What are the benefits of glycolic acid for the feet?

Glycolic acid, derived from sugar cane, is a low-molecular-weight alpha-hydroxy acid with keratolytic properties, meaning it disrupts and dissolves the bonds between corneocytes in the stratum corneum, the outermost layer of the skin. This process encourages the shedding of dead skin cells, promotes exfoliation and reveals fresher, healthier skin beneath. Consequently, glycolic acid specifically targets rough, callused areas commonly 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 enhanced hydration softens the skin and increases its elasticity, reducing the likelihood of cracking and dryness. By refining skin texture and boosting 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 disrupt ionic bonds between skin cells, reducing 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 efficacy and safety of glycolic acid when applied to the skin, even in sensitive or compromised conditions.

In a study involving 15 women (mean age 57) with clinical sun damage on the dorsal forearm, participants applied a 20% glycolic acid solution twice daily for three months. The results demonstrated 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 ability to enhance skin hydration, thickness and structure. Notably, no irritation was observed at the 20% concentration, which is high compared with over-the-counter formulations. This underscores its safety for use on areas with thicker skin, such as the feet.

Another study evaluated the use of a pH 4 water-in-oil emulsion containing 10 % glycolic acid in 30 male participants, including older adults, people with diabetes and those with an average age of 30 with no history of skin disorders. It is well established that skin pH often increases due to factors such as diabetes and ageing, which can result in increased dryness and a compromised skin barrier. Over a 28-day period, participants applied the emulsion two to four times daily.

The findings indicated that when the emulsion was applied to the feet of participants with diabetes, there were notable improvements in the skin’s pH. The acidification of the skin’s surface aided restore corneocyte cohesion and promote epidermal homeostasis, demonstrating the efficacy of glycolic acid for compromised skin types. Furthermore, the study found that even healthy individuals without preexisting skin conditions experienced improvements, including enhanced barrier function and reduced dryness and sensitivity.

The feet are typically less sensitive than other regions, making glycolic acid an appropriate choice for most individuals. Research has demonstrated that concentrations of up to 20%, which exceed those found in standard non-prescription formulations, do not induce irritation on the arm and leg areas. Nonetheless, caution is advised. Avoid applying glycolic acid to open wounds, calluses, or particularly sensitive sites to prevent potential irritation or discomfort. For optimal results, apply the product to clean, dry skin, ideally after a shower when the skin is most receptive.

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

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

• Furukawa F et al. Effects of alpha-hydroxy acids on human skin in 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. et al. Comparative effects of retinoic acid or glycolic acid delivered in different topical formulations. BioMed Research International (2015).

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