HGH is commonly used in sports to cope with high performance demands and to gain an edge over the competitors, such as muscle size, strength and speed, injury recovery, stamina and low body fat. HGH increases regeneration of muscle, tendons and cartilage among many other tissues. HGH has a capacity to not only regenerate muscle tissue, but can also stimulate satellite cells (muscle stem cells) to increase a number of muscle cells or more accurately the number of nucleus in the muscle fibers. This contributes to the permanent size and strength growth capacity of muscles. For this reason it is preferred to anabolic steroids as the latter has a temporary increase in muscle performance, harsh side effects and does nothing to increase performance capacity. It is also sometimes added to maximize performance and reduce side effects, such as loss of hair, libido, unwanted fat gain or acne.