Phlebotomy Study of Testosterone Undecanoate

Inclusion Criteria: 1. Male, 18 to 65 years of age, inclusive, with a diagnosis of hypogonadism and a screening total serum T of \< 300 ng/dL. 2. Adequate venous access to allow blood sample collections via venous cannula. 3. Naïve to androgen-replacement therapy or willing to temporarily cease current T treatment and willing to remain off all forms of T except for study medication throughout study. 4. Voluntarily provide written informed consent to participate in this study. Exclusion Criteria: Subjects meeting any of the following exclusion criteria will not be eligible: 1. Significant intercurrent disease (especially liver, kidney, heart disease, uncontrolled diabetes mellitus or psychiatric illness) 2. Abnormal prostate digital rectal examination, elevated PSA (PSA \> 4 ng/mL), AUA Symptom Score ≥ 15 points and/or history of prostate CA. 3. BMI less than 18 kg/m2 or greater than 37 kg/m2 4. Serum transaminases \> 2 times upper limit of normal (ULN) or serum bilirubin \>2.0 mg/dL. 5. History of severe or multiple allergies, or severe adverse drug reaction. A known hypersensitivity to lidocaine or all surgical dressings which may be used in the study procedures. 6. History of abnormal bleeding tendencies or thrombophlebitis unrelated to venipuncture or intravenous cannulation. 7. Oral, topical or buccal T therapy within previous one week, or intramuscular T injection within previous 4 weeks. 8. Parenteral T-undecanoate therapy within the past 6 months. 9. Use of dietary supplements that may increase serum T, within previous 4 weeks. 10. Known malabsorption syndrome and/or current treatment with oral lipase inhibitors, bile acid-binding resins, colestipol, fibric acid derivatives, clofibrate, gemfibrozil, and probucol. 11. Smokers unable to refrain from smoking during required confinement period. 12. History of, or current evidence of, abuse of alcohol or any drug substance. 13. Receipt of any research study drug within 30 days of study. 14. Blood donation within the 12 week period before the initial study dose. 15. Hematocrit less than 35% or greater than 50%. 16. History of clinically significant polycythemia following treatment with a testosterone replacement product. 17. Current use of paroxetine, clomipramine, antiandrogens, estrogens, potent P450 enzyme inducers, or barbiturates. 18. History of uncontrolled sleep apnea.