{"ok":true,"entry":{"slug":"5-htp","kind":"supplement","name":"5-htp","aliases":["5-hydroxytryptophan","oxitriptan","Griffonia simplicifolia"],"brands_sg":["California Gold Nutrition","NOW Foods","Nutricost","Swanson Vitamins","Thorne"],"class":"amino acid derivative","tags":["sleep","cognitive"],"use_for":"limited human evidence — sleep trials are small and old","use_after":null,"use_duration":"the singapore rct used 100 mg daily for 12 weeks","take_with":null,"pros":["sg 12-week rct: poor sleepers improved on the psqi","main natural source is griffonia simplicifolia seed","no definitive toxicity cases in ~20 years of use"],"cons":["sleep trials are small, old and often uncontrolled","nausea and vomiting reported at doses above 100 mg","peak x contaminants found in commercial 5-htp samples"],"dose_note":"the singapore rct gave 100 mg a day for 12 weeks to 30 older adults, single-blinded; the 2020 review reports dose-dependent gastrointestinal problems and vomiting and nausea at doses above 100 mg; no rda, ul or fda daily value exists, hsa's tables 4–5 cover vitamins and minerals only, and 5-htp is not named in hsa's oct 2025 prohibited/restricted annexes — l-tryptophan, a different substance, is in annex b for serotonergic interactions","dosage":{"ul":null,"unit":"mg","fda_dv":null,"rda_ai":null,"ul_status":"none_established","population":"general adult","hsa_max_daily":null},"ul_status":"none_established","sg_class":null,"cautions":["on ssris, maois or triptans — serotonin syndrome risk","on sedatives — hsa flags drowsiness for l-tryptophan","depression — sg bars disease claims on supplements","purity varies — contaminants found in otc samples"],"clashes":[{"src":["htp_review_serotonin","hsa_prohibited_tryptophan"],"note":"serotonin syndrome follows serotonergic hyperactivity; hsa's annex b flags the same risk for the precursor l-tryptophan","with":"serotonergic antidepressants (ssris, maois)"},{"src":["htp_review_carbidopa"],"note":"the 2020 review: this combination may cause psychopathological side effects such as acute anxiety","with":"carbidopa (peripheral decarboxylase inhibitor)"},{"src":["hsa_prohibited_tryptophan"],"note":"hsa annex b row is for l-tryptophan, not 5-htp: may cause drowsiness — carried as a near-neighbour flag","with":"sedatives (e.g. clonazepam, lorazepam)"}],"sources":[{"id":"htp_review_sleep","url":"https://europepmc.org/article/PMC/PMC7796270","label":"5-Hydroxytryptophan (5-HTP): Natural Occurrence, Analysis, Biosynthesis, Biotechnology, Physiology and Toxicology (Maffei, Int J Mol Sci 2021;22(1):181) — s8.2.3 Effect of 5-HTP on Sleep Disorders","quote":"In normal subjects treated with 5-HTP, rapid eye movement (REM) sleep increased from 5 to 53% of placebo baseline … the effects on sleep were associated with different doses of 5-HTP and the diverse possibilities of metabolic transformation","accessed":"2026-08-27"},{"id":"htp_review_serotonin","url":"https://europepmc.org/article/PMC/PMC7796270","label":"Maffei, Int J Mol Sci 2021 (same review) — s8.2.1 Serotonin Syndrome","quote":"Medication-induced serotonergic hyperactivity causes serotonin syndrome, which results from antidepressant medications and is characterized by the triad of altered mental status, autonomic dysfunction, and neuromuscular abnormalities … Excessive 5-HTP stimulation is the main pathophysiologic mechanism involved","accessed":"2026-08-27"},{"id":"htp_review_side_effects","url":"https://europepmc.org/article/PMC/PMC7796270","label":"Maffei, Int J Mol Sci 2021 (same review) — s8.2.2, dose-related side effects","quote":"… 5-HTP may cause dose-dependent gastrointestinal problems … vomiting and nausea have been reported when 5-HTP was used at doses above 100 mg","accessed":"2026-08-27"},{"id":"htp_review_carbidopa","url":"https://europepmc.org/article/PMC/PMC7796270","label":"Maffei, Int J Mol Sci 2021 (same review) — s8.2.2, combination with a peripheral decarboxylase inhibitor (carbidopa)","quote":"the combination of 5-HTP with a peripheral decarboxylase inhibitor may cause psychopathological side effects, like acute anxiety","accessed":"2026-08-27"},{"id":"htp_review_toxicology","url":"https://europepmc.org/article/PMC/PMC7796270","label":"Maffei, Int J Mol Sci 2021 (same review) — s9 toxicology / peak X contaminants","quote":"no definitive cases of toxicity have emerged despite the worldwide usage of 5-HTP for the last 20 years … samples of commercially available 5-HTP analyzed by HPLC-MS contained three or more contaminants of the peak X family","accessed":"2026-08-27"},{"id":"htp_review_source","url":"https://europepmc.org/article/PMC/PMC7796270","label":"Maffei, Int J Mol Sci 2021 (same review) — s10 Conclusions, natural source","quote":"The main natural source of 5-HTP is the seeds of the African plant Griffonia simplicifolia","accessed":"2026-08-27"},{"id":"htp_sg_rct","url":"https://europepmc.org/article/MED/38309227","label":"The impact of 5-hydroxytryptophan supplementation on sleep quality and gut microbiota composition in older adults: A randomized controlled trial (Clin Nutr 2024;43, doi 10.1016/j.clnu.2024.01.010; NCT04078724) — Singapore, n=30, single-blinded","quote":"Thirty older adults (66 ± 3 years) in Singapore were randomly assigned to either consume or not consume 100 mg 5-HTP daily … at week 12 … poor sleepers with 5-HTP supplementation were able to significantly improve subjective GSS","accessed":"2026-08-27"},{"id":"htp_depression_meta","url":"https://europepmc.org/article/MED/31504850","label":"Effects of 5-hydroxytryptophan on distinct types of depression: a systematic review and meta-analysis (Javelle et al., Nutr Rev 2020;78(1); PROSPERO CRD42018104415) — 13 studies reviewed, 7 meta-analysed","quote":"the OHAT (Office of Health Assessment and Translation risk of bias rating) tool suggested that, on the whole, current studies are relatively weak (few include placebo groups) … Methodological variability … contributes to heterogeneity in the results","accessed":"2026-08-27"},{"id":"hsa_prohibited_tryptophan","url":"https://file.go.gov.sg/hsa-chp-prohibited-restricted-ing-guidelines.pdf","label":"HSA Singapore — Guidelines on Prohibited and Restricted Ingredients in HS and TM, GL-CHPB-1-012 (October 2025), Annex B row 4 (L-tryptophan). 5-HTP itself is NOT listed in Annex A or Annex B","quote":"L-tryptophan — Known to interact with serotonergic antidepressants, e.g. SSRIs, MAOIs and might increase the risk of serotonergic side effects including serotonin syndrome … Known to interact with sedative medications, e.g. clonazepam, lorazepam","accessed":"2026-08-27"},{"id":"hsa_hs_guidelines","url":"https://file.go.gov.sg/hsa-hs-guidelines.pdf","label":"HSA Singapore — Health Supplements Guidelines (January 2026), s4.8 and Tables 4–5 (vitamins and minerals only)","quote":"4.8 HS for use by the general adult population should not contain vitamins and minerals exceeding the stipulated limits stated in Tables 4 and 5","accessed":"2026-08-27"},{"id":"hsa_hs_table6","url":"https://file.go.gov.sg/hsa-hs-guidelines.pdf","label":"HSA Singapore — Health Supplements Guidelines (January 2026), s6.6 and Table 6, prohibited claims (depression named under brain and nervous system)","quote":"HS must not be labelled, advertised or promoted for any specific medicinal purpose, i.e. treatment or prevention, implied or otherwise, of any disease or disorder … Brain and nervous system: Epilepsy … depression, eating disorders","accessed":"2026-08-27"},{"id":"iherb_sg","url":"https://sg.iherb.com/c/5-htp","label":"iHerb Singapore — 5-HTP category page, default (best-selling) order, SGD pricing","quote":"California Gold Nutrition, 5-HTP, 100 mg … NOW Foods, 5-HTP, 100 mg … Nutricost, 5-HTP, 200 mg … Swanson Vitamins, 5-HTP, 100 mg … Thorne, 5-Hydroxytryptophan, 90 Capsules","accessed":"2026-08-27"}],"brand_certs":[{"brand":"Thorne","example":null,"programme":"NSF Certified for Sport","matching_products":0,"brand_total_certified":66}],"updated_at":"2026-08-30T17:59:38.376296+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}