Minoxidil, a vasodilator medication known for its ability to slow or stop hair loss and promote hair regrowth, was first introduced, exclusively as an oral drug, to treat high blood pressure. It was however discovered to have the important side-effect of increasing growth or darkening of fine body hairs; this led to the development of a topical formulation as a 2% concentration solution for the treatment of female androgenic alopecia or 5% for treating male androgenic alopecia. Minoxidil may also cause prolongation of anagen and increases hair follicle size.
Unfortunately the theory is that you need to continue its use to maintain results as measured changes disappear within months after discontinuation of treatment. The mechanism by which it promotes hair growth is not fully understood. Minoxidil prolongs the anagen stage of growth and increases hair follicle size . Minoxidil is a potassium channel opener, causing hyper polarisation of cell membranes and it is also a vasodilator, it is speculated that, by widening blood vessels and opening potassium channels, it allows more oxygen, blood and nutrients to the follicle. This can also cause follicles in the telogen phase to shed, usually soon to be replaced by new, thicker hairs in a new anagen phase. It needs to be applied regularly, once or twice daily, for hair gained to be maintained, and side effects are common. The most common adverse reactions of the topical .
Reaction to the formulation are limited to irritant and allergic contact dermatitis on the scalp.
Shampoos such as Nizoral or Selsun are recommended as a companion treatment as they contain Ketoconazole which is a type of antifungal medicine that can help to treat skin infections caused by a type of fungus or yeast. It generally comes in the form of a cream, ointment, or in this case, shampoo.