L-tryptophan works like a natural sleeping pill
Partially trueThe Claim
As the precursor of serotonin and melatonin, L-tryptophan is believed to make you fall asleep faster and sleep better overall.
Origin
Its biochemical role as a melatonin precursor and the popular 'turkey makes you sleepy' idea drive the belief.
What Science Says
A 2022 meta-analysis found that tryptophan supplementation shortened wake time after sleep onset, with a larger effect at doses of 1 g or more (SMD −1.08). However, it did not affect the other sleep components analyzed, and the pooled analysis was based on only 4 studies.
Verdict
Partially True