Testosterone is for the most part a male hormone produced by the testicles, although a smaller amount is produced by the adrenal glands. This hormone is responsible for the development of male physical characteristics, muscle mass, strength, fat distribution and sexual drive. Smaller amounts of testosterone are also produced by women in the ovaries and the adrenal glands. Testosterone production is stimulated by hormones such as leuteinizing hormone further up the chain starting at the hypothalamus in the brain.
To be more definitive, testosterone is an androgenic, anabolic, steroid hormone. ‘Androgenic’ means pertaining to male characteristics and ‘anabolic’ means building up or synthesizing body tissue. ‘Catabolic’ means breaking down tissue. Another important hormone, cortisol, is a catabolic hormone. A ‘steroid’ in broadest terms is a class of similarly structured chemicals produced by the body.
Testosterone is the number one hormone for bodybuilding and weight training, especially for the development of strength and muscle although this is not always the primary goal of weight training.