N-Des(1,1-dimethylethyl) N-Cyclohexyl Finasteride-d11 is the isotope labelled analog of N-Des(1,1-dimethylethyl) N-Cyclohexyl Finasteride (D289575); an impurity of Finasteride (F342000) which is an inhibitor of 5α-reductase, the enzyme that converts testosterone to the more potent androgen 5α-dihydrotestosterone.Also an antialopecia agent.