the discovry of minoxidil molecule

The use of minoxidil for hair loss has an important history. It was first used during the 1970 as an oral medication for refractory cases of high blood pressure. The molecule is a piperidinopyrimidine derivative, with the chemical structure 2,6-diamino- 4-piperidinopyrimidine 1-oxide .

 It serves as an arteriolar vasodilator, acting specifically to open potassium channels. It also was found to have a side effect of hypertrichosis. , it was found to cause unwanted hair growth in 24% to 100%  of patients. Hypertrichosis was also noted in 5 out of 6 patients treated with minoxidil.  hypertrichosis is observed in a high frequency and at lower doses in women than in men No endocrine abnormalities have been associated, but darkening of the skin and the coarsening of facial features have been reported from long-term oral use.

Hypertrichosis caused by minoxidil was not reported in the dermatology literature until 1979 That same year, the oral tablet form, Loniten (Pharmacia & Upjohn, Bridgewater, NJ), was approved by the FDA for hypertension. Other dermatologists quickly took note in considering it for use in treating different forms of hair loss. Zapacosta  noted a reversal of androgenetic alopecia (AGA) in a patient receiving oral minoxidil. However, there were limitations to using the oral formulation, because it could cause an unsafe drop in blood pressure. Patients also experienced side effects of severe water retention and weight gain, often requiring concomitant treatment with a diuretic.

Therefore, several researchers tested its use as a topical formulation for hair loss. Two controlled trials using 1% topical minoxidil for alopecia areata (AA) demonstrated cosmetically acceptable regrowth in approximately half of patients. In 1984, topical minoxidil was used for the treatment of AGA. Five patients with AGA and 10 with AA were randomized to 1% or 5% topical minoxidil or placebo. Regrowth was seen in the 3 patients with AGA who were given the 5% solution, suggesting a clinical dose response. Blood levels of minoxidil were 0.5, 2.0, and 4.5 ng/mL 2 hours after application to the scalp. None of the patients with AA regrew hair, despite comparable blood levels.