Topical Melatonin in Androgenetic Alopecia: Mechanisms of Action and Current Clinical Evidence

Androgenetic alopecia (AGA) is the most common cause of progressive hair loss and significantly affects patients’ quality of life. Although established therapies such as minoxidil and finasteride are effective for many individuals, their variable response rates, adverse effects, and adherence challenges have prompted the investigation of complementary treatment options. Melatonin, a hormone best known for regulating circadian rhythms, has emerged as a potential therapeutic agent because of its antioxidant, anti-inflammatory, antiapoptotic, and immunomodulatory properties. The presence of melatonin receptors in the scalp and hair follicles supports its biological role in maintaining follicular homeostasis and promoting hair growth. This narrative review summarizes the mechanisms by which topical melatonin may benefit patients with AGA, including reduction of oxidative stress, prolongation of the anagen phase, modulation of androgen receptor signaling, possible inhibition of 5-alpha reductase activity, and regulation of growth factors involved in follicular regeneration. Available preclinical and clinical studies suggest that topical melatonin can reduce hair shedding, improve hair density, and demonstrate an excellent safety profile, particularly in early-stage disease and as an adjunctive therapy. However, current evidence remains limited by methodological heterogeneity, emphasizing the need for large, well-designed randomized clinical trials to define its efficacy and clinical role.

Keywords: Melatonin, androgenetic alopecia, hair follicle, oxidative stress, anagen phase, topical therapy