Melatonin

Melatonin is derived from L-tryptophan and serotonin released into circulation immediately upon synthesis. It is so important to have a darkened bedroom, light inhibits melatonin production. Being human we are meant to walk and exercise in daylight, let the light in, and sleep in the very dark, be in deep rest, allowing the secretion of lots of melatonin.

  • from The Third Edition of The Practicing Herbalist