Hypogonadism

Inclusion Criteria

- Men aged 50 years and older
- Symptomatic hypogonadism as defined by a) and b):
  - a) Total testosterone below 12nmol/l
  - b) Aging males symptom score above 36
- Willing to avoid significant change in the pattern of physical exercise and   lifestyle for the duration of the study
- Willing to voluntarily sign a statement of informed consent to participate in the study.

Exclusion Criteria

- Use of androgen therapy or anabolic steroids 
- Suspicion or known history of liver tumors,   prostate or breast cancer 
- Hypersensitivity to the active substances or any of the excipients of NEBIDO e.g. Benzyl benzoate and castor oil. Hypercalcemia accompanying malignant tumors
- Blood coagulation irregularities presenting an increased risk of bleeding after intramuscular injections sleep apnea
- Polycythemia
- Hematocrit level >50% at entry to the study (i.e. screening visit/visit 1)
- Patients using 5-a-reductase inhibitors such as finasteride or dutasteride should be excluded from the study.
- Prolactin level >25ng/ml 
- Organic hypothalamic-pituitary pathology
- Prostate specific antigen (PSA) level ≥ 4ng/ml
- Severe symptomatic benign prostatic hyperplasia (IPSS sum score ≥ 20) 
- Epilepsy not adequately controlled by treatment
- Migraine not adequately controlled by treatment
- Patients requiring or undergoing fertility treatment
- Any clinically significant chronic disease that might, in the opinion of the investigator, compromise patient's safety interfere with the evaluations, or preclude completion of the trial (e.g. hemochromatosis, chronic lung disease, chronic malabsorption disease)
- Known history of alcohol or drug abuse
- Medical, psychiatric or other conditions that compromise the patient's ability to understand the patient information, to give informed consent, to comply with the trial protocol, or to complete the study.
- Hypertension which is not adequately controlled on therapy
- Severe cardiac, hepatic or renal insufficiency
- Coronary heart disease not stabilized by therapy as assessed by the investigator
- Metal implants in the body (metal implants in the head will not exclude patients from participation)
- Concomitant participation in another clinical trial within 1 month of entry into this study (i.e. randomized and has taken study medication).