The purpose of the study is to determine if oral testosterone undecanoate is effective and safe in the treatment of low testosterone in men.

Inclusion Criteria:

• Serum testosterone of less than or equal to 300 ng/dL (the mean of two samples collected 1 hour apart in the morning between 6:00 and 10:00 AM)

Exclusion Criteria:

• Significant intercurrent disease of any type, in particular liver, kidney, uncontrolled or poorly controlled heart disease including hypertension, CHF or CAD, or psychiatric illness including depression.
• Recent history of stroke, including transient ischemic attack (TIA) or acute coronary event
• Untreated, severe obstructive sleep apnea
• Hematocrit <35% or >48%
• Serum transaminases >2 times upper limit of normal, serum bilirubin >2.0 mg/dL, and serum creatinine >2.0 mg/dL
• BMI > or equal to 38
• Stable doses of lipid-lowering medication for less than three months
• Stable doses of oral medication for diabetes for less than two months
• Abnormal prostate digital rectal examination [palpable nodule(s)], elevated PSA (serum PSA >3.9 ng/mL), IPSS score > or equal to 19 points, and /or history of prostate cancer.
• History of breast cancer
• Use of dietary supplement saw palmetto or phytoestrogens and use of any dietary supplements that may increase serum T, such as androstenedione or DHEA with the previous 4 weeks
• Know malabsorption syndrome and/or current treatment iwht oral lipase inhibitors
• Known history of abuse of alcohol or any drug substance with the previous 2 years
• Current use of antiandrogens, estrogens, oral CYP3A4 inducers or inhibitors, or long-acting opioid analgesics
• Receipt of any drug as part of a research study within 30 days of initial dose administration in this study
• Blood donation within the 12 week period before initial dose administration in this study