Epidermal Growth Factor (EGF) is a peptide that plays a crucial role in cell growth, proliferation, and differentiation, especially in epithelial tissues. Its use in supporting or treating hair loss and thinning is based on its biological activity in stimulating the proliferation of keratinocytes and dermal papilla cells, which are essential for hair follicle health and cycling. Several in vitro and animal studies have shown that EGF can influence the hair growth cycle, with evidence suggesting it may promote the transition from the telogen (resting) to anagen (growth) phase of hair follicles. For example, research published in Annals of Dermatology (2016) and Molecules (2020) demonstrated that topical EGF increased hair shaft elongation and cell proliferation in mouse models.

However, clinical evidence in humans is limited. There are a few small-scale studies and case reports suggesting potential benefits, such as improved hair density after topical EGF application, but these studies often lack rigorous controls or have small sample sizes. Additionally, some research raises concerns that excessive EGF signaling might actually inhibit hair follicle development or contribute to hair follicle miniaturization under certain conditions. As such, while biological plausibility and preclinical findings are promising, robust, large-scale clinical trials are lacking. The current evidence base supports cautious optimism but does not yet provide strong scientific validation for the widespread use of EGF in treating hair loss.