Pharmacokinetic Evaluation of Serum Testosterone Concentrations After Administration of Clomiphene Citrate

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