- Glycolic acid is a well-known alpha-hydroxy acid that is derived from sugarcane and used in a wide range of skin care products
- This acid is a type of chemical exfoliant that accelerates skin cell turnover, increases collagen production and boosts moisture retention
- Glycolic acid can address several skin conditions and cosmetic concerns, including signs of aging, acne, hyperpigmentation and ingrown hair
Glycolic acid is a member of the alpha-hydroxy acid (AHA) family. It is the smallest of this class, and is of low-molecular weight, which enables it to better penetrate the skin. Glycolic acid benefits are numerous and include deep exfoliation, skin brightening, increased moisture retention and skin cell turnover.
This acid is available in a range of skin care products such as cleansers, toners, moisturizers, serums and gels. These products have been proven to help treat a range of skin conditions such as acne, hyperpigmentation and signs of aging.
How glycolic acid works
Glycolic acid offers several skin revitalizing benefits. As a keratolytic, it can effectively penetrate the surface layer of skin to gently dissolve the bonds that hold dead skin cells together, enabling them to slough off. This exfoliative action reveals skin that is more youthful, smooth and fresh.
Exfoliation accelerates skin cell turnover which promotes collagen production, an important component of thick, healthy skin. This action results in diminished lines and wrinkles, and fades or eliminates the appearance of dark spots and hyperpigmentation.
As a humectant, glycolic acid draws and retains moisture within the skin to maintain hydration which effectively strengthens the skin barrier and skin health.
Glycolic acid has been proven to significantly improve both inflammatory acne (which manifests as papules, pustules, nodules and cysts) and noninflammatory acne (blackheads and whiteheads) when used as a peel.
Inflammatory acne lesions can be effectively treated and prevented due to the antibacterial benefits provided by this acid. It can kill Cutibacterium acnes (formerly Propionibacterium acnes) a known precursor to acne development.
Glycolic acid provides even greater benefits for noninflammatory acne. Due to its ability to reach deep within pores, it can dissolve the buildup of oil, dead skin cells and debris that cause blackheads and whiteheads to form. This characteristic acts as both a treatment and preventative.
While established acne medications are very effective in acne therapy, they do have one drawback, and that is to cause overly dry skin. Glycolic acid can counteract this side effect due to its ability to attract and maintain moisture; this also prevents skin from overreacting to this dryness and producing excess oil which can trigger acne breakouts.
In general, glycolic acid is safe for acne-prone skin. To avoid irritating or overdrying your skin, do not combine glycolic acid with retinol or benzoyl peroxide. Additionally, vitamin C can alter skin’s pH balance and should also be avoided; doing so could result in red, flaky, stinging and burning skin.
Collagen plays an important role in skin health by being a structural support and essentially being the scaffold that provides smoothness, elasticity and strength to skin. With age, this collagen production declines, and skin weakens and appears lax.
As an anti-aging treatment, glycolic acid can boost collagen stores and increase hydration to stave off fine lines and wrinkles. For mature skin, it has been shown to effectively treat photodamage by increasing levels of collagen and hyaluronic acid in the skin.
Aging skin typically develops dark spots, age spots and uneven tone due to damaging UVA and UVB rays. Glycolic acid is very effective in fading this hyperpigmentation and can be safely combined with other treatments for more dramatic results.
Glycolic acid revitalizes skin by targeting sun damage, reducing the appearance of lines and wrinkles, accelerating collagen production and moisture retention to support the skin’s matrix.
Ingrown hair can occur when hair follicles become clogged with dead skin, oil and debris. This prevents hair from growing outward and instead forces it to grow sideways under the skin.
Due to glycolic acids’ considerable exfoliative and keratolytic characteristics, with regular use, pores will remain open and this skin condition can be avoided. It can also be used to treat existing ingrown hair by softening the bonds of dead skin cells and exfoliating debris buildup.
For ingrown hair that results from hair removal practices such as waxing, shaving and plucking, glycolic acid will not be effective, as the cause is due to the sharp end of the hair shaft curling inward and penetrating the skin.
Keratosis pilaris treatment
Keratosis pilaris is a relatively common skin condition that is a result of a buildup of keratin, a protein that protects the skin from infection. Keratin plugs block hair follicles and cause patches of small, red or skin-colored bumps on the arms and legs.
Glycolic acid can effectively treat keratosis pilaris by softening and exfoliating these plugs, and promoting skin cell turnover. Skin will appear smoother and more evenly toned.
In one study, it was found a high concentration of glycolic acid significantly improved skin texture as well as hyperpigmentation of follicles in patients with keratosis pilaris.
You may also combine this acid with a salicylic acid product, as it also works as a peeling agent.
As both products can cause dryness, ensure you use a rich moisturizer after your treatment.
Glycolic acid works double duty by treating both hypertrophic (raised) and atrophic (depressed) scars.
For depressed scars (the most common type associated with inflammatory acne), when used in strengths of 70% as a peel, the acid removes the outer layers of damaged skin resulting in a more smooth, uniform surface. It’s collagen-building properties have been shown to have a modest affect in reducing the depth of these types of scars.
Raised scars can be diminished in appearance due to glycolic acid’s keratolytic quality. When used in low concentrations with retinoic acid, one study demonstrated a significant improvement in 91% of the patients.
Glycolic acid’s efficacy is based on the concentration and frequency of use, but another important consideration is combination therapy, as adding another topical or professional treatment can yield greater results.
Glycolic Acid Products
Depending on your goals, you may choose from multiple other-the-counter (OTC) skin care products or choose to undergo professional treatments for more dramatic results.
Typically, OTC options are available in concentrations of up to 10%; professional treatments up to 70%. To avoid irritating and overdrying your skin, include only one glycolic acid product in your skin care regimen.
For best results, opt for a product that is specifically designed for your skin type; many also contain additional active ingredients for additional benefits.
- Glycolic acid cleansers are available in varying strengths; those with low concentrations can be used daily; higher-strength should be reserved for once or twice a week. Oily skin will be more tolerant to its exfoliative effects but dry or sensitive skin can become irritated if used more than once or twice a week. These cleansers exfoliate dead skin cells and debris, reduce the appearance of lesions and maintain moisture levels.
- Toners are applied directly to the face after washing to balance the skin and remove any residue left over from cleansing; this also enables better penetration of other skin care products in your regimen. Toners are available in a number of strengths to target specific skin complaints—from 2%–30%—to gently exfoliate, fade hyperpigmentation and reduce oiliness.
- Creams and gels offer powerful moisturizing benefits due to their moisture-retention ability. They can be used daily to draw moisture to the skin, reduce the appearance of lines and wrinkles, and plump the skin.
- At-home masks are a deep treatment that can gently exfoliate dead skin cells, smooth the appearance of lines and wrinkles, and brighten the complexion. There are a variety of formulations with added ingredients such as salicylic acid for additional benefits. As these typically contain up to 30% glycolic acid, they should not be used more than once per week.
Light, medium and deep glycolic acid peels are administered in a professional setting, and are highly effective solutions to counteract signs of aging, hyperpigmentation and scarring. However, both medium and deep peels involve a lengthy recovery time.
If you are currently using an AHA or similar product within your skin care regimen, speak to your dermatologist before using glycolic acid, as the combination of exfoliative products may be too harsh for your skin.
Benefits vs. Side Effects
Glycolic acid has been shown to treat several skin conditions and to offer a number of benefits to rejuvenate and maintain skin health. That being said, this acid is associated with several mild side effects.
Although it’s considered safe for sensitive skin, some people do experience redness, irritation and discomfort. In some cases, dryness and skin flaking can also occur even when using a low-concentration product.
As with all AHAs, glycolic acid can make your skin more sensitive to ultraviolet light and cause photodamage while using the product. With this in mind, it is especially important to wear sunscreen with an SPF of 30 or more when outdoors.
Side effects will be greater with a professional peel, and the deeper the peel, the more pronounced the side effects. These include redness, dryness, irritation, burning, throbbing and swelling. More serious side effects can also occur such as scarring, infections and organ damage.
Who should avoid glycolic acid?
While safe for most people, glycolic acid is not suitable for people with:
- Rosacea, as glycolic acid can exacerbate redness and discomfort
- Dry skin, as it may be too harsh and cause increased irritation, dryness and flaking
- Acne, who are currently using other acne medications
Glycolic acid is a multitasking AHA that can successfully treat a number of skin conditions as well as address signs of aging. It is available in a wide range of OTC products in various strengths and at professional strength for light, medium and deep peels.
As a chemical exfoliant this acid stimulates skin cell turnover, and boosts collagen and moisture retention to strengthen skin. It not only exfoliates the surface layers of skin but penetrates deep within pores to break up and clear away plugs and debris.
Other benefits include skin brightening and toning, reduced hyperpigmentation, and softening of lines and wrinkles.
To avoid irritating and overdrying your skin, use just one glycolic acid product at a time.
- Kim SJ, Won YH. The effect of glycolic acid on cultured human skin fibroblasts: cell proliferative effect and increased collagen synthesis. J Dermatol. 1998 Feb;25(2):85-9. https://pubmed.ncbi.nlm.nih.gov/9563274/
- Green BA, Yu RJ, Van Scott EJ. Clinical and cosmeceutical uses of hydroxyacids. Clin Dermatol. 2009 Sep-Oct;27(5):495-501. doi:10.1016/j.clindermatol.2009.06.023
- Sarkar R, Ghunawat S, Garg VK. Comparative Study of 35% Glycolic Acid, 20% Salicylic-10% Mandelic Acid, and Phytic Acid Combination Peels in the Treatment of Active Acne and Postacne Pigmentation. J Cutan Aesthet Surg. 2019;12(3):158-163. doi:10.4103/JCAS.JCAS_135_18
- Valle-González ER, Jackman JA, Yoon BK, Mokrzecka N, Cho NJ. pH-Dependent Antibacterial Activity of Glycolic Acid: Implications for Anti-Acne Formulations. Sci Rep. 2020 May 4;10(1):7491. doi:10.1038/s41598-020-64545-9
- Reilly DM, Lozano J. Skin collagen through the lifestages: importance for skin health and beauty. Plast Aesthet Res 2021;8:2. http://dx.doi.org/10.20517/2347-9264.2020.153
- Bernstein EF, Lee J, Brown DB, Yu R, Van Scott E. Glycolic acid treatment increases type I collagen mRNA and hyaluronic acid content of human skin. Dermatol Surg. 2001 May;27(5):429-33. doi:10.1046/j.1524-4725.2001.00234.x
- Sharad J. Glycolic acid peel therapy – a current review. Clin Cosmet Investig Dermatol. 2013;6:281-288. Published 2013 Nov 11. doi:10.2147/CCID.S34029
- Pennycook KB, McCready TA. Keratosis Pilaris. 2021 Jul 26. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. https://pubmed.ncbi.nlm.nih.gov/31536314/
- Gozali MV, Zhou B. Effective treatments of atrophic acne scars. J Clin Aesthet Dermatol. 2015;8(5):33-40. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4445894/
- Kravvas G, Al-Niaimi F. A systematic review of treatments for acne scarring. Part 1: Non-energy-based techniques. Scars Burn Heal. 2017 Mar 30;3:2059513117695312. doi:10.1177/2059513117695312
- Chandrashekar BS, Ashwini KR, Vasanth V, Navale S. Retinoic acid and glycolic acid combination in the treatment of acne scars. Indian Dermatol Online J. 2015 Mar-Apr;6(2):84-8. doi:10.4103/2229-5178.153007
- Kaidbey K, Sutherland B, Bennett P, Wamer WG, Barton C, Dennis D, Kornhauser A. Topical glycolic acid enhances photodamage by ultraviolet light. Photodermatol Photoimmunol Photomed. 2003 Feb;19(1):21-7. doi:10.1034/j.1600-0781.2003.00013.x