Myalept is a powder medicine that must be mixed with a liquid. Myalept (metreleptin) is used together with diet to treat complications caused by leptin deficiency in people who have lipodystrophy (also called fat redistribution). Lipodystrophy (LIP-oh-DIS-tro-fee) is a problem with the way the body stores fat. Myalept is not for use in people who have lipodystrophy caused by taking medicine to treat HIV or AIDS. Myalept may also be used for purposes not listed in this medication guide.