Evaluation of the therapeutic effects of AGA drugs by measuring finasteride, dutasteride, and dihydrotestosterone in hair

Androgenetic alopecia (AGA) is treated by 5α-reductase inhibitors (5ARI) such as finasteride and dutasteride, which are widely used as therapeutic agents. However, their pharmacokinetics in target organs (scalp and hair follicles) have not yet been investigated. To confirm the effective action of finasteride and dutasteride in the hair follicle tissues, we developed a method to measure these concentrations in hair. Compared to the non-detection (N.D.) group, the dihydrotestosterone (DHT) concentrations decreased significantly in both the finasteride and dutasteride groups. The dutasteride group showed significantly lower DHT concentrations among all groups. Measurement of finasteride, dutasteride, and DHT concentrations in hair would aid in evaluating the drug pharmacokinetics and its therapeutic effects on AGA patients.