Minoxidil

Minoxidil, initially used for severe hypertension, has been found effective in promoting hair growth and halting hair loss in alopecia areata and androgenic alopecia when used topically. A study with 393 men demonstrated that a 5% minoxidil solution was significantly more effective than a 2% solution and placebo in increasing non-vellus hair count and scalp coverage over 48 weeks, despite causing more skin irritation. Side effects are typically localized, with systemic absorption being minimal, though cardiovascular side effects have been observed in rare cases. A large observational study with over 3 million subject-days of exposure showed no increased risk of major medical events. While long-term oral use can lead to systemic effects, these are reversible after discontinuation. Topical minoxidil is generally safe, with no evidence of increased risk of adverse pregnancy outcomes, but caution is still recommended.