can you take 5-htp with an ssri or another antidepressant?

that is a prescriber question, not a shelf question. 5-htp is a direct serotonin precursor, and the risk of combining it with ssris, snris, maois, triptans, tramadol, linezolid or st john’s wort is serotonin syndrome. that risk is documented at the case-report level rather than in controlled trials, but the mechanism is real, and the tranylcypromine (maoi) label lists tryptophan, the parent compound, among the things not to combine with it. the signs are agitation or confusion, racing heart, sweating, fever, tremor and muscle jerking.

is 5-htp safe? what about the tryptophan recall?

the 1989 outbreak of eosinophilia-myalgia syndrome, 1,345 cases with deaths, was traced to contaminated l-tryptophan from a single manufacturer, not to 5-htp, which was never recalled. a trace contaminant called "peak x" has been reported in some 5-htp samples and a small number of similar cases have been described in 5-htp users; no outbreak has been established and the significance is disputed, and no regulator has settled it because no regulator tests supplements before sale. the common side effects are nausea, vomiting, diarrhoea and drowsiness.

is 5-htp fda approved?

no. it is sold as a dietary supplement under dshea, which means no fda review of safety, purity or effectiveness before sale, and it has never been approved to treat depression, anxiety, insomnia, fibromyalgia or anything else. the amount in a capsule is the manufacturer’s responsibility, not a regulator’s.

does 5-htp help with sleep or anxiety?

none of the studies on this page measured sleep. the one that measured anxiety, the 2025 trial of 100 mg a day in 30 older adults without depression, found no change in anxiety scores. the mechanism argument, that more serotonin means better sleep or less anxiety, is the same argument that makes it risky with antidepressants; it is not a trial result.

Supplement evidence

5-HTP

What the trials show, and the serotonergic interactions that make it a pharmacist question.

page first published 2026-09-08 · last updated 2026-10-06

Not an FDA-approved treatmentSold as a dietary supplement4 studies on this page

What Its Legal Status Actually Means

Read this before anything below it. Legal to sell is not the same fact as reviewed, verified, or approved.

5-HTP is sold in the US as a dietary supplement under DSHEA. It has never been approved by the FDA to treat depression, anxiety, insomnia, fibromyalgia, or anything else, and no FDA review of safety, purity, or effectiveness precedes it going on sale. Its close relative L-tryptophan was withdrawn from the US market in 1989-1990 after the eosinophilia-myalgia outbreak and later returned; 5-HTP, which is manufactured differently — usually extracted from the seed of the African plant Griffonia simplicifolia rather than produced by bacterial fermentation — was never part of that recall and has remained on sale throughout. Because it is a supplement, the amount of 5-HTP in a capsule and the presence of process contaminants are the manufacturer's responsibility, not a regulator's.

Quoted whole from the 2026-08-18 study harvest. Not summarized, not shortened.

does 5-htp work for depression? what the trials say

there is no fda label for 5-htp, because it is sold as a dietary supplement and has never been reviewed for effectiveness. the regulatory facts below come from the legal-status paragraph above, written from the regulator’s documents in the 2026-08-18 study harvest; every trial figure is from a study record on this page or a library row linked at the end. every source is linked at the end of this section. last checked 2026-10-06.

5-htp, 5-hydroxytryptophan, is the molecule the body makes from the amino acid tryptophan on the way to serotonin. it is sold in capsules, usually extracted from the seed of the african plant griffonia simplicifolia, for depression, anxiety and sleep. the whole usable human evidence for depression is two small trials from before 2002 and a handful of studies since, most with no placebo group. this section says what its legal status means, what the trials measured and in whom, what they found in both directions, and why the one interaction that matters is with antidepressants. every number is from a study record on this page or a library row, and each source is linked at the end.

this is information to take to a prescriber or pharmacist. nothing here tells anyone to take 5-htp or to stop, and nothing here is a reason to put off treatment that works.

what its legal status means, and does not mean

5-htp is sold in the united states as a dietary supplement under the 1994 dietary supplement health and education act. it has never been approved by the fda to treat depression, anxiety, insomnia, fibromyalgia or anything else, and no fda review of safety, purity or effectiveness precedes it going on sale [status]. legal to sell is not the same fact as reviewed, verified or approved. because it is a supplement, the amount in a capsule and the presence of manufacturing contaminants are the manufacturer’s responsibility, not a regulator’s [status].

one piece of history travels with it. its close relative l-tryptophan was withdrawn from the us market in 1989 to 1990 after an outbreak of eosinophilia-myalgia syndrome, 1,345 cases meeting the cdc’s surveillance definition, with deaths, that case-control studies traced to contaminated product from a single japanese manufacturer; it later returned to sale. 5-htp, made differently, was never part of that recall and has stayed on sale throughout [status; risks]. the related but distinct concern is a trace contaminant nicknamed "peak x" reported in some 5-htp samples, with a small number of similar cases described in 5-htp users; no outbreak has been established, the significance of the contaminant is disputed, and no regulator has settled the dispute, because no regulator tests these products before sale [risks]. the one published safety review arguing the concern lacks credibility was written from a supplement-industry laboratory, which is why it informs the risks paragraph but is not a study record here [exclusions].

what the trials measured, in whom, and for how long

the only cochrane review of 5-htp and tryptophan for depression, from 2002, located 108 trials and found two of sufficient quality to include, with 64 patients between them [shaw-2002]. it has not been updated in more than two decades, and the harvest notes that almost nothing usable has been published since [exclusions]. a 2020 systematic review found 13 studies and pooled seven, most without a placebo group, and the authors’ own risk-of-bias assessment rated them relatively weak [javelle-2020]. the one trial against an antidepressant randomised 70 people in india in a first depressive episode to 5-htp or fluoxetine for eight weeks; 60 finished, and there was no placebo arm [jangid-2013]. the newest randomised trial, from 2025, gave 100 mg a day or no supplement for 12 weeks to 30 singaporean adults averaging 66 years old; it was single-blinded, had no placebo capsule, and enrolled people whose depression score averaged 1.2 on a 15-point scale, which is to say people with essentially no depression to treat [li-2025].

so the question "does 5-htp work for depression" has been asked of about 64 people under placebo control, ever, and of a few hundred more in studies that could not tell the supplement from time and expectation. no trial on this page measured sleep, and the 2025 trial found no change in anxiety scores [li-2025].

what the research says, in both directions

in favour. the two trials cochrane accepted favoured 5-htp or tryptophan over placebo, with a pooled odds ratio of 4.10 [shaw-2002]. the 2020 pooling reported a remission rate of 65% and a large effect on questionnaire scores (hedges’ g 1.11) [javelle-2020]. in the indian trial, both groups improved from week two onward with no meaningful difference, 73.3% responding on 5-htp against 80% on fluoxetine, and the authors called the two comparable [jangid-2013]. the 2025 trial reported a fall in geriatric depression score from 1.2 to 0.7 and a one-point rise on a cognitive screen, with serum serotonin rising [li-2025].

against, or smaller than it sounds. the cochrane odds ratio rests on 64 patients and a confidence interval running from 1.28 to 13.15, which the reviewers called insufficient to be conclusive; they concluded that because antidepressants proven effective already exist, the clinical usefulness of 5-htp and tryptophan is limited [shaw-2002]. a 65% remission rate from studies without placebo groups measures how many people improved, not how many improved because of 5-htp; depression remits substantially on placebo and with time, and the heterogeneity between studies was high (i-squared 76%) [javelle-2020]. a trial in which both arms improve and neither wins cannot distinguish "both work" from "neither works and people recovered anyway", and 60 completers is far too few to establish equivalence; it has not been replicated [jangid-2013]. a half-point change on a scale where the group started at 1.2 is not interpretable as treating depression, and the authors themselves called the results preliminary [li-2025].

the interaction that matters, and the side effects

5-htp is a direct serotonin precursor, so the interaction that matters is with other drugs that raise serotonin: ssris, snris, maois, triptans, tramadol, linezolid and st john’s wort. serotonin syndrome from 5-htp is a theoretical and case-report-level concern rather than something demonstrated in controlled trials, but the mechanism is real and it is the single best reason to tell a prescriber before combining [risks]. the clearest regulator statement is on an maoi label: the tranylcypromine prescribing information lists tryptophan, the parent compound, among the products not to be combined with the drug because of the risk of serotonin syndrome or a blood-pressure crisis [maoi-label]. the commonly reported side effects are nausea, vomiting, diarrhoea and drowsiness [risks].

one more fact about dose. the trials on this page used different amounts, the 2025 trial 100 mg a day, and no regulator has set a dose, verified a capsule’s content, or tested a product for the contaminant described above [status; risks]. whatever the trials found applies to the product and dose they used, not to a bottle on a shelf.

questions for a prescriber or pharmacist about 5-htp

each one comes from a warning or a study above. they are questions, not instructions; the answers depend on a history nobody here has.

i take, or have recently stopped, an antidepressant, a triptan, tramadol or st john’s wort. 5-htp adds serotonin to all of these; is that combination safe for me, and what are the signs of serotonin syndrome?
the only placebo-controlled evidence is two trials in 64 people. if i am considering this instead of a treatment with trials in thousands, what am i weighing?
the newest trial was in people without depression and had no placebo. is there anything in it that applies to someone who does have depression?
no regulator checks what is in a 5-htp capsule or tests it for the "peak x" contaminant. does that change which product, if any, you would be comfortable with me taking?
if i am taking this for sleep or anxiety: no trial on this page measured sleep, and the one that measured anxiety found no change. what is the plan if it does not help?
if my mood does not improve in the eight to twelve weeks these trials ran, what happens next?

questions people ask

does 5-htp work for depression?: not shown. the only cochrane review, from 2002, found two usable trials in 64 people, which favoured 5-htp or tryptophan over placebo but with a confidence interval too wide to conclude anything; the reviewers judged its clinical usefulness limited given that proven antidepressants exist. later studies mostly had no placebo group, so a 65% remission rate in one pooling measures improvement, not improvement caused by 5-htp. the one trial against an antidepressant had 60 completers and no placebo arm, and the newest trial, in 2025, had 30 people who were not depressed and no placebo pill.
can you take 5-htp with an ssri or another antidepressant?: that is a prescriber question, not a shelf question. 5-htp is a direct serotonin precursor, and the risk of combining it with ssris, snris, maois, triptans, tramadol, linezolid or st john’s wort is serotonin syndrome. that risk is documented at the case-report level rather than in controlled trials, but the mechanism is real, and the tranylcypromine (maoi) label lists tryptophan, the parent compound, among the things not to combine with it. the signs are agitation or confusion, racing heart, sweating, fever, tremor and muscle jerking.
is 5-htp safe? what about the tryptophan recall?: the 1989 outbreak of eosinophilia-myalgia syndrome, 1,345 cases with deaths, was traced to contaminated l-tryptophan from a single manufacturer, not to 5-htp, which was never recalled. a trace contaminant called "peak x" has been reported in some 5-htp samples and a small number of similar cases have been described in 5-htp users; no outbreak has been established and the significance is disputed, and no regulator has settled it because no regulator tests supplements before sale. the common side effects are nausea, vomiting, diarrhoea and drowsiness.
is 5-htp fda approved?: no. it is sold as a dietary supplement under dshea, which means no fda review of safety, purity or effectiveness before sale, and it has never been approved to treat depression, anxiety, insomnia, fibromyalgia or anything else. the amount in a capsule is the manufacturer’s responsibility, not a regulator’s.
does 5-htp help with sleep or anxiety?: none of the studies on this page measured sleep. the one that measured anxiety, the 2025 trial of 100 mg a day in 30 older adults without depression, found no change in anxiety scores. the mechanism argument, that more serotonin means better sleep or less anxiety, is the same argument that makes it risky with antidepressants; it is not a trial result.

sources for this section

the library rows link to our one-page summary of each study, with the original paper, its funding and our evidence grade on that page.

What the Research Shows

4 records from the 2026-08-18 harvest, each checked against PubMed and Europe PMC on that date. How a study was designed, how many people were in it, and who paid for it are printed above what it found, because those three facts decide how much the finding is worth.

Study 1 · 2002
- Systematic review of randomized trials
- 64 participants
- Top-tier journal
- Funding not established
moderate69/100
Reasonable evidence with real limitations.
Read this first: The pooled odds ratio looks impressive but rests on 64 patients with a confidence interval running from 1.28 to 13.15 — statistically positive and practically uninformative. The review is from 2002 and predates almost nothing, because almost nothing usable has been published since.
The reviewers located 108 trials of tryptophan or 5-HTP for depression and found that only two of them, involving 64 patients in total, were of sufficient quality to include. Those two favoured the supplements over placebo (Peto odds ratio 4.10, 95% CI 1.28 to 13.15), but the reviewers judged the evidence insufficient to be conclusive and concluded that, because antidepressants proven effective and safe already exist, the clinical usefulness of 5-HTP and tryptophan is limited. This remains the only Cochrane review of 5-HTP for depression and has not been updated in over two decades.
Shaw K, Turner J, Del Mar C. (2002). Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database of Systematic Reviews. PMID 11869656.
How this record was checked
PubMed record 11869656 fetched via NCBI efetch 2026-08-18; title, authors, journal (Cochrane Database Syst Rev 2002;(1):CD003198), year, DOI, and the exact figures — 108 trials located, 2 included, 64 patients, Peto OR 4.10 (95% CI 1.28-13.15) — confirmed from the abstract. Europe PMC core record checked 2026-08-18: no grant list and no funding statement available, and the Cochrane Library page was not read, so funding is recorded UNKNOWN and conflicts false. A PubMed search on CD003198 returned no later version, so this 2002 review is the current one.
Study 2 · 2020
- Systematic review of observational studies
- Reputable journal
- Funding not established
- Preregistered
moderate63/100
Reasonable evidence with real limitations.
Read this first: A pooled remission rate from mostly uncontrolled trials measures how many people improved, not how many improved because of 5-HTP; depression remits substantially on placebo and with time. Classified here as a systematic review of largely non-randomised evidence rather than a meta-analysis of RCTs for exactly that reason.
Thirteen studies entered the systematic review and seven the meta-analysis, yielding a pooled depression remission rate of 0.65 (95% CI 0.55 to 0.78) and a large effect on questionnaire scores (Hedges' g 1.11, 95% CI 0.53 to 1.69) with substantial heterogeneity (I-squared 76%). The authors' own risk-of-bias assessment rated the underlying studies as relatively weak, noting that few included placebo groups — which is why a 65% remission rate here is not comparable to a placebo-controlled remission rate, and why they call for placebo-controlled trials in well-defined patients.
Javelle F, Lampit A, Bloch W, Häussermann P, Johnson SL, Zimmer P. (2020). Effects of 5-hydroxytryptophan on distinct types of depression: a systematic review and meta-analysis. Nutrition Reviews. PMID 31504850.
How this record was checked
PubMed record 31504850 fetched via NCBI efetch 2026-08-18; title, all six authors, journal (Nutr Rev 2020;78(1):77-88), year, DOI, the 13-study/7-study split, remission rate 0.65 (95% CI 0.55-0.78), Hedges' g 1.11, and the PROSPERO registration CRD42018104415 (hence preregistered true) all confirmed from the abstract. Europe PMC core record checked 2026-08-18: no PMC full text, no grant list, no funding statement, so funding is recorded UNKNOWN and conflicts false. Total participant N is not stated in the record, so sampleSize is left null rather than guessed.
Study 3 · 2013
- Randomized trial
- 60 participants
- Reputable journal
- Funding not established
moderate57/100
Reasonable evidence with real limitations.
Read this first: No placebo arm and no power calculation for equivalence: a trial in which both arms improve and neither wins cannot distinguish "both work" from "neither works and people recovered anyway", and 60 completers is far too few to establish non-inferiority. A single-centre trial that has not been replicated.
Seventy Indian patients in a first depressive episode were randomised to L-5-HTP or fluoxetine for eight weeks; 60 completed. Both groups improved on the Hamilton Depression Rating Scale from week two onward with no meaningful difference between them — 73.3% responded on 5-HTP versus 80% on fluoxetine — and the authors concluded the two were comparable. There was no placebo arm, so the trial shows only that the two treatments moved together, not that either beat the natural course of a first episode.
Jangid P, Malik P, Singh P, Sharma M, Gulia AK. (2013). Comparative study of efficacy of l-5-hydroxytryptophan and fluoxetine in patients presenting with first depressive episode. Asian Journal of Psychiatry. PMID 23380314.
How this record was checked
PubMed record 23380314 fetched via NCBI efetch 2026-08-18; title, all five authors, journal (Asian J Psychiatr 2013;6(1):29-34), year, DOI, and the numbers — 70 recruited, 60 completed and randomised into two arms, 8 weeks, 73.33% versus 80% response — confirmed from the abstract. Europe PMC core record checked 2026-08-18: no PMC full text, no grant list, no funding statement, so funding is UNKNOWN, conflicts false, and independence left null (unchecked) rather than asserted.
Study 4 · 2025
- Randomized trial
- 30 participants
- Indexed journal
- Independently funded
- Preregistered
- Declared conflicts of interest
strong80/100
Well-supported by good-quality research.
Read this first: The rubric score overstates this trial badly. It was single-blinded with a no-supplement control rather than a placebo capsule, so expectancy is uncontrolled; it enrolled 30 people; and the mood change it reports is half a point on a scale where the group started at 1.2 out of 15, which is not clinically interpretable as treating depression. It is included as the most recent randomised 5-HTP evidence that exists, which is itself the point: this is what "current evidence" looks like for 5-HTP.
Thirty Singaporean adults averaging 66 years old were randomised to 100 mg/day of 5-HTP or to no supplement for 12 weeks. The 5-HTP group's Montreal Cognitive Assessment score rose about one point (26.6 to 27.6) and its Geriatric Depression Scale score fell from 1.2 to 0.7, with serum serotonin rising; anxiety scores and the other blood biomarkers did not change. The authors themselves flag the small sample and short duration and call the results preliminary — and the baseline depression score of 1.2 on a 15-point scale means these were people with essentially no depression to treat.
Li S, Sutanto CN, Xia X, Kim JE. (2025). The Impact of 5-Hydroxytryptophan Supplementation on Cognitive Function and Mood in Singapore Older Adults: A Randomized Controlled Trial. Nutrients. PMID 40944161.
How this record was checked
PubMed record 40944161 fetched via NCBI efetch 2026-08-18; title, all four authors, journal (Nutrients 2025;17(17):2773), year, DOI, N=30, the 100 mg/day dose, the 12-week design, and the MoCA and GDS figures confirmed from the abstract, which also carries "The authors declare no conflict of interest" (hence conflicts true). Europe PMC core record fetched 2026-08-18 lists National University of Singapore iHealthtech grants R-160-000-A89-133 and R-160-000-A89-733, hence funding INDEPENDENT. PMC full text PMC12430700 read 2026-08-18 confirms registration at ClinicalTrials.gov as NCT04078724, hence preregistered true, and confirms the single-blind, no-supplement-control design.

The Risks

Nobody checks this purchase the way a prescription is checked. No prescriber reviews it against the rest of what you take, no pharmacist screens the interaction, and no regulator confirms the dose in the capsule before it is sold. That is why this section sits here at full length rather than as a footnote.

What the paragraph below covers:

Serotonin syndrome
Drug interactions
What is actually in the product
Stomach and gut
Sedation

5-HTP is a direct serotonin precursor, so the interaction that matters is with other serotonergic drugs: SSRIs, SNRIs, MAOIs, triptans, tramadol, linezolid, and St John's wort. Serotonin syndrome from 5-HTP is a theoretical and case-report-level concern rather than something demonstrated in controlled trials, but the mechanism is real and it is the single best reason to tell a prescriber before combining. The commonly reported side effects are nausea, vomiting, diarrhoea, and drowsiness. On the eosinophilia-myalgia question, the accurate version is this: the 1989 outbreak — 1,345 cases meeting the CDC surveillance case definition, with deaths — was traced to contaminated L-tryptophan produced by a single Japanese manufacturer, Showa Denko, and case-control studies found illness essentially confined to that manufacturer's product. It was not a 5-HTP outbreak. The related but distinct concern is that a trace contaminant nicknamed "peak X" has been reported in some 5-HTP samples and a small number of EMS-like cases have been described in 5-HTP users; no outbreak has ever been established, the analytical significance of peak X is disputed, and the dispute has never been settled by a regulator, because no regulator tests these products before sale.

What Is Not Known

The boundaries of the section above, in the harvest’s own words. What it excluded, why, and where it looked and found nothing. An absence of evidence is not evidence of absence, and it is not evidence of benefit either.

What Was Left Out, and Why

Quoted from the harvest, where these notes sat above the study list rather than after it. Where a note says “below” it means the studies in the section above.

Das 2004 "Safety of 5-hydroxy-L-tryptophan" (Toxicol Lett, PMID 15068828) was fetched and verified but is excluded as a study record: it is a narrative safety review written from a supplement-industry laboratory (ISSI Laboratories Inc.) arguing that the "peak X" contaminant concern lacks credibility. It informed the known_risks wording only, and is flagged here so the reader knows a pro-supplement safety review exists and who wrote it.
The 1989 eosinophilia-myalgia epidemiology (Kilbourne 1996 PMID 8895184; Sullivan 1996 PMID 8895159, 1,345 CDC-surveillance cases) was fetched to fix the facts in known_risks but concerns L-tryptophan, not 5-HTP, so it is not listed as a 5-HTP efficacy study.
Pre-1990 open-label 5-HTP series are excluded; the Shaw Cochrane review rejected 106 of 108 located trials on quality grounds, and repeating them here would inflate the record.

The Retraction Check

PubMed efetch records for all four PMIDs inspected 2026-08-18 for "Retraction in" flags; none present, and no errata or expressions of concern.

Questions for a Prescriber or Pharmacist

This page does not tell anyone to take 5-HTP or to avoid it. It is not able to: it does not know what else you take, what you have tried, or what you are treating. These are the questions each study above raises, written to be asked out loud.

Only two usable trials of 5-HTP for depression exist and they enrolled 64 people between them — is there any reason to bet on that instead of a treatment that has been tested in thousands?
Most of the 5-HTP studies had no placebo group, so people got better but nobody knows against what — does that change how much weight we should put on the numbers?
The one trial comparing 5-HTP to an antidepressant had 60 people finish and no placebo group — is that enough for you to consider it a real alternative to an SSRI?
The newest 5-HTP trial had 30 people, no placebo pill, and participants who weren't depressed to begin with — does anything in it apply to someone who actually has depression?

And the one to ask at the counter, whatever the answers above turn out to be: given everything I am already taking, what would you want to know about 5-HTP before I put it in the same body?

Open 5-HTP in veisund

The app has the resources behind this page and people working through the same questions.What you post there goes to people, not to a model. If someone answers, it is a person who has been there. The one automated message is a crisis-resource reply.

Where This Page Comes From

Transcribed from the study-harvest-2026-08-18 record for 5-htp, built into this page by scripts/supplement-ingest.mjs on 2026-09-07. Nothing here is fetched at page load, and nothing here was written by a model without a citation behind it.

Source file	study-harvest/2026-08-18/5-htp.yaml
Source repo	REPTechnologies/avalo-backend
SHA-256	00a378407387783000583e84ad975d34edd2f3a374c2474fb6207e6ecb8a7ccf
Also searched as	5-HTP, 5-hydroxytryptophan, L-5-HTP, oxitriptan, Griffonia simplicifolia extract

The Other Substances

Do any supplements actually work? asks the question across all of them. The full library has the medication records, the funding investigations, and the glossary.