Minoxidil is the most widely used topical treatment for hair loss and one of only two medications with robust clinical evidence for male pattern baldness. It is available without prescription in the UK and relatively inexpensive — which has contributed both to its widespread use and to significant misunderstanding about what it can and cannot achieve.
Minoxidil was originally developed as an oral medication for high blood pressure. Patients using it noticed an unexpected side effect: hair growth on the scalp and elsewhere on the body. This led to the development of a topical formulation specifically for the scalp, which became the first hair loss treatment approved by the FDA.
It works by prolonging the anagen (growth) phase of the hair cycle and increasing blood flow to follicles. Unlike finasteride, it does not address the hormonal cause of hair loss — it does not affect DHT. This means it is useful for promoting growth and maintaining existing hair, but does not slow the underlying miniaturisation process in the same way as finasteride.
Available as a 2% or 5% solution and as a foam, the 5% strength produces more significant results in most studies. It must be applied twice daily to dry scalp and left for four hours before washing. Consistency is the key variable — many patients who report minoxidil not working have been inconsistent in their application routine.
Like finasteride, minoxidil must be used continuously. Stopping treatment typically results in loss of the hairs it was maintaining within three to six months.
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