NSTK · 01.2026Independent supplement reference
NutriStack
Edition 1.0Updated August 1, 2026

Supplement × Prescription·Evidence index

5-HTP and Fluoxetine: what the published research says

PubMed indexes 7 records that name 5-HTP and Fluoxetine together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.

Read this first

An evidence index, not guidance.

Every statement below is attributed to a named, dated, linked source.

This page lists published research relevant to 5-HTP and Fluoxetine. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.

The research

7 studies naming 5-HTP and Fluoxetine.

Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.

Comparative study of efficacy of l-5-hydroxytryptophan and fluoxetine in patients presenting with first depressive episode.

Asian journal of psychiatry · 2013 · PMID 23380314

Comparative StudyRandomized Controlled Trial70 participants

“l-5-HTP has definitely got antidepressant effect in patients of depression. Antidepressant effect was seen within 2weeks of treatment and was apparent in all degrees of depression. The therapeutic efficacy of l-5-HTP was considered as equal to that of fluoxetine.”

Jangid et al. · Authors' conclusion

Names both 5-HTP and Fluoxetine in its title.

Extracellular 5-hydroxytryptamine concentration in rat hypothalamus after administration of fluoxetine plus L-5-hydroxytryptophan.

The Journal of pharmacy and pharmacology · 1993 · PMID 7901377

Comparative StudyAnimal study

“doses, magnified the increase in extracellular 5-HT to as much as 16 times basal levels, although these doses of L-5-hydroxytryptophan alone had only small effects on extracellular 5-HT. The increased formation of 5-HT following L-5-hydroxytryptophan administration appears to overcome homeostatic mechanisms that limit the increases in extracellular 5-HT caused by uptake inhibition.”

Perry et al. · From the abstract

Names both 5-HTP and Fluoxetine in its title.

Blockade of pre- and post-synaptic 5-HT1A receptors does not modify the effect of fluoxetine or 5-hydroxytryptophan on ethanol and food intake in rats.

Psychopharmacology · 1997 · PMID 9399367

Animal study

“doses of (+)WAY100135 did not modify their inhibitory effect on ethanol and food consumption. Present findings suggest that blockade either of pre- or of pre- and postsynaptic 5-HT1A receptors does not potentiate the inhibitory effect of fluoxetine or 5-HTP on ethanol and food intake.”

Ciccocioppo et al. · From the abstract

Names both 5-HTP and Fluoxetine in its title.

5-Hydroxytryptophan as adjuvant therapy in treatment of moderate to severe obsessive-compulsive disorder: a double-blind randomized trial with placebo control.

International clinical psychopharmacology · 2020 · PMID 32541380

Randomized Controlled Trial

“5-Hydroxytryptophan augmentation therapy demonstrated higher partial and complete treatment response rate (P = 0.032 and P = 0.001, respectively) according to the Y-BOCS total scores. The results of this study confirm that 5-hydroxytryptophan may be effective as an augmentative agent in treatment of moderate-to-severe OCD.”

Yousefzadeh et al. · From the abstract

Names 5-HTP and Fluoxetine together in an interaction, co-administration, or pharmacokinetic context.

Limitations

What this evidence cannot tell you.

Search-based evidence indexes have real limits, and it is worth being explicit about them:

NutriStack

Track what you actually take.

NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers 5-HTP, Fluoxetine, and several hundred other substances.

The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.

NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.