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SupplementScience

L-Tryptophan Side Effects & Safety

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Safe with Caution

Potential Side Effects

  • Drowsiness — expected effect when used for sleep
  • Nausea or GI discomfort at higher doses
  • Headache or lightheadedness in some individuals
  • Dry mouth reported occasionally

Drug & Supplement Interactions

  • SSRIs and MAOIs — risk of serotonin syndrome when combined with serotonergic drugs; contraindicated with MAOIs
  • 5-HTP — avoid combining; both raise serotonin and can cause serotonin excess
  • Sedative medications — additive drowsiness
  • Carbidopa — may enhance tryptophan's conversion to serotonin peripherally

Maximum Dose

Do not exceed: 6 g/day has been used in clinical research; doses above 3 g may cause GI upset and drowsiness

Full L-Tryptophan Guide

References

  1. (). Effects of tryptophan loading on human cognition, mood, and sleep. Neuroscience & Biobehavioral Reviews. DOI
  2. (). Tryptophan supplementation induces a positive bias in the processing of emotional material in healthy female volunteers. Psychopharmacology. DOI
  3. (). Effects of L-tryptophan on sleepiness and on sleep. Journal of Psychiatric Research. DOI