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Gymnema

Supplement botanical general nutrition
Aka: Gymnema sylvestre, gurmar
Brands seen in Singapore: Swanson Vitamins, NOW Foods, Source Naturals, Himalaya, Vitacost
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
Blunts sweet taste; blood-sugar effect is not settled
Pros & cons
Pros
  • Gymnemic acids blunt the taste of sweet things
  • Meta-analysis of 10 trials: fasting glucose fell
  • Side effects at usual doses are uncommon
Cons
  • Livertox: effectiveness in diabetes not shown
  • That meta-analysis compared to baseline, not placebo
  • Rare liver-injury reports; long-term safety unclear
Sources
  1. NIH NIDDK LiverTox — Gymnema sylvestre, Background · read 2026-08-27
    what it says
    “In vitro, gymnemic acids have been shown to bind to and inhibit human, sweet taste receptors, and both animal and human studies indicate the ingredients can suppress taste response to sweet substances.”
  2. NIH NIDDK LiverTox — Gymnema sylvestre, human trial results · read 2026-08-27
    what it says
    “Several trials of Gymnema extracts in humans have shown mild decreases in fasting plasma glucose levels accompanied by increases in hemoglobin A1c levels, but the overall effectiveness in the treatment of diabetes has not been shown”
  3. NIH NIDDK LiverTox — Gymnema sylvestre, doses and product standardisation · read 2026-08-27
    what it says
    “The typical recommended dose is 400 mg three times daily, but some commercial products recommend as much as several grams daily. At present there is little standardization of purity and concentration of extracts in Gymnema products.”
  4. NIH NIDDK LiverTox — Gymnema sylvestre, side effects · read 2026-08-27
    what it says
    “Side effects of conventional doses are uncommon but may include nausea, abdominal discomfort, diarrhea, headaches, and rash. Its long term safety has not been well documented in humans.”
  5. NIH NIDDK LiverTox — Gymnema sylvestre, likelihood score and risk factors · read 2026-08-27
    what it says
    “Likelihood score : D (possible rare cause of clinically apparent liver injury) … Cases may be more frequent and more severe in patients receiving higher doses or with preexisting liver disease.”
  6. The effect of Gymnema sylvestre supplementation on glycemic control in type 2 diabetes patients: a systematic review and meta-analysis (Devangan et al., Phytother Res 2021) · read 2026-08-27
    what it says
    “Our meta-analysis consisting of 10 studies with a total of 419 participants showed that GS supplementation significantly reduces fasting blood glucose (FBG) … postprandial blood glucose (PPBG) … and glycated haemoglobin (HbA1c)”
  7. Devangan et al. 2021 — how the effect was calculated · read 2026-08-27
    what it says
    “Standardized mean difference (SMD) was calculated by comparing the post-intervention data with baseline data.”
  8. HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev. No. 001 (Oct 2025) — gymnema / Gymnema sylvestre / gurmar not listed in Annex A or B (PDF full text searched) · read 2026-08-27
    what it says
    “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.”
  9. iHerb Singapore — “Gymnema Sylvestre: Leaf Extract Capsules & Blends” category page, default (best-selling) order; no Singapore shipping-restriction notice shown · read 2026-08-27
    what it says
    “Swanson Vitamins, Full Spectrum Gymnema Sylvestre Leaf, 400 mg … NOW Foods, Gymnema Sylvestre Extract, 90 Veg Capsules … Source Naturals, Sugar Ban … Source Naturals, Gymnema Sylvestre, 450 mg … Himalaya … Vitacost”
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Updated 2026-08-29. 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.