What is Testosterone

Testosterone is the most important androgen (male sex hormone). You need it to have normal reproductive and sexual function. Testosterone is important for the physical changes that happen during puberty, such as the development of the penis, testicles, facial and body hair, and muscle growth. Testosterone acts on cells in your testicles to make sperm. Testosterone is also important for overall good health. It helps the growth of bones, and affects your mood and sex drive. Some testosterone is changed into oestrogen, the female sex hormone, and this is important for your bone health.