Testosterone, Metformin, or Both, for Hypogonadism in Obese Males

Inclusion Criteria:

• Men aged 18 to 50 years.

• BMI > or = 30 kg/m2.

• Total testosterone levels <2.3 ng/ml (<8 nmol/l) or testosterone levels 2.3-3.49ng/ml (8-12 nmol/l) and free testosterone levels <70 pg/ml.

• LH levels <7.7 mIU / ml.

• No evidence of any other pituitary hormone disruption in morning blood sample (normal concentrations of TSH, FT4, Prolactin, ACTH, cortisol and IGF-1

• Being able to provide informed consent before randomization and agree to comply withall the procedures included in the protocol.

Exclusion Criteria:

• Intolerance/allergy to metformin or testosterone undecanoate.

• Previous diagnosis of diabetes mellitus (HbA1c> 6.5% or fasting glucose> 126 mg/dlor glucose> 200 mg/dl after an oral glucose tolerance test)

• Treatment with oral hypoglycemic agents, insulin or GLP-1 analogs.

• Poor kidney function: serum creatinine> 2.0 mg / dl.

• Previous history of prostate cancer or breast cancer.

• Active cancer of any kind.

• History of liver tumor or acute or chronic liver disease with impaired liverfunction: total bilirubin> 2.0 mg / dl or GOT levels three times the upper limit ofnormal.

• Central hypogonadism of organic cause

• Use in the past 12 months of any drug that affects the pituitary-gonadal axis.

• Use of oral testosterone, oral or transdermal within 2 weeks prior to study entry,or any testosterone ester in the last 6 weeks or testosterone undecanoate injectionin the 6 months prior to study entry.

• Uncontrolled hypertension (SBP> 160 mmHg or DBP> 100 mmHg) despite adequateantihypertensive therapy.

• HIV infection or known active infection with HBV or HCV.

• Thrombotic or embolic disease.

• Heart disease, kidney or liver disease.

• Epilepsy or migraine not adequately controlled with treatment.

• Hematocrit> 50% in the screening.

• PSA> 4 ng / ml.

• Severe benign prostatic hypertrophy with an IPSS scale score over 19.

• Evidence of drug or alcohol abuse (> 50 g alcohol / day)

• Hematological diseases that produce increased risk of bleeding after intramuscularinjection.

• Serious underlying disease that might affect the patient's ability to participate inthe study (eg ongoing infection, gastric ulcers, active autoimmune disease).

• Reduced life expectancy (<12 months) by the presence of comorbidities or advancedterminals.

• Participation in another clinical trial within 30 days before study entry.

• Previous diagnosis of hemochromatosis

• Treatment with phosphodiesterase-5 inhibitors: sildenafil, tadalafil or vardenafil