Minoxidil

Minoxidil began as an oral antihypertensive whose hair-growth side effect was too consistent to ignore; the topical formulations developed from it became one of the two approved medical treatments for androgenetic alopecia, licensed for both men and women. Its mechanism at the follicle is still incompletely characterised — potassium-channel effects, changes in local blood flow and direct effects on the follicle cycle are all implicated — but its clinical behaviour is well described: it prolongs anagen and enlarges miniaturised hairs for as long as it is used.

The evidence tier for the topical route is high, with randomised placebo-controlled trials across several decades supporting increased hair counts and slowed progression in both sexes — and the drug’s limits are equally well documented. It works best in early to moderate thinning, requires conversion to its active form by a scalp enzyme (a sulfotransferase), which is one reason response varies between individuals, and its benefit lasts exactly as long as the application does. A temporary shedding phase in the first weeks, as follicles resynchronise, is common enough that every patient should be warned before starting.

Low-dose oral minoxidil has become a widespread off-label alternative where adherence to twice-daily topical use fails, with a growing published literature behind it. It brings systemic considerations — unwanted body hair, fluid retention, cardiovascular cautions in susceptible patients — and it sits squarely in physician territory: dosing, screening and follow-up are prescribing decisions for the treating doctor, not retail choices.

For clinics the operational duties are counselling and honesty. Patients need the timeline (months of use before assessment means anything), the adherence reality (the effect stops when use stops), the shedding warning, and correct positioning — minoxidil supports and thickens; it does not redraw a hairline, and it is not a substitute for diagnosing what the hair loss actually is. Documented counselling, standardised photographs at baseline and follow-up, and a referral path for prescriptions the clinic cannot itself issue are the minimum professional apparatus around an easily trivialised drug.