What are the benefits of glycolic acid on the feet?

Glycolic acid, derived from sugarcane, is a small-molecule alpha-hydroxy acid with keratolytic properties, meaning it breaks down and dissolves the bonds between corneocytes in the stratum corneum, the uppermost layer of the skin. This action facilitates the shedding of dead skin cells, promoting exfoliation and revealing newer, healthier skin underneath. As a result, glycolic acid effectively targets rough, calloused areas often found on the feet.

Beyond its keratolytic activity, glycolic acid functions as a humectant. It attracts and binds water molecules to the skin cells, enhancing moisture retention. This improved hydration softens the skin and increases its elasticity, reducing the likelihood of cracking and dryness. By improving skin texture and enhancing its moisture levels, glycolic acid can help you maintain smooth, resilient skin.

Although the precise mechanism is not fully understood, glycolic acid is believed to interfere with ionic bonds between skin cells, decreasing their cohesion and promoting skin renewal. Furthermore, it has been shown to stimulate collagen production, thereby improving skin thickness and structure—key factors in maintaining healthy skin and reducing calluses.

Research supports the effectiveness and safety of glycolic acid when applied to the skin, even in sensitive or compromised conditions.

In a study involving 15 women with an average age of 57, with clinical sun damage on the posterior forearm, participants applied a 20% glycolic acid solution twice daily for three months. The results showed a 16.5% increase in viable epidermal thickness and a 54.7% increase in hyaluronic acid levels within the epidermis. Additionally, the papillary dermis saw a 9.4% increase in hyaluronic acid. The study also recorded a 2.8-fold increase in collagen gene expression, demonstrating glycolic acid’s capacity to enhance skin hydration, thickness, and structure. Importantly, no irritation was noted at the 20% concentration level, which is high relative to over-the-counter products. This highlights its safety for use on areas with thicker skin, such as the feet.

Another study evaluated the application of a 10% glycolic acid-containing pH 4 water-in-oil emulsion on 30 male participants, including elderly, diabetic, and individuals with an average age of 30 and with no history of skin disorders. It is well-established that skin pH often becomes elevated due to factors such as diabetes and aging, which can lead to increased dryness and a weakened skin barrier. Over a 28-day period, participants applied the emulsion 2-4 times daily.

The results showed that when the emulsion was applied to the feet of diabetic participants, there were notable improvements in skin’s pH. The acidification of the skin surface helped restore corneocyte cohesion and promoted epidermal homeostasis, demonstrating glycolic acid’s effectiveness for compromised skin types. Furthermore, the study found that even healthy individuals without pre-existing skin conditions experienced improvements, including enhanced barrier function and reduced dryness and sensitivity.

The feet are generally less sensitive than other areas, making glycolic acid a suitable option for most people. Research has shown that concentrations up to 20%, which exceed typical over-the-counter products, do not cause irritation on the arm and leg areas. However, you should still exercise caution. Avoid applying glycolic acid to open wounds, calluses, or particularly sensitive areas to prevent potential irritation or discomfort. For best results, apply the product to clean, dry skin, preferably after a shower when the skin is most receptive.

With AHA’s, it’s always best to start with lower concentrations. As your skin adjusts to the treatment, you can gradually increase the concentration. Combining glycolic acid application with regular moisturizing and protective practices, such as wearing socks and avoiding abrasive footwear, can maximize its benefits. With consistent use, noticeable improvements can typically be seen within a few weeks.

• VAN SCOTT E. & al. Glycolic acid treatment increases type I collagen mRNA and hyaluronic acid content of human skin. Dermatologic Surgery (2001).

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

• SHARAD J. Glycolic acid peel therapy – A current review. Clinical, Cosmetic and Investigational Dermatology (2013).

• LOPES R. A. & al. Comparative effects of retinoic acid or glycolic acid vehiculated in different topical formulations. BioMed Research International (2015).

• SCHRELM S. & al. Impact of a glycolic acid-containing pH 4 water-in-oil emulsion on skin pH. Skin Pharmacology and Physiology (2015)..