The overall objective of this randomized trial is to investigate the effects of treatment of AAS- induced male hypogonadism with combined therapy of letrozole and hCG compared with placebo on reproductive hormone levels, adherence to cessation of AAS use, fertility, cardiac function and quality of life.

A randomized, double-blinded, clinical, placebo-controlled trial enrolling 60 male illicit AAS users with documented AAS-induced hypogonadism after a period \> 12 weeks of AAS cessation or a negative urine AAS doping test. Participants will be randomized to two study groups; 24 weeks of treatment with either tablet letrozole (femar®) initial dose of 2.5 mg each day versus tablet placebo. After an initial treatment period of four weeks, intramuscular injections with either hCG, initial dose 1500 IE twice weekly (letrozole group) or isotonic saline twice weekly (placebo group) will be added to therapy if plasma total testosterone level has not increased to target plasma level. Following 24 weeks of therapy, all participants will be observed for another 26 weeks without therapy. The study will have one trial center of recruitment: Department of Endocrinology, Rigshospitalet. Following participation in the study, all participants will be offered referral to an endocrine outpatient clinic if they still display clinical and biochemical signs of male hypogonadism. A healthy group of 30 young lean eugonadal men, who have never used AAS, will be enrolled as control participants and undergo a screening visit and one visit including same procedures as the screening and randomization visits.