NutriStack
5-HTP and Desvenlafaxine, contraindicated.
Desvenlafaxine blocks serotonin reuptake, while 5-HTP is converted directly into serotonin. Taking them together can push serotonin signaling into a toxic range and trigger serotonin syndrome, with agitation, tremor, sweating, diarrhea, clonus, fever, and confusion. Risk is higher with dose increases or any other serotonergic drug or substance.
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 Desvenlafaxine
- 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. Desvenlafaxine blocks serotonin reuptake, while 5-HTP is converted directly into serotonin. Taking them together can push serotonin signaling into a toxic range and trigger serotonin syndrome, with agitation, tremor, sweating, diarrhea, clonus, fever, and confusion. Risk is higher with dose increases or any other serotonergic drug or substance.
Mechanism. 5-HTP bypasses tryptophan hydroxylase and is decarboxylated by aromatic L-amino acid decarboxylase to serotonin. Desvenlafaxine inhibits SERT and NET, so increased serotonin synthesis is paired with reduced serotonin reuptake.
Recommendation. Do not take 5-HTP while using desvenlafaxine. Stop 5-HTP and discuss a washout plan before starting desvenlafaxine. Seek urgent care for fever, muscle rigidity, clonus, severe agitation, or confusion.
Sources (3)
- Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med. 2005;352(11):1112-1120. PMID 15784664
- Jacobsen JPR, Krystal AD, Krishnan KRR, Caron MG. Adjunctive 5-Hydroxytryptophan Slow-Release for Treatment-Resistant Depression: Clinical and Preclinical Rationale. Trends Pharmacol Sci. 2016;37(11):933-944. PMID 27692695
- Sansone RA, Sansone LA. Serotonin norepinephrine reuptake inhibitors: a pharmacological comparison. Innov Clin Neurosci. 2014;11(3-4):37-42. PMID 24800132
Stack Score
How this pair moves the number.
Effect on the composite score
If both 5-HTP and Desvenlafaxine 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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