Melatonin-SR offers sustained-release MicroActive^® melatonin to promote healthy sleep. Melatonin is a hormone produced by the pineal gland, which regulates the body's sleep/wake cycle. Melatonin's primary role is regulation of the body's circadian rhythm, endocrine secretions and sleep patterns. Studies indicate that it facilitates the onset of sleep as well as sleep efficiency, providing specific support to shift-workers, international travellers and people with delayed sleep phase disorder. MicroActive^® melatonin is an innovative, patented delivery system that offers both improved absorption and sustained release. A pharmacokinetic study of MicroActive^® melatonin demonstrates rapid uptake and prolonged presence in plasma up to six hours after a single dose.