L-Tryptophan
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L-Tryptophan. Essential amino acid precursor to serotonin and melatonin.
How it works. Hydroxylated to 5-HTP then decarboxylated to serotonin; competes with BCAAs for BBB transport.
What the research supports. 1 graded claims. Strongest: Improves sleep latency and mood (moderate).
How much to take. Typical dose: 1–3 g before bed.
Side effects and interactions. 1 medication interaction listed. Serious: Eosinophilia-myalgia (historical contaminated batch).
Stacking. Pairs well with Magnesium glycinate, L-theanine.
Forms. 1 forms. Pick one to open its profile.
Key studies. 8 studies cited. The strongest are listed with links to PubMed.
Community. Experiences from people who have tried L-Tryptophan. Anecdotes are not medical advice.
L-Tryptophan. Essential amino acid precursor to serotonin and melatonin.
What it is
Essential amino acid precursor to serotonin and melatonin.
Food sources
Goals
How it works
Hydroxylated to 5-HTP then decarboxylated to serotonin; competes with BCAAs for BBB transport.
Pathways
- Serotonin synthesis
- Kynurenine pathway
Effects
- +Serotonin synthesis supports
- +Sleep onset supports
What the research supports
Strong: consistent results across large trials or meta-analyses. Moderate: several trials, mostly positive. Limited: small or mixed studies. Preclinical: animal or cell research only.
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Side effects & interactions
Common side effects
- Drowsiness
Serious
- Eosinophilia-myalgia (historical contaminated batch)
Medication interactions
Serotonin syndrome risk.
Check any supplement–medication combination with your pharmacist before starting.
Combines with
Pairs well
- Magnesium glycinateComplementary GABAergic calming and improved sleep architecture.
- L-theanineReduces sleep latency without sedation.
Forms
Key studies
8 studies cited in total.
Opens current human and preclinical literature matching L-Tryptophan and "Improves sleep latency and mood". Filter by RCT, meta-analysis, or year on the results page.
Opens current human and preclinical literature matching L-Tryptophan and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.
Opens current human and preclinical literature matching L-Tryptophan and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.
Discussion
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