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GABA

Supplement amino acid / neurotransmitter sleepbrain & mood
Aka: gamma-aminobutyric acid, PharmaGABA
Brands seen in Singapore: NOW Foods, Swanson Vitamins, Nutricost, Thorne, Natural Factors
Third-party tested: Thorne certifies other products with NSF Certified for Sport, but nothing for gaba.Certification is granted per product, so check the tub you actually own. Not being listed is not the same as failing.
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Limited evidence for stress, very limited for sleep
When to take
Review found no timing could be established
Pros & cons
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
Sources
  1. 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 · read 2026-08-27
    what it says
    “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”
  2. Hepsomali et al., Front Neurosci 2020 (same review) — Discussion, Summary of the Main Results · read 2026-08-27
    what it says
    “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”
  3. Hepsomali et al., Front Neurosci 2020 (same review) — Limitations · read 2026-08-27
    what it says
    “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”
  4. Hepsomali et al., Front Neurosci 2020 (same review) — Introduction, blood–brain barrier permeability · read 2026-08-27
    what it says
    “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”
  5. 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 · read 2026-08-27
    what it says
    “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”
  6. HSA Singapore — Health Supplements Guidelines (January 2026), s4.8 and Tables 4–5 (vitamins and minerals only) · read 2026-08-27
    what it says
    “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”
  7. iHerb Singapore — GABA category page, default (best-selling) order, SGD pricing · read 2026-08-27
    what it says
    “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”
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Updated 2026-08-30. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.