Clear evidence. Transparent sources. Practical guidance. Our evidence policyContact
Food Health Lab
Home › Supplements › Amino acids › Tryptophan / 5-HTP

Tryptophan & 5-HTP

The serotonin precursors — a real role in mood and sleep, but the SSRI caution is non-negotiable.

Reviewed by Bodil Isaksson, Licensed Biomedical Scientist (Sweden)Last reviewed July 2026Supplement guide

SupplementsAmino acidsMoodSleep

Tryptophan is the essential amino acid that becomes 5-HTP and then serotonin. Both are sold for mood, sleep and appetite — with one crucial safety rule.

Key takeaways

  • Pathway: tryptophan → 5-HTP → serotonin (and onward to melatonin).
  • 5-HTP is studied for mood, appetite and sleep, but doesn't clearly beat standard treatments.1
  • Do NOT combine with SSRIs, SNRIs or MAOIs — risk of serotonin syndrome.
  • Buy from reputable brands; discuss with a clinician if you take any antidepressant.

What they are

Tryptophan is an essential amino acid; the body converts it to 5-HTP and then serotonin, the neurotransmitter tied to mood, satiety and sleep. 5-HTP crosses into the brain more directly than tryptophan.

The evidence

5-HTP has been studied for low mood, appetite and sleep, with modest signals but no clear advantage over established treatments.1 The most important point is safety, not efficacy.

Dose & how to use

5-HTP studies use roughly 100–300 mg/day. Because of the serotonin-syndrome risk, this is not a casual stack-it-with-anything supplement.

Safety & who benefits

Never combine with serotonergic medication (SSRIs, SNRIs, MAOIs, triptans) without medical guidance. Avoid in pregnancy. Suitable only for carefully selected people, ideally with clinician input.

Bottom line: a real but modest serotonin support — and one where the SSRI/serotonin-syndrome caution matters far more than the benefit.

References

Adult research summary for education, not a prescription. These are food supplements, not treatments for disease.

  1. In Brief: 5-HTP for Depression. The Medical Letter, and reviews on 5-HTP/tryptophan safety. secure.medicalletter.org

This article summarises nutrition and exercise science for education. It is not a substitute for individual medical advice; consult a professional before starting a supplement, in pregnancy, or alongside medication.