Genotropin 5.3 mgs (16ui) is a form of human growth hormone. It is used to treat growth failure in children and adults due to inadequate growth hormone production, or in those with Prader-Willi Syndrome. It helps increase growth rate and adult height, maintain normal body composition, and improve muscle mass. It also may improve physical capacity and impact body composition, and mental and emotional well-being. Possible side effects include headaches, joint and muscle pain, fluid retention, and tingling of the hands and feet.