OstroVit - Histidine is an amino acid...
An additional intake of 100% Premium Ultimate Nutrition Melatonin (Ultimate nutrition - melatonin) helps restore normal levels of melatonin in the body.
Swanson Melatonin contains melatonin, which helps control your sleep/wake cycle.
Swanson 5-HTP & Melatonin contains 5-HTP and melatonin, which regulates the sleep-wake cycle.