{"ok":true,"entry":{"slug":"ornithine","kind":"supplement","name":"ornithine","aliases":["L-ornithine","ornithine alpha-ketoglutarate"],"brands_sg":["Swanson","NOW Foods","Nutricost","Source Naturals","Vitacost"],"class":"amino acid","tags":["sleep"],"use_for":"sleep quality and stress markers — two small rcts, mixed","use_after":"trials dosed daily, or 1 h before a stress test","use_duration":"trials dosed daily for weeks","take_with":null,"pros":["400 mg/day for 8 weeks cut the cortisol/dhea-s ratio","perceived sleep quality improved in that same rct","a 4-week study set a noael of 12 g/day in men"],"cons":["only two small rcts — 52 and 65 participants","a later rct found no effect on saliva cortisol","plasma aspartic and glutamic acid rose at the top dose"],"dose_note":"the two randomised trials read used 400 mg/day for 8 weeks and 1,600 mg/day for 7 days; a separate 4-week tolerance study set a no-observed-adverse-effect level of 12 g/day of ornithine hydrochloride in healthy men","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":["l-ornithine-l-aspartate is a prescription-only medicine in singapore (HEPA-MERZ infusion) — not the same product as an ornithine supplement","the trials read enrolled healthy adults only, and the 12 g/day tolerance study was in men"],"clashes":[],"sources":[{"id":"miyake2014","url":"https://europepmc.org/article/PMC/PMC4055948","label":"Randomised controlled trial of the effects of L-ornithine on stress markers and sleep quality in healthy workers (Miyake et al., Nutr J 2014; PMC4055948)","quote":"Fifty-two apparently healthy Japanese adults … were randomly divided into either the L-ornithine (400 mg/day) or placebo group … Serum cortisol levels and the cortisol/DHEA-S ratio were significantly decreased in the L-ornithine group","accessed":"2026-08-27"},{"id":"miyake2014_sleep","url":"https://europepmc.org/article/PMC/PMC4055948","label":"Miyake et al., Nutrition Journal 2014 — sleep and mood outcomes","quote":"Also, anger was reduced and perceived sleep quality was improved in the L-ornithine group.","accessed":"2026-08-27"},{"id":"moriyasu2024","url":"https://europepmc.org/article/PMC/PMC11676746","label":"Effects of Oral Ingestion of L-Ornithine on Mental Stress and Fatigue Based on the Trier Social Stress Test in Healthy Humans (Moriyasu et al., J Clin Med 2024; PMC11676746)","quote":"We randomly assigned 65 participants into two groups, ingesting orally either 1600 mg of L-ornithine or a placebo for 7 days … While L-ornithine did not affect saliva cortisol levels","accessed":"2026-08-27"},{"id":"moriyasu2024_fatigue","url":"https://europepmc.org/article/PMC/PMC11676746","label":"Moriyasu et al., J Clin Med 2024 — mood outcomes","quote":"it significantly improved the fatigue-inertia and anger-hostility scales of the Profile of Mood States on the morning after the TSST","accessed":"2026-08-27"},{"id":"miura2023","url":"https://europepmc.org/article/PMC/PMC9791970","label":"Subchronic tolerance trials of graded oral supplementation with ornithine hydrochloride or citrulline in healthy adults (Miura et al., Amino Acids 2023; PMC9791970)","quote":"A clinical, no-observed-adverse-effect-level (NOAEL) of ornithine hydrochloride and citrulline supplementation in healthy adult males was determined to be 12 g/day and 24 g/day (4 weeks), respectively.","accessed":"2026-08-27"},{"id":"miura2023_aa","url":"https://europepmc.org/article/PMC/PMC9791970","label":"Miura et al., Amino Acids 2023 — findings at the highest dosages","quote":"In the ornithine hydrochloride supplementation group, minor increase in plasma aspartic acid and glutamic acid concentrations was observed at the highest intake dosages.","accessed":"2026-08-27"},{"id":"hsa_register_lola","url":"https://data.gov.sg/datasets/d_767279312753558cbf19d48344577084/view","label":"HSA register of therapeutic products (data.gov.sg open data, 5,511 rows) — filtered locally 27 Aug 26 for ornithine","quote":"HEPA-MERZ INFUSION CONCENTRATE 5G/10 ML | L-Ornithine-L-Aspartate | Prescription Only","accessed":"2026-08-27"},{"id":"hsa_hs_defn","url":"https://file.go.gov.sg/hsa-hs-guidelines.pdf","label":"HSA Health Supplements Guidelines GL-CHPB-3-001 Rev. No. 020 (January 2026) — s3.1 working definition and clause 4.8 (Tables 4-5 cover vitamins and minerals only)","quote":"Vitamins, minerals, amino acids, fatty acids, enzymes, probiotics and other bioactive substances … 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_pr_notlisted","url":"https://file.go.gov.sg/hsa-chp-prohibited-restricted-ing-guidelines.pdf","label":"HSA Guidelines on Prohibited and Restricted Ingredients in HS and TM, GL-CHPB-1-012 Rev. No. 001 (Oct 2025), Annex A/B — full text searched 27 Aug 26, no row for ornithine","quote":"The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list.","accessed":"2026-08-27"},{"id":"iherb_sg","url":"https://sg.iherb.com/c/l-ornithine","label":"iHerb Singapore category page \"Ornithine\", default best-selling order, first 5 distinct brands","quote":"Ornithine","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:27.496708+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."}