Glycolic Acid: Benefits, What It Does, & How It Works

Glycolic acid is seemingly everywhere these days – from social media and beauty halls, to French pharmacies and even supermarket shelves.
But, what does it do, and is it the right ingredient for your skin type? The amount of choice can be both tempting and overwhelming. So to avoid wasting money on the wrong product, let’s delve deeper into the science behind this chemical exfoliant, and help you make the right choice for your skin.

Understanding Glycolic Acid

What is Glycolic Acid?

Glycolic acid is probably the most famous of the alpha hydroxy acids (AHA), and a firm favourite among many dermatologists.
Its main use in skincare is to exfoliate the skin, improve skin texture and even out the skin tone. Found in plants like sugarcane, glycolic acid can also be made in a laboratory too. Glycolic acid is known for having exfoliating, brightening, smoothing and anti-ageing benefits for the skin. [1]
Glycolic acid has the smallest molecules out of all the AHAs – even smaller than mandelic acid or lactic acid. [2]

How does Glycolic Acid work?

AHAs like glycolic acid are a type of active skincare ingredient known as chemical exfoliants. This antioxidant works on the surface of the skin by gently breaking down the adhesions (bonds) between dead skin cells. [1]
When used correctly, AHAs encourage old, dead or dull-looking skin cells to be released from the skin surface (known as the stratum corneum), and removed, without disrupting or damaging the delicate skin barrier. This reveals the healthier, fresher-looking cells beneath.
In fact, you shouldn’t need to use any sort of rubbing action when applying AHA products. AHAs are water soluble, and unlike scrubs, they work without the need to scrub or buff at your skin. Unless the instructions say differently, you can usually leave it on and layer your usual moisturiser and – if applied in the morning – sunscreen on top.

Glycolic Acid Benefits

1. Gives Skin a Smoother, Fresher, More Radiant Glow

Glycolic acid gently “nudges” or encourages dead skin cells that collect on the surface of the skin to shed. This leads to an improvement in skin texture.
Glycolic acid can also enhance how smooth and even your skin looks. Like retinoids, it’s an effective treatment to help fade and prevent visible pigmentation, as well as signs of skin ageing like fine lines and wrinkles. Glycolic acid is also helpful for reducing breakouts and blemishes [3, 4]

2. Replaces Physical Scrubs

Physical scrubs or tools like facial brushes can agitate and irritate the skin, whereas glycolic acid is usually found in liquid skincare products like toners or serums. Our skin barrier is delicate, and scrubs can cause irritation, redness, inflammation or damage. Glycolic acid helps you achieve a more radiant complexion without needing to rub or scratch at the skin surface. [5]

3. Helps Fade Sun Damage & Dark Spots

Studies show that even applying glycolic acid in low concentrations can noticeably improve the appearance of uneven skin tone, including conditions like post-inflammatory hyperpigmentation (dark spots from old acne spots), rough texture, acne scarring, and dullness. [6]

It’s also common for people to use glycolic acid to treat sun spots (solar lentigos), which often appear as a result of sun damage. [7]

However, glycolic acid can make your skin more sensitive to the sun. You should avoid direct sun exposure, especially during the hottest or brightest times of the day (usually from around 11am – 4pm) and protect any exposed skin using a broad-spectrum sunscreen every day, and wear UV protective clothing and a wide brimmed hat. [8]

4. Prevents Clogged Pores

Dead, damaged cells that sit on top of the skin aren’t just what cause our skin to look dull, uneven or lacklustre. Dead skin can also find its way into pores, causing them to become clogged or enlarged. This is a key reason why spots, blackheads, whiteheads and acne form.
You can also find glycolic acid products that are designed to use on the body, and can help reduce rough bumps on the surface of the skin called keratosis pilaris (commonly known as “chicken skin”). [9]

5. Improves the look of Fine Lines & Wrinkles

Glycolic acid can also help smooth the appearance of wrinkles and fine lines, because it helps boost both collagen and hydration in the skin.

6. Stimulates Collagen in the Skin

lycolic acid stimulates fibroblasts – the cells responsible for producing collagen and elastin. Collagen is an essential structural protein found in our skin, nails and bones. Both collagen and elastin keep skin looking firm, elastic and youthful. However, by our mid-twenties, our skin starts to lose collagen and production slows down as we age.

Studies have shown that AHAs may boost collagen production in the dermis, which is the inner layer of the two main layers of skin. This helps with fine lines, wrinkles, and uneven skin texture. [10]

Boosts Skin Hydration

Glycolic acid is one of the most underrated skincare ingredients when it comes to keeping your skin hydrated. Yes, it is an exfoliating acid, but it’s also an effective option for dry skin – especially in colder or drier weather.
Not only does it remove the dead or damaged cells on the skin surface, it also helps your body create mucopolysaccharides, which then helps boost your skin’s ability to produce natural hyaluronic acid on its own. [11]
If you have dry skin, gentle exfoliation also allows active ingredients and moisturisers to penetrate the skin more deeply – rather than just sitting on the surface. This helps to improve overall hydration and reduce water loss from the skin (known as trans epidermal water loss or TEWL). [2]
A healthy, hydrated skin barrier is one of the easiest and most efficient ways our skin protects us from the environment, preventing skin damage, inflammation, early ageing or an infection.

How to use Glycolic Acid

In-Clinic Skin Treatments

Glycolic acid is a common ingredient used in chemical peels. A chemical peel is a treatment that must be performed by a dermatologist or licensed aesthetician, as it contains much higher concentrations of AHAs. [12]
This treatment is effective for all skin tones, including people with darker skin types and complexions. It can make a noticeable, positive difference to visible dark spots and hyperpigmentation, fine lines, acne and uneven skin texture – especially if these skin conditions are persistent, or you wish to see visible results more quickly. [13]
Make sure the dermatologist or aesthetician you choose has successful experience with patients who have a similar skin tone and condition to yours. Follow the aftercare instructions to make sure your skin heals properly.

In Your At-Home Skincare Routine

This popular ingredient is found in all kinds of at-home, topical skincare products (these are applied on top of the skin), from cleansers and toners, to serums and moisturisers.
You can add glycolic acid to any stage of your skincare routine. It is, however, a potent active ingredient. If you use it too often – or with too many other exfoliating ingredients – you could irritate or damage your skin barrier.
If you’re concerned, perform a patch test on a small area of skin first or ask a dermatology expert. Reach out to us from your dashboard if you’re a subscriber, or get advice from your dermatologist.

Is Glycolic Acid Right for You?

Glycolic acid suits normal, dry, combination and oily skin types best. Because it can penetrate deeper into the skin, it may cause irritation if you are already using strong active ingredients or if you have very sensitive skin. [2]

Always go slow. Introduce ingredients like retinoids, glycolic acid and Vitamin C, one by one. If your skin tolerates one strong active well, and you don’t experience any side effects, you can then try introducing a new one if needed.
Already using actives in your routine? Follow the correct advice for your skin type and condition – subscribers can do this from their dashboard. If you’re not a subscriber yet, we recommend asking a licensed dermatology expert for advice or reading our article on how to use glycolic acid and retinol together.
Slow progress towards long-term healthy skin is the win we’re aiming for. And you should always think of skincare as a marathon, not a sprint.

Products Mentioned

SPF50 Photodamage Defence Sunscreen
Vitamin C 15%: Fresh Batch Ascorbic Acid
Collagen Complex
Hydrating Hyaluronic Acid + Vit B5 Serum

References

Fartasch M, Teal J, Menon GK. Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of the epidermal barrier. Archives of Dermatological Research [Internet]. 1997 Jun 1;289(7):404–9. Available from: https://www.ncbi.nlm.nih.gov/pubmed/9248619
Tang SC, Yang JH. Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules : A Journal of Synthetic Chemistry and Natural Product Chemistry [Internet]. 2018 Apr 10;23(4). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6017965/
Narda M, Trullas C, Brown A, Piquero‐Casals J, Granger C, Fabbrocini G. Glycolic acid adjusted to pH 4 stimulates collagen production and epidermal renewal without affecting levels of proinflammatory TNF‐alpha in human skin explants. Journal of Cosmetic Dermatology. 2020 Jul 24;20(2):513–21.
Chen L, Lu L, Tu S, Zhang T, Du X, Chen L, et al. Efficacy and safety of 5% glycolic acid‐based Gel essence in the treatment of mild to moderate acne. Journal of Cosmetic Dermatology. 2022 Feb 19;21(10):4482–9.
Rodan K, Fields K, Majewski G, Falla T. Skincare Bootcamp: The Evolving Role of Skincare. Plastic and Reconstructive Surgery – Global Open [Internet]. 2016 Dec;4(12):e1152. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5172479/
1.Zhao J, Zhou B, Hou Y, Li L, Zhuo F. Effect of 5% glycolic acid complex and 20% glycolic acid on mild-to-moderate facial acne vulgaris. Chinese Medical Journal. 2022 Nov 5;135(21):2614–6.
Kornhauser A, Wei RR, Yamaguchi Y, Coelho SG, Kaidbey K, Barton C, et al. The effects of topically applied glycolic acid and salicylic acid on ultraviolet radiation-induced erythema, DNA damage and sunburn cell formation in human skin. Journal of Dermatological Science. 2009 Jul;55(1):10–7.
Kaidbey K, Sutherland B, Bennett P, Wamer WG, Barton C, Dennis D, et al. Topical glycolic acid enhances photodamage by ultraviolet light. Photodermatology, Photoimmunology & Photomedicine. 2003 Feb;19(1):21–7.
Tian Y, Li XX, Zhang JJ, Yun Q, Zhang S, Yu JY, et al. Clinical outcomes and 5-year follow-up results of keratosis pilaris treated by a high concentration of glycolic acid. World Journal of Clinical Cases. 2021 Jun 26;9(18):4681–9.
Narda M, Trullas C, Brown A, Piquero‐Casals J, Granger C, Fabbrocini G. Glycolic acid adjusted to pH 4 stimulates collagen production and epidermal renewal without affecting levels of proinflammatory TNF‐alpha in human skin explants. Journal of Cosmetic Dermatology. 2020 Jul 24;20(2):513–21.
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. Dermatologic Surgery. 2001 May;27(5):429–33.
Sharad J. Glycolic acid peel therapy – a current review. Clinical, Cosmetic and Investigational Dermatology. 2013 Nov;6:281.
BURNS RL, PREVOST-BLANK PL, LAWRY MA, LAWRY TB, FARIA DT, FTVENSON DP. Glycolic Acid Peels for Postinflammatory Hyperpigmentation in Black Patients. Dermatologic Surgery. 1997 Mar;23(3):171–5.
Fatemeh Esnaashari, Dorna Rostamnejad, Hossein Zahmatkesh, Rahmani FA, Zamani H, Behnam Rasti. Diclofenac Sodium‐Encapsulated Poly(lactic‐co‐glycolic acid) Nanoparticles: A Non‐antibiotic Formulation to Attenuate the Proteolytic Activity of P. aeruginosa Clinical Isolates. ChemistrySelect. 2024 Jan 9;9(2).