Minoxidil (currently sold under the brand names of Rogaine, Loniten, Lonolox, Noxidil, Pilomin, Reten and more than 100 others) is a widely used medication for the treatment of hair loss.

It was originally developed (1950s) as an oral medication for stomach ulcers - for which it proved ineffective. During trials, however, it was discovered that the drug had a strong effect in lowering blood pressure, and was later approved as a treatment for hypertensionplugin-autotooltip__plain plugin-autotooltip_bigHypertension

Only 5 -10% of cases of hypertension (high blood pressure) have causes which can be clearly identified - e.g. due to narrowing of the arteries. Put another way, of those patients who have been identified as having abnormally high blood pressure, physicians will not be able to pinpoint a specific cause in more than 90% of cases.. (Because of its wide range of unpleasant side effects, it was normally only used when other medications had failed.)

One of its side effects was to induce hypertrichosis (excessive hair growth) in many patients. Thus it was subsequently adopted as as a hair growth stimulant in the form of external ointments. Which is now its main medical use.

In this respect, its mechanism of action is currently unknown.

The mechanism by which minoxidil, an adenosine-triphosphate-sensitive potassium channel opener, induces hypertrichosis remains to be elucidated. Minoxidil has been reported to stimulate the production of vascular endothelial growth factor, a possible promoter of hair growth, in cultured dermal papilla cells. The mechanism of production of vascular endothelial growth factor remains unclear, however.

Source :Journal of Investigative Dermatology Volume 117, Issue 6,