Glycine helps slow the degeneration of muscle tissue as one of three components needed to synthesize creatine, a compound crucial for energy flow within skeletal muscle. It is necessary for central nervous system function, and is needed for a healthy prostate. Glycine can help prevent epilepsy and has been used to treat bipolar depression. The body uses glycine to synthesize nonessential amino acids for the immune system. The right amount of glycine will provide energy but too much can displace glucose in the metabolic chain and cause fatigue.