Minoxidil
Status
FDA-approved. FDA-approved labeling exists for topical minoxidil over the counter for androgenetic alopecia in men and women. Oral minoxidil tablets are approved only for severe hypertension refractory to other treatment and carry a boxed warning covering pericardial effusion, tamponade and angina exacerbation; use of oral minoxidil for hair loss is off-label.
What it is
A topical or oral medicine used for hair density.
What published research measured
Originally an oral vasodilator antihypertensive, repurposed topically for hair loss after hypertrichosis was observed as a side effect. Topical minoxidil has a large randomized evidence base and over-the-counter approval, and it works by prolonging the anagen growth phase; response requires several months and reverses on stopping. It is a prodrug requiring sulfotransferase activation in the follicle, which is the leading explanation for why a substantial minority do not respond. Low-dose oral minoxidil has become widely used off-label with growing observational evidence and better adherence than topical, but it retains the cardiovascular pharmacology of the antihypertensive: the oral tablet carries a boxed warning for pericardial effusion progressing to tamponade, and fluid retention and reflex tachycardia are dose-related.
Source
FDA labeling for topical minoxidil and for oral minoxidil, including the boxed warning
Sources
No linked primary source is on file for this entry yet.
Educational use only, never medical advice. No doses.