Inclusion Criteria:  Male, 21-45 years of age Serum testosterone concentration < 300 ng/dl measured on two separate occasions (separated by at least one week), with collection prior to 10AM  Exclusion Criteria:  Serum testosterone concentration > 300 ng/dl Abnormal serum prolactin (PRL) concentration (PRL > 15.2 ng/ml) Concurrent or prior use of hormone-modifying medications (clomiphene citrate or other SERM, testosterone replacement therapy or other testosterone-containing products/treatments, gonadotropin therapy, aromatase inhibitors, estrogen-containing products/treatments) Documented karyotype abnormality Diagnosis of Kallmann syndrome Any prior chemotherapy, radiation therapy to the groin/pelvis, or known exposure to gonadotoxic agents History of cryptorchidism or prior orchiopexy History of testicular cancer or prior orchiectomy History of pituitary tumor or resection of pituitary tumor History of prostate cancer or severe benign prostatic hypertrophy History of epididymitis or epididymo-orchitis, or orchitis (including mumps) History of primary hypogonadism History of prior urinary tract infection History of intravenous drug use Any of the following comorbidities: renal insufficiency, heart disease, peptic ulcer disease, cerebrovascular disease, liver disease, psychiatric disorders, chronic pain, bleeding diatheses, anemia, polycythemia, vision problems Medical history or concurrent illness that the investigator considers sufficiently serious to interfere with the conduct, completion, or results of this trial, or constitutes an unacceptable risk to the subject Documented allergy or hypersensitivity to clomiphene citrate or other SERM