Posted by iHerb Customer on Aug 03, 2009 | Verified Purchase
I have been using L-tryptophan for sleep for years. And, what's nice about it is that I don't have a drug hangover in the morning. tryptophan is a precursor to serotonin so I also like to think that I am getting the added benefit of some mood enhancement. For sleep, I take 2 capsules about 2 hours before I want to be asleep. Works great for me!