Sarcopenia in the elderly.

Sarcopenia is the age-related loss of muscle. It leads to loss of muscle power, which in the end results in frailty and disability. There are numerous causes of sarcopenia. Treatment consists of resistance exercise and a leucine-enriched essential amino acid protein supplement. There is an emerging role for testosterone and other anabolic steroids. An activin II receptor soluble fusion protein is showing great potential to increase muscle mass and bone mineral density.