What Does Testosterone Do ?. Simply put testosterone is an important sex hormone. Testosterone will manage processes in the male body. Processes like libido, energy, immune function, muscle development and bone health. Testosterone is what’s called a chemical messenger… it has control over the development of male sexual characteristics. It is also found in women, but in a lot smaller amounts. In women the adrenal glands and ovaries will produce small amounts of testosterone. Peak production will be around 20 years old, with slow decline every year after. For guys… as well as managing sperm… testosterone will also affect sex Continue reading… What Does Testosterone Do?