The anti-hypertensive drug minoxidil was shown in the early 1980's to stimulate new hair growth, and was eventually approved as a topical treatment for male pattern baldness, and baldness in women (specifically androgenetic alopecia, AGA). Minoxidil is known to act as an opener of potassium channels, but the mechanism by which it is effective on hair is unclear. It appears to convert vellus hairs, which are short, fine body hair to terminal hairs - fully developed regular hairs; it also appears to normalize the hair follicle, and to increase the growth phase of hair follicles. Minoxidil® is proven to help slow or stop hereditary hair loss in 4 out of 5 people. Some people will even grow new hair. For a minority of people it can even grow back lost hairs in the crown area (back of the head). Multiple clinical trials have demonstrated the efficacy of minoxidil in AGA: in most patients treated with topical minoxidil 2% or 3% for 12 months, hair counts increased, and in some patients hair counts continued to increase for some time afterwards. Topical minoxidil 2% nevertheless has only limited success and the individual response is highly variable.

Rogaine® for Men Extra Strength 5% starts to work in about 8 weeks of treatment; Rogaine® for Men Regular Strength works after up to 4 months of treatment.

The active ingredient in Rogaine® is minoxidil, which has undergone extensive medical testing for safety and effectiveness. Rogaine is typically applied topically on the scalp twice a day. Once usage is discontinued the hair loss which had been inhibited will resume and the re-growth hair will most likely be lost.

Minoxidil has not been approved for systemic use because of potentially serious side-effects, notably cardiovascular, due to its antihypertensive action, and because extraneous hair growth has occasionally been seen even with topically applied minoxidil thought to be due to absorption and systemic action. Individual users of Regular strength Rogaine have claimed success rates of 30-40%. Meanwhile, users of Extra Strength Rogaine have claimed success rates of 50-60%. Currently, the average price for a 2oz. bottle of Rogaine is about $20-30 per month. Rogaine originally required a prescription, but it is now available over the counter as Rogaine, or as generic Minoxidil without prescription. A small percentage of users, about 6%, experience scalp irritation with Rogaine, users can use a mild dandruff shampoo twice a week to help keep the scalp healthy. There may also be an increase in hair shedding at the start of the treatment, this is typically part of the hair growth cycle and may actually be a signal that the treatment is working. Users with severe, refractory high blood pressure experienced some problems. One such problem was hypertrichosis, hair growth on the face or other bodily areas. This side effect appears in about 3-5 % of women who use the 2% solution, and higher among women using the 5% solution. It's important to note that Rogaine (minoxidil) is not a cure for baldness. The real benefits of Rogaine (minoxidil) is stopping or slowing hair loss. Rogaine's success depends on how advanced your hair loss has become.