an upclose photo of glycolic acid

What Is Glycolic Acid & How Is It Used?

Glycolic acid (GA) is a type of alpha-hydroxy acid (AHA) – a group of acids derived from naturally-occurring sugars.

GA’s small molecular size means it can penetrate deep into the skin and tackle various skin concerns, including blemishes, uneven skin tone and texture, and loss of firmness. Its many uses make glycolic acid truly the workhorse of AHAs.

This ingredient is available in various formulas, including chemical peels, serums, cleansers, and body creams.

In this guide from Nourishing Biologicals, we explain what makes GA so popular and how it can be used in your skincare routine for your healthiest complexion yet.

What Is Glycolic Acid?

Glycolic acid belongs to a group of acids known as alpha-hydroxy acids (AHAs). These are water-soluble acids made from naturally-occurring sugars, which also include lactic acid (sour milk), citric acid (citrus fruits), and mandelic acid (bitter almonds).

AHAs can be used to address any skin condition where there is a build-up of skin cells on the top layer of the skin. They work by dissolving the top layer of the skin – which is made up of dead skin cells – and revealing a fresh layer of skin.

AHAs are often applied in the form of superficial or medium-depth chemical peels but are also available as cleansers, serums, or creams.

Glycolic acid is derived from pure sugarcane. It has the smallest molecular size among all the AHAs, which can penetrate deeper and produce dramatic results. This makes glycolic acid the most widely-used AHA.

How Does Glycolic Acid Work?

Thanks to the wide variety of skin concerns that glycolic acid can address, it should be no surprise that glycolic acid has many different effects on the skin.

Glycolic acid helps peel the top layer of the skin and speed up skin cell turnover. It can increase the skin’s levels of hyaluronic acid, leading to increased hydration.

Studies show that glycolic acid can stimulate collagen production and improve skin elasticity. This happens because glycolic acid can penetrate deep into the skin and create change beyond superficial skin layers. Glycolic acid can go as deep as the dermis — the skin layer where collagen is produced.

Of course, how deeply glycolic acid can penetrate the skin depends on the concentration of the product (its percentage of glycolic acid) and how long it's left on the skin.

Concentrated chemical peels left on the skin for several minutes may be much more effective than cleansers that only make brief contact with the skin. As a result, higher concentrations of glycolic acid can lead to skin irritation and even cause skin damage, such as hyperpigmentation.

This makes it essential to start with more gentle glycolic acid products and increase their strength as your skin builds up a tolerance to GA.

How Do You Use Glycolic Acid?

Glycolic acid is commonly used as a superficial or medium-depth peel. Some skin peeling is expected and completely normal after a glycolic peel. However, GA peels may not cause significant peeling in most cases.

Instead, it works by targeting the deeper levels of the skin and improving the skin’s health and appearance. It is important to remember that it often takes several sessions before you start to see a difference within two weeks after your new skin develops.

Glycolic acid may also be available as a cleanser, toner, serum, cream, or body lotion. These products can be safely used twice daily. However, they may cause some irritation if you’re new to glycolic acid, which can be reduced by using products with low concentrations of the acids or alternating them with other skincare products.

Some dermatologists claim that glycolic acid can be used as a topical antioxidant, protecting the skin from damaging free radical molecules. However, studies also show that glycolic acid can make the skin more sensitive to ultraviolet (UV) light and potentially lead to increased skin damage. So, it is best to rinse off glycolic acid products before stepping out into the sun.

Which Skin Concerns Can Glycolic Acid Address?

Glycolic acid has a wide variety of applications in cosmetics. Here are some of the skin concerns that glycolic acid can address.


Since one of the leading causes of acne is dead skin cells clogging up pores, glycolic acid can help address the gunk that results in blackheads and zits and keep the skin clearer and healthier.

Glycolic acid can help manage acne by speeding up skin cell turnover, which means less build-up of dead skin cells. GA can also help smooth out poor skin texture caused by scarring and even a complexion marked by post-inflammatory hyperpigmentation.

In one study, participants were treated with glycolic acid peels every three weeks for a total of ten sessions. At the end of the treatment, most patients experienced a significant reduction in clogged pores, cysts, and pore size, while seeing an improvement in the brightness and smoothness of their complexions. The only side effect reported was a mild irritation.


Often called the “mask of pregnancy,” melasma is a condition that causes brown or blue-gray patches to form on the skin. While melasma can go away on its own, it usually takes months for the discoloration to resolve. Glycolic acid can be used to speed up this process.

Because it speeds up skin cell turnover, glycolic acid can help shed the discolored patches in the superficial layers of the skin. However, glycolic acid is more effective when combined with other ingredients.

For instance, research shows that glycolic acid works better when combined with hydroquinone than on its own.

Loss of Skin Firmness

Glycolic acid penetrates the deeper layers of the skin, helping to ramp up collagen production. This can help firm up skin that lost its firmness due to sun damage, smoking, aging, or rapid weight loss. Glycolic acid can even be used on certain body parts – like the arms – to help increase firmness.

Dry Skin

One of the more surprising uses of glycolic acid is to help increase skin hydration. It works as a humectant, which attracts water molecules to the skin. This means that when applied to the skin, glycolic acid can draw moisture from the air to your newly exfoliated skin, which hydrates the skin and prevents new fine lines and wrinkles.

Fine Lines and Wrinkles

Glycolic acid can reduce the look of fine lines and wrinkles through several mechanisms. In the first place, it exfoliates the top layers of the skin, which can flatten the skin’s surface and decrease the appearance of deeper wrinkles.

Glycolic acid can also speed up cell renewal and ramp up collagen production, which can help to fill in wrinkles. Last, glycolic acid increases skin hydration, which can help to “fill in” fine lines and wrinkles.

Research supports the anti-aging role of glycolic acid. For instance, one study found that glycolic acid was able to significantly reduce the actual depth and the total number of wrinkles. In addition, the study’s participants reported more satisfaction with the texture of their skin.

However, it’s important to note that glycolic acid won’t actually remove wrinkles. It can make them less pronounced, but it can’t completely get rid of them. In addition, the effects of glycolic acid are not permanent. For this reason, it’s important to continue using glycolic acid to help maintain results.

Who Shouldn’t Use Glycolic Acid?

Glycolic acid is associated with relatively few side effects. However, glycolic acid can increase skin sensitivity when exposed to the sun – leading to hyperpigmentation and collagen breakdown. For this reason, those that plan to be out in the sun should stop using glycolic acid products at least a week in advance.

It is also important not to use topical retinoids or products that rapidly exfoliate the skin when using glycolic acid.


Glycolic acid is a type of alpha-hydroxy acid (AHA) that can be used to speed up skin cell turnover, ramp up collagen production, and improve skin hydration. Because of its mild side effects, virtually anyone can use glycolic acid to address a wide variety of skin concerns.

However, it’s important to keep in mind that glycolic acid increases sun sensitivity. If you plan to be out in the sun, it’s best to avoid glycolic acid for at least a week.

At Nourishing Biologicals, we take pride in our products and our ingredients. We recommend sticking to skincare products that won’t increase your sensitivity to the sun. Say goodbye to toxic chemicals and say hello to products that have natural, harmless ingredients.


Glycolic Acid Adjusted to pH 4 Stimulates Collagen Production and Epidermal Renewal | Journal of Cosmetic Dermatology

Dual Effects of Alpha-Hydroxy Acids on the Skin | PMC

The Effect of Glycolic Acid on the Treatment of Acne in Asian Skin | NCBI

Efficacy and Safety of Superficial Chemical Peeling in Treatment of Active Acne Vulgaris | PMC

The Efficacy of Glycolic Acid for Treating Wrinkles: Analysis Using Newly Developed Facial Imaging Systems Equipped With Fluorescent Illumination | NIH

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