What are the benefits of glycolic acid?

Thanks to its low molecular weight, glycolic acid has a very strong ability to penetrate the skin. Its main action is keratolytic, meaning that it breaks the bonds between corneocytes, the dead cells of the stratum corneum, thereby making it easier for them to be shed. By clearing pores of accumulated cellular debris, it helps prevent the formation of comedones and blemishes in general. In addition, by accelerating cell turnover, glycolic acid helps smooth surface irregularities, resulting in a more refined skin texture.

Several scientific studies have sought to evaluate the effectiveness of glycolic acid on acne‑prone skin. In a double‑blind clinical trial involving 26 patients with acne, participants applied a 40% peel to one half of their face and a placebo solution to the other. After five sessions spaced two weeks apart, the results showed a statistically significant reduction in acne lesions on the side of the face treated with glycolic acid compared with the placebo side. The study emphasized that this active ingredient was particularly effective on non‑inflammatory lesions, such as blackheads, and that it led to a marked decrease in sebum secretion as early as the eighth week of treatment.

Glycolic acid is one of the benchmark active ingredients used to target skin imperfections.

The action of glycolic acid on dark spots also relies on its exfoliating power. By breaking down desmosomes, the “bridges” that hold corneocytes together, it promotes the elimination of melanin-loaded cells that have accumulated on the surface of the epidermis. This accelerated cell turnover helps bring healthy skin layers to the surface and evens out the distribution of pigment. In addition, it smooths the stratum corneum, which then reflects light more effectively.

Glycolic acid combats both pigment spots and dull complexion.

The effectiveness of this active ingredient was evaluated in a comparative study against another reference depigmenting agent: azelaic acid. A study conducted on 40 patients with hyperpigmentation compared the daily use of a cream containing 12% glycolic acid with a cream containing 10% azelaic acid over a twelve-week period. The results show that although azelaic acid produces visible effects more quickly (as early as the fourth week), glycolic acid provides significant improvement starting from the eighth week of treatment. By the end of the study, both active ingredients were considered equally effective at reducing the appearance of pigment spots.

Thanks to its exfoliating properties, glycolic acid is an ally for restoring an even complexion and radiant skin.

Glycolic acid is a benchmark active ingredient for correcting the signs of photoaging thanks to its dual epidermal and dermal action. In addition to stimulating epidermal renewal, glycolic acid stimulates fibroblast activity to restart the production of collagen and glycosaminoglycans, such as hyaluronic acid. By densifying the extracellular matrix, glycolic acid restores the skin’s elasticity and firmness and helps gradually fill in wrinkles. A study conducted on human skin explants specifically highlighted these mechanisms. After five days of applying creams containing between 8% and 25% glycolic acid, researchers observed an increase in cell proliferation in the epidermis, as well as a significant rise in collagen levels.

These effects observed in the laboratory have also been confirmed by clinical evaluations in volunteers. A double-blind, placebo-controlled study was conducted in 41 participants to assess the impact of a 50% glycolic acid peel on photoaging. Participants received a weekly application for 4 weeks on one half of the face, the forearms, and the hands. The results showed a significant improvement in skin texture and a reduction in fine lines, as well as a lightening of age spots. From a histological standpoint, biopsies confirmed a thinning of the stratum corneum along with a thickening of the epidermis and, in several volunteers, an increase in collagen thickness in the dermis.

The use of glycolic acid peels not only produces an immediate visible improvement in the skin, but also triggers a deep restructuring of the tissues to counteract the effects of photoaging.

While glycolic acid is often associated with exfoliation, its action also contributes to the skin’s long-term resilience. By stimulating cellular metabolism, it induces a thickening of the epidermis, thereby increasing the skin’s natural protection. This process is accompanied by an increased synthesis of glycosaminoglycans and hyaluronic acid, sponge-like molecules capable of retaining water within the tissues. This hydration, combined with a more robust epidermal structure, optimizes the skin’s barrier function, making it better able to defend itself against external aggressors and to limit transepidermal water loss.

• KULKARNI Y. & al. A comparative study of the efficacy and safety of 12% glycolic acid cream and 10% azelaic acid cream in the treatment of post acne hyperpigmentation. Indian Journal of Research (1991).

• MOY R. & al. Clinical improvement of photoaged skin with 50% glycolic acid: A double-blind vehicle-controlled study. Dermatologic Surgery (1996).

• STANTON-HICKS U. & al. Improving the cosmetic appearance of photoaged skin with glycolic acid. Journal of the American Academy of Dermatology (1997).

• FURUKAWA F. & al. Effects of alpha-hydroxy acids on the human skin of Japanese subjects: The rationale for chemical peeling. The Journal of Dermatology (2006).

• MOGHIMIPOUR E. Hydroxy acids, the most widely used anti-aging agents. Jundishapur Journal of Natural Pharmaceutical Products (2012).

• ABELS C. & al. Cosmetic and dermatologic use of alpha hydroxy acids. Journal der Deutschen Dermatologischen Gesellschaft (2012).

• YAMOMOTO Y. & al. Clinical evaluation of glycolic acid chemical peeling in patients with acne vulgaris: A randomized, double-blind, placebo-controlled, split-face comparative study. Dermatologic Surgery (2014).

• ROTSZTEJN H. & al. Comparative study of 15% trichloroacetic acid peel combined with 70% glycolic acid and 35% trichloroacetic acid peel for the treatment of photodamaged facial skin in aging women. Journal of Cosmetic Dermatology (2019).

• FABBROCINI G. & al. 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).