Effect of Ultraviolet Light on Topical Minoxidil-Induced Hair Growth in Advanced Male Pattern Baldness

In 1987, a 4-month single-blinded controlled pilot study with nine men with advanced male pattern baldness showed that while 2% topical minoxidil solution applied twice daily increased nonvellus hair growth on the scalp, the addition of ultraviolet light (UVB or PUVA) treatments twice weekly did not significantly enhance or adversely affect this hair growth. There were no significant changes in hair counts on the arm target areas, nor were there photoallergic reactions. One participant developed allergic contact dermatitis to minoxidil, but was able to continue treatment after a brief pause and application of topical steroids. The study concluded that UV light does not significantly impact the efficacy of minoxidil in treating male pattern baldness.