@Ragman,
sorry..a correection...that should read "was used to TREAT high blood pressure.
"Minoxidil was first used exclusively as an oral drug (trade name Loniten) to treat high blood pressure. It was, however, discovered to have the interesting side-effect of hair growth and reversing baldness."
... it is a blood vessel dilator.
"Treatments usually include a 5% concentration solution that is designed for men."
...
"Minoxidil is less effective when there is a large area of hair loss. In addition, its effectiveness has largely been demonstrated in younger men (18 to 41 years of age) and in those with balding in the central (vertex) portion of the scalp."
...
Side-Effects
"If a person uses minoxidil to stop hair loss for a length of time and then stops taking the drug, hair loss will occur again.
Other side-effects include:
acne on the area where it is being used as a topical solution
headaches and/or lightheadedness
very low blood pressure
irregular or fast heart beat
blurred vision or other vision problems
decreased sexual desire
partial, or complete, impotence
numbness or tingling in the hands, feet or face
rapid weight gain
chest pain"