What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
L-tryptophan benefits: where the science stands
Almost nobody has looked.
As of August 2026, 1,205 papers on PubMed mention L-tryptophan, but almost none put it to a real test. For sleep, the best evidence is just a combined review covering 4 trials, and they lean positive. Early signs, not proof. Every claim we checked is below.
1,205 papers on PubMed · evidence from 4 trials
Claim by claim
- SleepAlmost no real studies. What exists leans positive.
Pairs people ask about
The source we read
- 2022Meta-analysis · pools 4 trials · small benefit for sleepsource
Chosen as the strongest evidence out of 1,205 papers on PubMed. Every row links to its paper.
Fair questions
Does L-tryptophan work?+
Nobody can honestly say: almost no real studies exist, whatever the label promises.
Is L-tryptophan safe?+
No caution is recorded on this page. That is not a safety guarantee; the studies we read were not safety trials.
Why only 1 source, when PubMed lists 1,205?+
The 1,205 is every paper that mentions L-tryptophan in any way: animal studies, blood measurements, papers where it is a side note. The strongest sources are combined reviews, and each one already gathers every trial its authors could find. Our 1 cover 4 trials between them, and every one is linked above. Both counts are measured, not estimated.