Subjects will be randomized into 4 study groups: 1. Placebo; 2. Anastrazole and Testosterone; 3. Dutasteride and Testosterone; and 4. Testosterone only. A 2 step euglycemic clamp, body composition by dual X-ray absorptiometry scan, hormone and lipid assays will be performed to monitor metabolic effects of each treatment group. We hypothesize that increasing testosterone levels would increase lean mass, decrease fat mass and improve insulin sensitivity. We further hypothesize that improvements in the metabolic profile would decrease with anastrazole and improve with dutasteride, given in conjunction with T administration.

Inclusion Criteria:

• free T level in the lower 25% of the normal range or below
• BMI ≥30kg/m2
• waist circumference ≥100cm

Exclusion Criteria:

• pituitary tumors
• HIV infection
• Klinefelter's syndrome
• Kallman's syndrome
• uncontrolled hypertension
• diabetes
• congestive heart failure
• chronic lung disease
• acute coronary syndrome
• PSA >4µg/L
• aspartate aminotransferase (AST)> 3x upper limit of normal
• use of medications that might affect weight loss, muscle or bone metabolism or androgen metabolism, action or clearance.
• involvement in daily resistance training or high endurance exercise
• alcohol or drug dependence
• obstructive sleep apnea