OstroVit - Histidine is an amino acid...
Melatonin is used to combat insomnia and to combat jet lag.
5-HTP (5-hydroxytryptophan) - an intermediate metabolite between the amino acid L-tryptophan and serotonin, obtained from the seeds of an African plant Griffonia simplicifolia.
Puritan's Pride - Melatonin contains melatonin, which is produced in the brain, a synonym for "sleep hormone".
Puritan's Pride - 5-HTP L-5-Hydroxy-Tryptophan helps increase serotonin levels.