Melatonin is a hormone produced in the pineal gland of mammals that aids in the regulation of sleep/wake cycles.*  This product is specially designed to mimic the typical nighttime release pattern of melatonin.  The first stage releases approximately 0.25 mg of melatonin within 30 minutes followed by a delayed release of the remainder about 3 to 4 hours later.  NOW® Melatonin is synthesized according to the highest pharmaceutical standards of quality and purity.