin and even minor irritations can trigger an inflammatory response, which can lead to discoloration.

You can always perform a patch test before using glycolic acid if you want to be on the safe side. But usually, side effects from applying glycolic acid are rare. You’re more likely to experience irritation from an in-office glycolic acid peel, as these contain a very high concentration of the active ingredient.

How Long Does it Take to See Results From Glycolic Acid?

Glycolic acid doesn’t mess around. In fact, many people notice brightening effects from the very first use. For most skin concerns, like acne and hyperpigmentation, it takes about a month to see an improvement. Within two months, you should see a significant improvement in the appearance of your skin.

As with all skincare ingredients, results vary from one person to another. Some may experience improvements within 4-5 weeks. For others, it could take several weeks to see a noticeable difference.

Is it OK to Use Glycolic Acid Everyday?

You can use glycolic acid products every day as long as they’re less than 10%. If you have sensitive skin, start by using glycolic acid 2-3 times per week. If your skin doesn’t react negatively, you can bump it up to 4-5 times per week, or even every day. Most importantly, always monitor how your skin behaves in response to applying glycolic acid skin care.

If your skin can tolerate daily use and you’re seeing positive results, continue with it. If you’re experiencing redness, dryness, or peeling, you’ll need to limit use or stop using it completely.

FAQ: Glycolic Acid

Is Glycolic Acid Safe for Sensitive Skin?

Glycolic acid is safe for sensitive skin when used in low concentrations and limited frequency. Always moisturize after application and perform a patch test before regular use.

How Long Does It Take to See Results From Glycolic Acid?

Many people notice brighter skin after the first use. For acne, hyperpigmentation, and texture, visible improvements typically appear within 4–6 weeks, with continued improvement over time.

Can Glycolic Acid Help With Acne Scars?

Yes. Glycolic acid improves the appearance of acne scars by increasing skin cell turnover and stimulating collagen production. It is most effective for surface-level scars and post-acne discoloration.

Can Glycolic Acid Be Used on the Body?

Yes. Glycolic acid is commonly used on the body to treat keratosis pilaris, ingrown hairs, body acne, rough texture, and discoloration, especially on the arms, legs, underarms, and bikini area.

Can You Use Glycolic Acid for Hair and Scalp?

Yes. Glycolic acid exfoliates the scalp, removes buildup, and unclogs hair follicles. This helps reduce flakes and supports a healthier scalp environment. Use scalp-specific formulas and avoid overuse to prevent dryness.

Can Glycolic Acid Fade Dark Spots?

Yes. Glycolic acid fades dark spots by removing pigmented surface cells and accelerating skin renewal. Consistent use paired with daily sunscreen delivers the best results.

What Should You Not Mix With Glycolic Acid?

Avoid using glycolic acid with retinol which increases the risk of irritation. Glycolic acid pairs well with vitamin C, hyaluronic acid, niacinamide, and ceramides.

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