Determine the serum pharmacokinetic profile for two oral formulations of T-esters (one TE and one TU) administered once -(QD) and twice-daily (BID) to hypogonadal men.

Five period cross-over study in which subjects received a single day of dosing in each period. Dosing was either QD or BID with one of two T esters (T-enanthate (TE) or T-undecanoate (TU)). Dosing was within 5 minutes of meals (breakfast and for BID dosing dinner). There was a minimum of a 5-day washout between periods. Subjects were hypogonadal men.

Inclusion Criteria:

Male, ages 18 to 65 Serum total testosterone less than or equal to 250 ng/dL Naive to androgen replacement therapy Subject must be on stable doses of thyroid or adrenal replacement hormones for at least 14 days prior to enrollment

Exclusion Criteria:

Significant intercurrent disease of any type, in particular, liver, kidney or heart disease, uncontrolled diabetes mellitus or psychiatric illness. Patients with treated hyperlipidemia will not be excluded provided they have been stable on their lipid-lowering mediation for at least three months. For non-insulin dependent diabetic subjects, HbA1c>9%.

Abnormal prostate digital rectal examination, elevated PSA (serum PSA >4ng/mL), AUA Sympton Score greater than or equal to 15 points, and a history or prostate cancer.

Serum transaminases >2X upper limit of normal (ULN) or serum bilirubin >2.0 mg/dL.

History of severe or multiple allergies, severe adverse drug reaction or leucopenia. Known hypersensitivity to lidocaine or all surgical dressings.

History of abnormal bleeding tendencies. Oral, topical, or buccal T therapy within the previous week, or intramuscular T injection within the previous 4 week.

Use of dietary supplements that may increase serum T, such as androstenedione or DHEA, within the previous 4 weeks.

Know malabsorption syndrome and/or current treatment with oral lipase inhibitors, bile acid-binding resins, colestipol, fibric acid derivatives, gemfibrozil, and probucol.

Smokers who are unable to refrain from smoking during confinement periods. History of, or current evidence of, abuse of alcohol or any drug substance. Poor compliers or those unlikely to attend. Receipt of any drug as part of a research study within 30 days of inital dose administration in this study.

Blood donation (usually 550 mL) within the 12-week period before the initial study dose.

Hematocrit less than 35%. Known clinical polycythemia or hematocrit greater than 50%. Current use of paroxetine and clomipramine, antiandrogens, estrogens, p450 enzyme inducers, or barbiturates.

History of sleep apnea.

Subjects received doses on 5 dosing days spanning approximately 4 weeks.