Complementary and alternative medicines patients are talking about: melatonin.

Melatonin (N-acetyl-5-methoxytryptamine) is a hormone produced by the pineal gland in the brain in response to darkness. Melatonin is made available when tryptophan is converted to serotonin and then enzymatically converted to melatonin in the pineal gland. Serum levels are low during the day, with peak levels occurring from 2-4 am.