The effects of topical diazoxide on hair follicular growth and physiology of the stumptailed macaque

In 1990, a study involving 7 adult stumptailed macaques examined the effects of topical diazoxide, a vasodilator known to cause hypertrichosis, on hair growth over 16 months. Five macaques received a 5% diazoxide solution and two served as controls with a vehicle solution. The diazoxide-treated group showed significant hair regrowth, with hairs becoming longer, thicker, and darker, particularly in the upper central scalp region. Early responders within this group exhibited a notable increase in early to mid-anagen follicles and enlargement of late anagen follicles within 4 months, while late responders showed similar but less consistent changes. After ceasing treatment, hair patterns reverted to the pre-treatment bald state. Physiological parameters, including body weight, blood pressure, heart rate, serum levels of testosterone and dihydrotestosterone, as well as glucose regulation, remained unchanged, suggesting no systemic side effects. The study concluded that diazoxide can promote hair follicular regrowth in this macaque model, potentially offering a therapeutic approach for human androgenic alopecia without adverse metabolic effects.