Background: Testosterone is the most important androgenic hormone in the male. Aging is closely associated with reduction of serum testosterone which can lead to reduced muscle mass, muscle strength, bone density, and depression. These symptoms may be counteracted by administration of testosterone. Objective: The purpose of this study was to examine the effects of hormone replacement in men with age-related testosterone deficiency. Method: We performed a systematic review using Randomised Controlled Trials (RCT).