The purpose of this study is to evaluate the safety and efficacy of Testogel® 50mg/5g gel administered once daily (QD, morning dosing) compared to placebo administered once daily (QD, morning dosing), for 3 months, in hypogonadal men with testosterone deficiency being confirmed by clinical features and biochemical tests. For men with hypogonadism, treatment aims to restore testosterone levels to normal physiological range.

Inclusion Criteria:

• Male ages 18-68 years diagnosed as having testosterone deficiency with clinical symptoms
• A morning (8:00-10:00) serum Total Testosterone concentration of ≤ 300 ng/dL, confirmed by a second measurement of morning serum Total Testosterone concentration ≤ 300 ng/dL (samples to be taken 1 - 3 weeks apart)

Exclusion Criteria:

• Abnormal prostate as evidenced by prostatic symptoms, prostatic masses or induration on rectal examination, or elevated levels of prostate specific antigen (PSA > 4ng/ml) or a maximum urine flow rate of less than 12 ml/sec(of a urine volume greater than 150ml) (and/or an International Prostate Symptom Score IPSS score >19)
• Hematocrit > 50%
• Major psychiatric illness
• Unable to understand the protocol or to give informed consent
• Use of paroxetine and clomipramine
• Active alcoholism
• History of drug abuse within the past five years;
• Use of drugs that might interfere with the results of the study (e.g., antiandrogen, estrogens or P 450 enzyme inducers, barbiturates);
• BMI < 18 or > 30 according to Chinese BMI references;
• Generalized skin disease that may affect absorption of T (e.g., psoriasis) or a known skin intolerance to alcohol;
• Prolactin > 40 mcg/L;
• Untreated severe obstructive sleep apnea;.
• Uncontrolled or poorly controlled heart failure