As part of the aging process in men, changes occur that are attributed to the decline of testicular function. Sex hormone concentrations decrease progressively, and may reach below normal levels after the age of 40. Androgen deficiency (male sex hormones) is expressed by varied and not very specific symptomatology, highlighting the manifestations of the sexual sphere. Unlike what happens in women, male andropause or menopause occurs slowly and progressively, its onset is insidious, its clinical presentation is more subtle and it is not a universal process in all men. This is why it is preferred to be called: late-onset hypogonadism. The proper diagnosis and treatment of these patients results in a significant improvement in quality of life, sexual function and metabolic parameters. In this book the author describes the symptoms and signs of this process, how to diagnose it, what treatment to follow, as well as some measures to prevent it and tips to increase testosterone levels naturally.