Amino acids
L-tryptophan
Also called: tryptophan
An essential amino acid used to make serotonin and melatonin.
- Why people take it
- Sleep, mood.
- What the evidence says
- Limited evidence.
- How it is usually taken
- Usually 0.5 to 2 g a day.
- Be careful
- Do not combine with antidepressants or other serotonin drugs.
- Medicines it can interact with
- Serotonin syndrome risk with antidepressants, tramadol and triptans.
Other amino acids
Common questions
What is L-tryptophan?
An essential amino acid used to make serotonin and melatonin.
Why do people take L-tryptophan?
Sleep, mood.
Does L-tryptophan work?
Limited evidence.
How much L-tryptophan do people take?
Usually 0.5 to 2 g a day.
Is L-tryptophan safe?
Do not combine with antidepressants or other serotonin drugs.
Does L-tryptophan interact with medicines?
Serotonin syndrome risk with antidepressants, tramadol and triptans.
Sources and further reading
Last reviewed 31 October 2026. Written by Satya Babu.
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