--- title: "5-HTP: Research & Side Effects | BodyHackGuide" url: https://www.bodyhackguide.co/compound/5-htp description: "5-HTP (5-hydroxytryptophan): mechanism, clinical studies & side effects." lang: en --- Skip to content Compare notes on r/BodyHackGuide (https://reddit.com/r/bodyhackguide) Compare notes with other researchers. Join r/BodyHackGuide (https://reddit.com/r/bodyhackguide) # 5-HTP (5-hydroxytryptophan) Supplement: https://www.bodyhackguide.co/wiki#cat-supplement Status Dietary supplement Evidence Not graded on a research bench yet 5-HTP (5-hydroxytryptophan) is an amino acid that the body makes from tryptophan on the way to serotonin and melatonin, and the L form sold in supplements has been extracted commercially from the seeds of the West African plant Griffonia simplicifolia. Reviewed 28 October 2026 01 Overview ## What 5-HTP (5-hydroxytryptophan) is 5-HTP is sold in the United States as a dietary supplement, and in Italy oxitriptan (L-5-HTP) is an authorized prescription medicine (PMID: 15068828, PMID: 28210931; Italian Medicines Agency database, checked 25 October 2026). Small trials have tested 5-HTP in depression, sleep terrors, appetite, fibromyalgia and headache, but a 2002 Cochrane review of 5-HTP and tryptophan found only two depression trials, with 64 patients, good enough to analyze (PMID: 11869656). 5-HTP has been studied for a possible link to eosinophilia-myalgia syndrome through contaminants, and for serotonin-related reactions when combined with other serotonergic drugs (PMID: 7699627, PMID: 12508395, PMID: 16023217). ### How it works ### Where 5-HTP sits in serotonin synthesis The body makes 5-HTP from the amino acid tryptophan with the enzyme tryptophan hydroxylase (TPH), which exists in two forms, TPH1 and TPH2 (PMID: 33375373). Removing a carboxyl group from 5-HTP (decarboxylation) gives serotonin (5-hydroxytryptamine), and serotonin can be converted further to melatonin (PMID: 33375373). The tryptophan-to-5-HTP step is the rate-limiting step in serotonin and melatonin synthesis, and 5-HTP taken by mouth enters the pathway after that step (PMID: 33375373). The form in supplements and in the prescription drug oxitriptan is the L form, L-5-hydroxytryptophan (PMID: 33375373). Read the full mechanism Show less ### Conversion outside the brain How much 5-HTP reaches the brain depends on how much is first converted to serotonin elsewhere in the body by the enzyme aromatic amino acid decarboxylase, and carbidopa, a peripheral decarboxylase inhibitor, blocks that conversion outside the brain (PMID: 16023217). In a crossover study of 12 healthy men, adding carbidopa to a 100 mg dose of 5-HTP doubled its elimination half-life and made total exposure (area under the curve) 15.4 times larger (PMID: 11910264). Studies in myoclonus and serotonin challenge tests have given 5-HTP together with carbidopa (PMID: 6966118, PMID: 18308795, PMID: 11910264). ### What 5-HTP changes in people - **Blood serotonin.** In a 166-patient trial in inflammatory bowel disease, serum 5-HTP and serotonin rose during 5-HTP treatment compared with placebo (PMID: 35940251). - **Stress hormones.** 5-HTP is used as a challenge test of serotonin function: in 15 healthy men given 5-HTP with carbidopa, cortisol and prolactin rose with dose (PMID: 18308795). - **Urine test for serotonin breakdown.** In 8 healthy adults, 10 days of 5-HTP raised urinary 5-hydroxyindoleacetic acid (5-HIAA), which is commonly measured to detect carcinoid tumors, to a median of 204 micromol a day against 18 on placebo (PMID: 18209781). ### Where 5-HTP comes from Seeds of the West African plant Griffonia simplicifolia contain 6 to 20 percent 5-HTP by wet weight (PMID: 33991640). Commercial 5-HTP has been produced by extraction from these seeds (PMID: 24936877). Wild West African populations are the sole commercial source of the seed, China is the main importer, and about 48 percent of the re-exported 5-HTP extracts go to North America (PMID: 33991640). ### Absorption and slow-release research Researchers at Duke University have argued that ordinary 5-HTP is absorbed and eliminated too quickly to work well as a drug, and have tested slow-release forms in mice (PMID: 27692695, PMID: 26932820). In mice given an SSRI antidepressant, ordinary 5-HTP injections caused brief serotonin spikes and marked adverse effects, while slow-release 5-HTP raised extracellular brain serotonin beyond the SSRI effect with no adverse effect observed (PMID: 26932820). A 2026 review, written with an author from the company Evecxia Therapeutics, notes that 5-HTP has poor drug properties and that no FDA-approved drug uses this approach to add to antidepressants (PMID: 41928689). ### Studied for - Depression - Serotonin biochemistry - Sleep - Appetite and obesity - Fibromyalgia - Headache - Cerebellar ataxia - Eosinophilia-myalgia syndrome ### Benefits listed - Hamilton depression scores similar to fluoxetine in a 70-patient trial without placebo (PMID: 23380314) - Depression scores in a 25-patient Parkinson's disease crossover trial (PMID: 32067288) - Panic response to a carbon dioxide challenge in 24 panic disorder patients (PMID: 12559480) - Sleep terror episodes in an open trial in 45 children (PMID: 15146330) Show 3 more Show less - Food intake and body weight in small trials in obese adults (PMID: 2468734, PMID: 1384305) - Fibromyalgia symptom measures in a 50-patient placebo-controlled trial (PMID: 2193835) - Ataxia scores in a 30-patient cerebellar ataxia trial (PMID: 3190503) 02 Research Free with email ## What the research shows No research bench grades 5-HTP (5-hydroxytryptophan) yet. Benches compare compounds people pair, with the evidence for each. ### Unlock the research summary Enter your email to keep reading. It is free, and it opens these sections on every compound page in this browser. - A summary of the key research - Safety and side effects - A link to the PubMed results You also get the free peptide cheat sheet by email. Unsubscribe anytime. Have an account? Sign in (https://www.bodyhackguide.co/auth) 03 Safety ## 5-HTP side effects and interactions ### Side effects #### Common - Nausea and vomiting rising with dose: dropout of 6.6 percent at 100 mg and 45.5 percent at 300 mg with carbidopa in healthy men (PMID: 18308795) - Fatigue, nausea or vomiting in 19.6 percent of the 5-HTP group after a single dose in a 112-adult trial (PMID: 42160304) - Gastrointestinal side effects tracking plasma 5-HTP levels (PMID: 6187038) #### Serious events - Eosinophilia-myalgia syndrome in one member of a family exposed to an impure 5-HTP batch, and high eosinophil counts in two others (PMID: 7699627) - Scleroderma-like illness during L-5-HTP and carbidopa treatment for myoclonus (PMID: 6997735) - Memory loss with MRI changes suggesting hippocampal ischemia after an accidental tenfold overdose, with recovery (PMID: 35878559) - Hypomania after starting 5-HTP with SAM-e (PMID: 29955516) - Serotonin syndrome-like poisoning in dogs, with 3 deaths among 21 cases (PMID: 10863592) ### Who should not use it Contraindications **Serotonergic antidepressants (SSRIs).** In healthy men, 5-HTP strengthened the hormonal response to the SSRI citalopram (PMID: 16378695), and in depressed patients the hormonal response to 5-HTP was larger in those taking fluoxetine than in those on tricyclic antidepressants or no medication (PMID: 9194044). In mice, ordinary 5-HTP given with an SSRI caused marked adverse effects (PMID: 26932820). A 2006 review of 5-HTP safety emphasized serotonin syndrome as well as EMS (PMID: 16023217). Read all the contraindications and cautions Show less **MAO inhibitors.** In mice, 5-HTP and the MAO inhibitor tranylcypromine each produced serotonin syndrome signs, and combinations of such serotonin-raising drugs increased them (PMID: 24780865). Mice lacking MAO enzymes reacted to 5-HTP with exaggerated serotonin syndrome behavior (PMID: 22964922). **Carbidopa.** Carbidopa multiplies 5-HTP exposure: in 12 healthy men it doubled the half-life and raised total exposure 15.4 times (PMID: 11910264). A scleroderma-like illness was reported with the L-5-HTP and carbidopa combination (PMID: 6997735). **Mood switching.** Hypomania was reported in a man taking 5-HTP with SAM-e for depression (PMID: 29955516). **Carcinoid tumor testing.** 5-HTP raises urinary 5-HIAA, which is commonly measured to detect carcinoid tumors, and the authors of that study advised ruling out over-the-counter 5-HTP as the cause of a raised 5-HIAA before tests for a carcinoid tumor begin (PMID: 18209781). **Product quality.** Contaminants of the peak X family have been found in commercial 5-HTP (PMID: 10721089, PMID: 12508395), and an EMS-related illness was reported with an impure batch (PMID: 7699627). **Pets.** 5-HTP supplements eaten by dogs have caused serotonin syndrome-like illness and deaths (PMID: 10863592, PMID: 28210931). **Pregnancy and breastfeeding.** No human safety data were found. ### Interactions 4 pairings in our record: 3 with a caution and 1 to monitor. - SSRIs and other serotonin reuptake inhibitors Caution 5-HTP strengthened the hormonal response to citalopram in healthy men (PMID: 16378695), and fluoxetine enlarged the hormonal response to 5-HTP in depressed patients (PMID: 9194044). In mice, ordinary 5-HTP given with an SSRI caused marked adverse effects (PMID: 26932820). - MAO inhibitors Caution In mice, 5-HTP and the MAO inhibitor tranylcypromine each produced serotonin syndrome signs, and combinations of such serotonin-raising drugs increased them (PMID: 24780865). Mice lacking MAO enzymes had exaggerated serotonin syndrome behavior after 5-HTP (PMID: 22964922). - SAM-e Caution A 42-year-old man developed hypomania about a week after starting 5-HTP together with SAM-e for depression (PMID: 29955516). - Carbidopa Monitor Carbidopa doubled the half-life of 5-HTP and raised its exposure 15.4 times in 12 healthy men (PMID: 11910264), and a scleroderma-like illness was reported with the combination (PMID: 6997735). This interaction data is compiled from published research and community reports. It may not be exhaustive. Always consult a healthcare professional before combining compounds. Need bloodwork before starting? Full hormone + metabolic panels from Anabolic Insights. Code CHONCH for first-order discount. Order Bloodwork (https://anabolicinsights.ai/?ref=nwm2zjb) 04 Dosing Free with email ## Dosing No dose on record Our record lists no dose for 5-HTP (5-hydroxytryptophan). This section holds what it does list. ### Unlock the Dosing section - Route 05 Prices ## 5-HTP (5-hydroxytryptophan) prices No listings We do not track a vendor for 5-HTP (5-hydroxytryptophan) yet, so this page states no price. 06 Chemistry ## Chemistry and structure Molecular formula C11H12N2O3 Molecular mass 220.22 g/mol CAS number 4350-09-8 Half-life About 2.2 to 7.4 hours in five healthy volunteers pretreated with carbidopa (PMID: 6187038), and about 6 hours after intravenous dosing in five carbidopa-pretreated patients (PMID: 311987). Carbidopa changes the kinetics: in 12 healthy men it doubled the elimination half-life of a 100 mg oral dose (PMID: 11910264). View on PubChem (https://pubchem.ncbi.nlm.nih.gov/compound/439280) 07 Related ## Related to 5-HTP (5-hydroxytryptophan) ### In the same category - Agmatine SulfatePhase 2/3 Agmatine sulfate is the sulfate salt of agmatine, a molecule made by removing a carboxyl group from the amino acid arginine, which is found in mammalian brain, in gut bacteria and in many foods.: https://www.bodyhackguide.co/compound/agmatine - GABA (gamma-aminobutyric acid)Phase 2 GABA (gamma-aminobutyric acid) is an amino acid that serves as the main inhibitory chemical messenger (neurotransmitter) in the brain; the body makes GABA from glutamate, and GABA is also found in foods such as green tea, tomatoes and fermented cheese.: https://www.bodyhackguide.co/compound/gaba - L-GlutaminePhase 3 L-glutamine is an amino acid the body makes for itself, which researchers call conditionally essential because the body's needs may outrun its own production during severe illness or stress.: https://www.bodyhackguide.co/compound/l-glutamine - ProbioticsDietary Supplement Probiotics — defined by the joint FAO/WHO 2001 consensus as "live microorganisms which, when administered in adequate amounts, confer a health benefit on the host" — are the most widely sold and most widely misunderstood category of dietary supplement.: https://www.bodyhackguide.co/compound/probiotics - SAM-e (S-adenosylmethionine)Phase 3 SAM-e (S-adenosylmethionine, also called ademetionine or AdoMet) is a molecule that mammalian cells make from the amino acid methionine and ATP, and it is the main donor of methyl groups for the body's methylation reactions.: https://www.bodyhackguide.co/compound/sam-e All compounds (https://www.bodyhackguide.co/wiki) ### Compare 5-HTP (5-hydroxytryptophan) - Alternatives to 5-HTP (5-hydroxytryptophan): https://www.bodyhackguide.co/alternatives-to/5-htp ### Research tools - Peptide Calculator Reconstitution and syringe units: https://www.bodyhackguide.co/tools/reconstitution - Reconstitution Guide How to mix, step by step: https://www.bodyhackguide.co/guides/how-to-reconstitute-peptides - Nasal Spray Calc mL per actuation: https://www.bodyhackguide.co/tools/intranasal - Half-Life Visualizer Decay curves: https://www.bodyhackguide.co/tools/halflife All articles (https://www.bodyhackguide.co/blog) 08 Questions ## Frequently asked questions What is 5-HTP? 5-HTP (5-hydroxytryptophan) is an amino acid that the body makes from tryptophan and then converts to serotonin and melatonin (PMID: 33375373). 5-HTP sold as a supplement is the L form, and commercial 5-HTP has been extracted from the seeds of the West African plant Griffonia simplicifolia (PMID: 33375373, PMID: 33991640, PMID: 24936877). Is 5-HTP a supplement or a prescription drug? 5-HTP is sold in the United States as a dietary supplement (PMID: 15068828). 5-HTP is not an FDA-approved drug: a Drugs@FDA search on 25 October 2026 found no application for oxitriptan or hydroxytryptophan. In Italy, 5-HTP is an authorized prescription medicine under the drug name oxitriptan, according to the Italian Medicines Agency database checked on 25 October 2026. Does 5-HTP help depression? The 2002 Cochrane review found 108 trials of 5-HTP or tryptophan for depression but only 2, with 64 patients, of good enough quality, and judged the evidence inconclusive (PMID: 11869656). A 2020 meta-analysis of 13 studies of 5-HTP in depression reported a pooled remission rate of 0.65 but rated the studies as weak because few had placebo groups (PMID: 31504850). In an Indian trial without placebo, 5-HTP and fluoxetine lowered depression scores by similar amounts (PMID: 23380314). Is 5-HTP linked to eosinophilia-myalgia syndrome? The 1989 eosinophilia-myalgia syndrome epidemic, with 1,531 US cases and 27 deaths reported by July 1990, was linked to manufactured L-tryptophan, the precursor of 5-HTP (PMID: 2398610, PMID: 33375373). A family exposed to an impure batch of 5-HTP included one member with eosinophilia-myalgia syndrome and two with high eosinophil counts (PMID: 7699627). Mayo Clinic chemists found peak X contaminants in commercial 5-HTP samples (PMID: 10721089, PMID: 12508395), while a 2004 review argued that no definitive case of 5-HTP toxicity had been shown (PMID: 15068828). Can 5-HTP cause serotonin syndrome? In mice, 5-HTP, fluoxetine and the MAO inhibitor tranylcypromine each produced serotonin syndrome signs, and combining these serotonin-raising drugs with one another increased the effects (PMID: 24780865). Dogs that accidentally ate 5-HTP supplements developed an illness resembling serotonin syndrome, and 3 of 21 dogs in one series died (PMID: 10863592). In people, 5-HTP strengthened the hormonal response to the SSRI citalopram (PMID: 16378695). In a 44-year-old man who took a tenfold 5-HTP overdose, doctors found no features of serotonin toxicity, although he developed memory loss (PMID: 35878559). What side effects has 5-HTP shown in trials? In a challenge study of 5-HTP given with carbidopa, nausea and vomiting were the most frequent side effects and rose with dose, causing 6.6 percent of healthy men to drop out at 100 mg and 45.5 percent at 300 mg (PMID: 18308795). After one dose of 5-HTP in a 112-adult trial, 19.6 percent of the participants given 5-HTP reported fatigue, nausea or vomiting (PMID: 42160304). 5-HTP also raises urinary 5-HIAA, which can give a false-positive result on a carcinoid tumor screening test (PMID: 18209781). What else has 5-HTP been tested for? Small 5-HTP trials have reported fewer sleep terrors in children, lower food intake and weight in obese adults, and improved fibromyalgia measures (PMID: 15146330, PMID: 1384305, PMID: 2193835). 5-HTP did not beat placebo for fatigue in a 166-patient inflammatory bowel disease trial or for menopausal hot flashes in 24 women (PMID: 35940251, PMID: 20031347). Free 2026 Peptide Cheat Sheet (PDF) 38 compounds and blends: vial sizes, BAC water volumes, dosing ranges and bloodwork markers. Download Free (https://www.bodyhackguide.co/guides/peptide-cheat-sheet-download) BodyHackGuide (https://www.bodyhackguide.co/) Your biohacking research hub: compound pricing, brain health protocols, dosing tools, and vendor reviews. support@bodyhackguide.co Join our Discord: https://discord.gg/Mhq5UdRYBA r/BodyHackGuide on Reddit: https://reddit.com/r/BodyHackGuide **Affiliate Disclosure:** We rank every vendor on the same public, reproducible methodology (https://www.bodyhackguide.co/vendors/methodology). Full details in our affiliate disclosure (https://www.bodyhackguide.co/affiliate-disclosure). **Research Disclaimer:** All compounds listed are for laboratory and research purposes only. Not for human consumption. This site does not sell or ship any products. Always consult a qualified healthcare professional and comply with local regulations. © 2026 BodyHackGuide. All rights reserved. - Terms: https://www.bodyhackguide.co/terms - Privacy: https://www.bodyhackguide.co/privacy ## Structured data ```json [ { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://www.bodyhackguide.co/" }, { "@type": "ListItem", "position": 2, "name": "Compounds", "item": "https://www.bodyhackguide.co/compare" }, { "@type": "ListItem", "position": 3, "name": "5-HTP (5-hydroxytryptophan)" } ] }, { "@context": "https://schema.org", "@type": "MedicalWebPage", "name": "5-HTP (5-hydroxytryptophan)", "description": "5-HTP (5-hydroxytryptophan) is an amino acid that the body makes from tryptophan on the way to serotonin and melatonin, and the L form sold in supplements has been extracted commercially from the seeds of the West African plant Griffonia simplicifolia (PMID: 33375373, PMID: 24936877, PMID: 33991640). 5-HTP is sold in the United States as a dietary supplement, and in Italy oxitriptan (L-5-HTP) is an authorized prescription medicine (PMID: 15068828, PMID: 28210931; Italian Medicines Agency database, checked 25 October 2026). Small trials have tested 5-HTP in depression, sleep terrors, appetite, fibromyalgia and headache, but a 2002 Cochrane review of 5-HTP and tryptophan found only two depression trials, with 64 patients, good enough to analyze (PMID: 11869656). 5-HTP has been studied for a possible link to eosinophilia-myalgia syndrome through contaminants, and for serotonin-related reactions when combined with other serotonergic drugs (PMID: 7699627, PMID: 12508395, PMID: 16023217).", "lastReviewed": "2026-10-28T15:35:05.236Z", "url": "https://www.bodyhackguide.co/compound/5-htp", "author": { "@type": "Person", "name": "BioChonch", "url": "https://www.bodyhackguide.co/about", "jobTitle": "Founder & Lead Researcher", "sameAs": [ "https://reddit.com/r/BodyHackGuide", "https://reddit.com/r/BrainHackGuide", "https://reddit.com/r/Biohackingher" ], "worksFor": { "@type": "Organization", "name": "BodyHackGuide", "url": "https://www.bodyhackguide.co" } }, "reviewedBy": { "@type": "Person", "name": "BioChonch", "url": "https://www.bodyhackguide.co/about", "jobTitle": "Founder & Lead Researcher", "sameAs": [ "https://reddit.com/r/BodyHackGuide", "https://reddit.com/r/BrainHackGuide", "https://reddit.com/r/Biohackingher" ], "worksFor": { "@type": "Organization", "name": "BodyHackGuide", "url": "https://www.bodyhackguide.co" } }, "publisher": { "@type": "Organization", "name": "BodyHackGuide", "url": "https://www.bodyhackguide.co" }, "mainContentOfPage": { "@type": "WebPageElement", "cssSelector": "main" }, "about": { "@type": "Drug", "name": "5-HTP (5-hydroxytryptophan)", "alternateName": [ "5-hydroxytryptophan", "5-hydroxy-L-tryptophan", "L-5-hydroxytryptophan", "L-5-HTP", "oxitriptan", "5-OHTrp", "Tript-OH", "Levothym", "Levotonine", "Cincofarm" ], "description": "5-HTP (5-hydroxytryptophan) is an amino acid that the body makes from tryptophan on the way to serotonin and melatonin, and the L form sold in supplements has been extracted commercially from the seeds of the West African plant Griffonia simplicifolia (PMID: 33375373, PMID: 24936877, PMID: 33991640). 5-HTP is sold in the United States as a dietary supplement, and in Italy oxitriptan (L-5-HTP) is an authorized prescription medicine (PMID: 15068828, PMID: 28210931; Italian Medicines Agency database, checked 25 October 2026). Small trials have tested 5-HTP in depression, sleep terrors, appetite, fibromyalgia and headache, but a 2002 Cochrane review of 5-HTP and tryptophan found only two depression trials, with 64 patients, good enough to analyze (PMID: 11869656). 5-HTP has been studied for a possible link to eosinophilia-myalgia syndrome through contaminants, and for serotonin-related reactions when combined with other serotonergic drugs (PMID: 7699627, PMID: 12508395, PMID: 16023217).", "activeIngredient": "5-HTP (5-hydroxytryptophan)", "administrationRoute": "Oral, Intravenous", "mechanismOfAction": "Where 5-HTP sits in serotonin synthesis The body makes 5-HTP from the amino acid tryptophan with the enzyme tryptophan hydroxylase (TPH), which exists in two forms, TPH1 and TPH2 (PMID: 33375373). Removing a carboxyl group from 5-HTP (decarboxylation) gives serotonin (5-hydroxytryptamine), and serotonin can be converted further to melatonin (PMID: 33375373). The tryptophan-to-5-HTP step is the rate-limiting step in serotonin and melatonin synthesis, and 5-HTP taken by mouth enters the pathway after that step (PMID: 33375373). The form in supplements and in the prescription drug oxitriptan is the L form, L-5-hydroxytryptophan (PMID: 33375373). Conversion outside the brain How much 5-HTP reaches the brain depends on how much is first converted to serotonin elsewhere in the body by the enzyme aromatic amino acid decarboxylase, and carbidopa, a peripheral decarboxylase inhibitor, blocks that conversion outside the brain (PMID: 16023217). In a crossover study of 12 healthy men, adding carbidopa to a 100 mg dose of 5-HTP doubled its elimination half-life and made total exposure (area under the curve) 15.4 times larger (PMID: 11910264). Studies in myoclonus and serotonin challenge tests have given 5-HTP together with carbidopa (PMID: 6966118, PMID: 18308795, PMID: 11910264). What 5-HTP changes in people Blood serotonin. In a 166-patient trial in inflammatory bowel disease, serum 5-HTP and serotonin rose during 5-HTP treatment compared with placebo (PMID: 35940251). Stress hormones. 5-HTP is used as a challenge test of serotonin function: in 15 healthy men given 5-HTP with carbidopa, cortisol and prolactin rose with dose (PMID: 18308795). Urine test for serotonin breakdown. In 8 healthy adults, 10 days of 5-HTP raised urinary 5-hydroxyindoleacetic acid (5-HIAA), which is commonly measured to detect carcinoid tumors, to a median of 204 micromol a day against 18 on placebo (PMID: 18209781). Where 5-HTP comes from Seeds of the West African plant Griffonia simplicifolia contain 6 to 20 percent 5-HTP by wet weight (PMID: 33991640). Commercial 5-HTP has been produced by extraction from these seeds (PMID: 24936877). Wild West African populations are the sole commercial source of the seed, China is the main importer, and about 48 percent of the re-exported 5-HTP extracts go to North America (PMID: 33991640). Absorption and slow-release research Researchers at Duke University have argued that ordinary 5-HTP is absorbed and eliminated too quickly to work well as a drug, and have tested slow-release forms in mice (PMID: 27692695, PMID: 26932820). In mice given an SSRI antidepressant, ordinary 5-HTP injections caused brief serotonin spikes and marked adverse effects, while slow-release 5-HTP raised extracellular brain serotonin beyond the SSRI effect with no adverse effect observed (PMID: 26932820). A 2026 review, written with an author from the company Evecxia Therapeutics, notes that 5-HTP has poor drug properties and that no FDA-approved drug uses this approach to add to antidepressants (PMID: 41928689).", "legalStatus": "Dietary supplement" } }, { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "What is 5-HTP?", "acceptedAnswer": { "@type": "Answer", "text": "5-HTP (5-hydroxytryptophan) is an amino acid that the body makes from tryptophan and then converts to serotonin and melatonin (PMID: 33375373). 5-HTP sold as a supplement is the L form, and commercial 5-HTP has been extracted from the seeds of the West African plant Griffonia simplicifolia (PMID: 33375373, PMID: 33991640, PMID: 24936877)." } }, { "@type": "Question", "name": "Is 5-HTP a supplement or a prescription drug?", "acceptedAnswer": { "@type": "Answer", "text": "5-HTP is sold in the United States as a dietary supplement (PMID: 15068828). 5-HTP is not an FDA-approved drug: a Drugs@FDA search on 25 October 2026 found no application for oxitriptan or hydroxytryptophan. In Italy, 5-HTP is an authorized prescription medicine under the drug name oxitriptan, according to the Italian Medicines Agency database checked on 25 October 2026." } }, { "@type": "Question", "name": "Does 5-HTP help depression?", "acceptedAnswer": { "@type": "Answer", "text": "The 2002 Cochrane review found 108 trials of 5-HTP or tryptophan for depression but only 2, with 64 patients, of good enough quality, and judged the evidence inconclusive (PMID: 11869656). A 2020 meta-analysis of 13 studies of 5-HTP in depression reported a pooled remission rate of 0.65 but rated the studies as weak because few had placebo groups (PMID: 31504850). In an Indian trial without placebo, 5-HTP and fluoxetine lowered depression scores by similar amounts (PMID: 23380314)." } }, { "@type": "Question", "name": "Is 5-HTP linked to eosinophilia-myalgia syndrome?", "acceptedAnswer": { "@type": "Answer", "text": "The 1989 eosinophilia-myalgia syndrome epidemic, with 1,531 US cases and 27 deaths reported by July 1990, was linked to manufactured L-tryptophan, the precursor of 5-HTP (PMID: 2398610, PMID: 33375373). A family exposed to an impure batch of 5-HTP included one member with eosinophilia-myalgia syndrome and two with high eosinophil counts (PMID: 7699627). Mayo Clinic chemists found peak X contaminants in commercial 5-HTP samples (PMID: 10721089, PMID: 12508395), while a 2004 review argued that no definitive case of 5-HTP toxicity had been shown (PMID: 15068828)." } }, { "@type": "Question", "name": "Can 5-HTP cause serotonin syndrome?", "acceptedAnswer": { "@type": "Answer", "text": "In mice, 5-HTP, fluoxetine and the MAO inhibitor tranylcypromine each produced serotonin syndrome signs, and combining these serotonin-raising drugs with one another increased the effects (PMID: 24780865). Dogs that accidentally ate 5-HTP supplements developed an illness resembling serotonin syndrome, and 3 of 21 dogs in one series died (PMID: 10863592). In people, 5-HTP strengthened the hormonal response to the SSRI citalopram (PMID: 16378695). In a 44-year-old man who took a tenfold 5-HTP overdose, doctors found no features of serotonin toxicity, although he developed memory loss (PMID: 35878559)." } }, { "@type": "Question", "name": "What side effects has 5-HTP shown in trials?", "acceptedAnswer": { "@type": "Answer", "text": "In a challenge study of 5-HTP given with carbidopa, nausea and vomiting were the most frequent side effects and rose with dose, causing 6.6 percent of healthy men to drop out at 100 mg and 45.5 percent at 300 mg (PMID: 18308795). After one dose of 5-HTP in a 112-adult trial, 19.6 percent of the participants given 5-HTP reported fatigue, nausea or vomiting (PMID: 42160304). 5-HTP also raises urinary 5-HIAA, which can give a false-positive result on a carcinoid tumor screening test (PMID: 18209781)." } }, { "@type": "Question", "name": "What else has 5-HTP been tested for?", "acceptedAnswer": { "@type": "Answer", "text": "Small 5-HTP trials have reported fewer sleep terrors in children, lower food intake and weight in obese adults, and improved fibromyalgia measures (PMID: 15146330, PMID: 1384305, PMID: 2193835). 5-HTP did not beat placebo for fatigue in a 166-patient inflammatory bowel disease trial or for menopausal hot flashes in 24 women (PMID: 35940251, PMID: 20031347)." } } ] }, { "@context": "https://schema.org", "@type": "Organization", "@id": "https://www.bodyhackguide.co#organization", "name": "BodyHackGuide", "alternateName": "BHG", "url": "https://www.bodyhackguide.co", "logo": { "@type": "ImageObject", "url": "https://www.bodyhackguide.co/logo.png", "width": 512, "height": 512 }, "description": "Evidence-based research reference for peptides and nootropics. 273 compound profiles, interactive dosing calculators, vendor price comparisons, and trust-scored vendor reviews scored on a public, reproducible methodology applied to every vendor. 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