{"ok":true,"entry":{"slug":"gaba","kind":"supplement","name":"gaba","aliases":["gamma-aminobutyric acid","PharmaGABA"],"brands_sg":["NOW Foods","Swanson Vitamins","Nutricost","Thorne","Natural Factors"],"class":"amino acid / neurotransmitter","tags":["sleep","cognitive"],"use_for":"limited evidence for stress, very limited for sleep","use_after":"review found no timing could be established","use_duration":null,"take_with":null,"pros":["14 placebo-controlled human trials reviewed in 2020","some sleep scores improved after a week or more of use","not listed in hsa's prohibited/restricted annexes"],"cons":["most single-dose trials showed no stress improvement","quality questioned — possible conflicts of interest","whether oral gaba reaches the brain is disputed"],"dose_note":"the 2020 systematic review of 14 placebo-controlled human trials says the precise dose for stress or sleep benefit “could not be established … neither in the current review nor in the general scientific literature”, and that the trials varied widely in dose, duration and measures; no rda, ul or fda daily value exists for gaba, hsa's tables 4–5 cover vitamins and minerals only, and gaba is not named in hsa's oct 2025 prohibited/restricted annexes","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":["long-term use — reviewed trials were short and small","no dose is established, so label amounts vary widely"],"clashes":[],"sources":[{"id":"gaba_review","url":"https://europepmc.org/article/PMC/PMC7527439","label":"Effects of Oral Gamma-Aminobutyric Acid (GABA) Administration on Stress and Sleep in Humans: A Systematic Review (Hepsomali et al., Front Neurosci 2020;14:923) — Abstract; 14 placebo-controlled trials, PRISMA","quote":"Fourteen studies met the criteria … more studies are needed before any inferences can be made about the efficacy of oral GABA consumption … there is limited evidence for stress and very limited evidence for sleep benefits","accessed":"2026-08-27"},{"id":"gaba_review_discussion","url":"https://europepmc.org/article/PMC/PMC7527439","label":"Hepsomali et al., Front Neurosci 2020 (same review) — Discussion, Summary of the Main Results","quote":"The majority of the studies did not find significant subjective improvements of stress scores after consuming a single dose … subjective sleep scores … improved only when there was a prolonged GABA use for at least 1 week","accessed":"2026-08-27"},{"id":"gaba_review_limits","url":"https://europepmc.org/article/PMC/PMC7527439","label":"Hepsomali et al., Front Neurosci 2020 (same review) — Limitations","quote":"the quality of many of the reviewed studies was questionable due to potential conflicts of interest, low participant numbers, and unequal control and intervention groups … the precise dose for efficiency … could not be established","accessed":"2026-08-27"},{"id":"gaba_review_bbb","url":"https://europepmc.org/article/PMC/PMC7527439","label":"Hepsomali et al., Front Neurosci 2020 (same review) — Introduction, blood–brain barrier permeability","quote":"GABA has long been thought to be unable to cross the blood–brain barrier (BBB) … which raises questions about the mechanisms of action behind its health benefits. However, there are various accounts regarding GABA's BBB permeability","accessed":"2026-08-27"},{"id":"hsa_prohibited_2025","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); GABA / gamma-aminobutyric acid not listed in Annex A or Annex B","quote":"Annex A: List of substances which are prohibited or restricted for use with conditions … Annex B: List of substances with potential safety issues … This list is not exhaustive. Dealers are responsible to ensure that their products are safe","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":"iherb_sg","url":"https://sg.iherb.com/c/gaba","label":"iHerb Singapore — GABA category page, default (best-selling) order, SGD pricing","quote":"NOW Foods, GABA, 100 Veg Capsules … Swanson Vitamins, Gaba, 250 mg … Nutricost, GABA, 750 mg … Thorne, PharmaGABA-100, 60 Capsules … Natural Factors, Stress-Relax®, Pharma GABA®, 60 Vegetarian 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."}