Minoxidil Sulfate Is the Active Metabolite that Stimulates Hair Follicles

This study from 1990 found that minoxidil sulfate, a metabolite of minoxidil, is the active ingredient responsible for stimulating hair growth. The study demonstrated that sulfation of minoxidil is a critical step for its effects on hair growth and that drugs that block the formation of minoxidil sulfate also block the activity of the parent drug. The study suggests that other drugs that can be metabolized to an active sulfate might be expected to directly affect hair follicles.