Minoxidil

Minoxidil was first introduced in tablet form for the treatment of high blood pressure. Some of the patients noticed an increase in hair growth, also known as hypertrichosis, as a side effect. Shortly after, scientists began applying it to the scalp to stimulate hair growth.

2% topical Minoxidil(Rogaine®) was FDA-approved as a prescription in 1988. It wasn't until 1996 that it was offered as an over-the-counter product. In 1998, 5% Monoxidil was approved for OTC use. Clinical trials show rapid increases in hair growth following usage of 2% and 5% Minoxidil. This effect is usually seen with six to eight weeks after the start of treatment.

Mechanism of Action

It has been known for 30 years that minoxidil stimulates hair growth, yet the action on the hair follicle is not completely understood. In animal studies, topical treatment with minoxidil seems to shorten the telogen phase. This in turn causes premature entry of resting hair follicles into anagen, which is thought to have a similar action in humans. It is also believed that minoxidil causes prolongation of anagen and increases hair follicle size. Another possible mode of action is minoxidil's ability to lower blood pressure. Minoxidil contains a sulphated metabolite called minoxidil sulphate, which is used to open up sarcolemmal KATP channels. This opening of potassium channels is where some believe minoxidil gets its stimulatory effect on hair growth. This theory has never been proven, and as of this writing there are no clear studies demonstrating that KATP channels are expressed in the hair follicle.

Side Effects

Minoxidil may have the following side-effects:

scalp itching
dryness
scaling
flaking
irritation
burning

Call your doctor immediately if any of these symptoms are severe or do not go away! If you experience weight gain, swelling of the extremities,face,or stomach,rapid heartbeat and/or chestpain, call you doctor immediately!