What kind of interaction is it?

Contraindicated: the two should not be combined; the risk outweighs any benefit.

Is this interaction backed by published research?

Yes. NutriStack lists 2 citation rows for the L-Tryptophan + Trazodone pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Interaction databaseSupplement × PrescriptionReviewed May 2026

L-Tryptophan and Trazodone, contraindicated.

Q: Can I take L-Tryptophan and Trazodone together?

No. L-Tryptophan and Trazodone are contraindicated together. L-Tryptophan is the upstream serotonin precursor. Trazodone is a serotonin reuptake inhibitor and 5-HT2A antagonist with active metabolite mCPP that is itself a serotonin receptor agonist. Combined with supplemental tryptophan, synaptic serotonin can rise to toxic levels, with risk of serotonin syndrome (tremor, agitation, hyperthermia, clonus).

Q: How does this affect a NutriStack Stack Score?

-25 to your Stack Score per scored contraindication row.

L-Tryptophan is the upstream serotonin precursor. Trazodone is a serotonin reuptake inhibitor and 5-HT2A antagonist with active metabolite mCPP that is itself a serotonin receptor agonist. Combined with supplemental tryptophan, synaptic serotonin can rise to toxic levels, with risk of serotonin syndrome (tremor, agitation, hyperthermia, clonus).

2 primary source citations. Moderate evidence. Last verified May 30, 2026.

Open the interaction checker →Read the methodology

One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.

Sourcing standards·Evidence tiers

From the interaction database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.

At a glance

Substances: L-Tryptophan and Trazodone
Pair type: Contraindicated
Evidence (highest tier): Moderate
Source citations: 2 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. L-Tryptophan is the upstream serotonin precursor. Trazodone is a serotonin reuptake inhibitor and 5-HT2A antagonist with active metabolite mCPP that is itself a serotonin receptor agonist. Combined with supplemental tryptophan, synaptic serotonin can rise to toxic levels, with risk of serotonin syndrome (tremor, agitation, hyperthermia, clonus).

Mechanism. L-Tryptophan is decarboxylated to serotonin. Trazodone blocks SERT and its mCPP metabolite agonizes 5-HT receptors. Combined, supply and signal both rise, risking 5-HT receptor overstimulation.

Recommendation. Do not take L-tryptophan supplements with trazodone. Food sources of tryptophan are fine.

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both L-Tryptophan 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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