Interaction databaseSupplement × PrescriptionReviewed May 2026

5-HTP and Trazodone, contraindicated.

Trazodone is a serotonin antagonist and reuptake inhibitor (SARI). Combined with 5-HTP, the increased serotonin production creates serotonin syndrome risk.

One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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At a glance

Substances
5-HTP and Trazodone
Pair type
Contraindicated
Evidence (highest tier)
Moderate
Source citations
3 sources
Stack Score effect
−25 to your Stack Score (per scored contraindication row).
Scope
Supplement × Prescription
Last verified
May 30, 2026

Contraindicated · Moderate evidence

Contraindicated

What is happening. Trazodone is a serotonin antagonist and reuptake inhibitor (SARI). Combined with 5-HTP, the increased serotonin production creates serotonin syndrome risk.

Mechanism. Trazodone blocks SERT and antagonizes 5-HT2A receptors. While the 5-HT2A antagonism might seem protective, SERT blockade combined with 5-HTP-derived serotonin excess still poses serotonin syndrome risk.

Recommendation. Do NOT take 5-HTP with trazodone. If additional sleep support is needed, discuss non-serotonergic options with your prescriber.

Sources (3)
  1. Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med. 2005;352(11):1112-1120. PMID 15784664
  2. Truyens M, Lobatón T, Ferrante M et al.. Effect of 5-Hydroxytryptophan on Fatigue in Quiescent Inflammatory Bowel Disease: A Randomized Controlled Trial. Gastroenterology. 2022. PMID 35940251
  3. Sutanto CN, Xia X, Heng CW et al.. The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial. Clinical Nutrition. 2024. PMID 38309227

Stack Score

How this pair moves the number.

Effect on the composite score

If both 5-HTP and Trazodone are in the same stack, this pair applies −25 to your Stack Score (per scored contraindication row).

The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.

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