How it works
Minoxidil opens ATP-sensitive potassium channels in the dermal papilla, the base of the hair follicle. That raises blood flow. It also moves follicles from telogen (resting) to anagen (growing). It works separately from male hormones (androgens).
The evidence
It's been used in clinics for decades. The 5% topical solution is standard for men. Women use 2% or 5%. In recent studies, low-dose minoxidil pills (0.25–5 mg) compared well with the topical. They may suit women who had trouble sticking with the topical.
Typical dosing
On the scalp: 1 mL of 5% solution, twice a day. As a pill (off-label for hair): 0.25–2.5 mg a day, with a clinician supervising.
Side effects
Common
- Scalp irritation (topical)
- Extra shedding at first (4–8 weeks)
Less common
- Facial hair growth (oral)
- Lightheadedness (oral)
Rare
- Fast heartbeat, water retention (oral, more likely at higher doses)
Drug interactions
- Blood pressure medicines: blood pressure may drop further (oral)
