Minoxidil is a vasodilator that was used as an oral treatment for hypertension. It was discovered patients had an interesting side effect after using the treatment: they noticed hair growth, and hair loss stopped in people with alopecia (alopecia areata).
Following scientific research, a pharmaceutical company called Upjohn Corporation marketed minoxidil solution (Rogaine® in the U.S.) as a hair growth treatment that could be directly applied to the scalp.
This solution of minoxidil 2% has since fallen into the public domain and there are many generic (Alopexy®; Alostil®; Lonoten®; Unipexil®; Minoxidil). In 1998, a 5% solution of minoxidil was also marketed (Rogaine Extra Strength for Men® in the United States, Kirkland Minoxidil 5 %, Foligain.P5 Minoxidil 5%, 5% Alopexy® and Alostil® 5% in France).