L-Tryptophan
A PubMed database search was conducted and a total of 18 articles were collected.
The results of the study suggested that Tryptophan supplementation may shorten the wake time after falling asleep. In addition, the group that received ≥1 gram Tryptophan supplementation had a shorter wake after sleep onset than the group with Trp < 1 g supplementation. However, tryptophan supplementation did not affect other sleep components.
Tryptophan is safe to use for better sleep.