Serotonin

It is a neurotransmitter in the central nervous system. Its share in the brain where it plays the role of neurotransmitter represents only 1% of the total present in the body, but it plays a key role. It is involved in the regulation of functions such as thermoregulation, eating and sexual behaviors, the sleep-wake cycle, pain, anxiety or motor control.
Serotonin is derived from Tryptophan and synthesizes Melatonin, a neurohormone.