Supplement
Gymnema sylvestre
Two-hour glucose and HbA1c A blood test that reflects average blood sugar over the previous two to three months. in one 12-week trial of 30 adults with impaired glucose tolerance, and fasting glucose in a 2023 meta-analysis A study that pools the numbers from several trials into one combined estimate. of six trials that its authors rate low quality and heterogeneous.
Grade C: human trials exist, but they are small, mixed or not yet repeated. This is not a finding that it does not work. How to read a grade →
Gymnema is a plant from India sold for blood sugar. In one 12-week study of 30 adults with high blood sugar, it lowered two blood sugar tests. A review of six studies found lower fasting blood sugar, but its authors judged the studies to be weak and very different from each other.
- Dose studied
- 300–600 mg/day
- Form graded
- Gymnema sylvestre (standardized gymnemic acids)
- Cited PMIDs PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed.
- PMID 28459647 →
A letter describes the human evidence, not the product, the manufacturer, or the ingredient's worth.
See the full evidence record →Who responds: this record's trial reading reports no subgroup that identifies who responds.
Gymnema sylvestre for glycemic markers, graded on human trial evidence.
How this letter has changed · latest: October 2026 · Corrected
The ref said Zuñiga 2017 (PMID 28459647) affected glycemic measures; it did not change the metabolic syndrome components, insulin secretion or insulin sensitivity, and was positive only for weight, BMI and VLDL, so it is now labeled null on glycemic outcomes. The positive glycemic data come from Gaytán Martínez 2021 (PMID 32460589), 2-hour glucose and HbA1c lower in 30 adults with impaired glucose tolerance, and Zamani 2023 (PMID 36580574), a six-trial meta-analysis its authors rate low quality; both are added and the best-use line now rests on them. The record now names the populations studied, none of them healthy adults. Shiyovich 2010 (PMID 20856101), toxic hepatitis attributed to Gymnema, is added to the avoid field. Letter unchanged.PMID 28459647 PMID 32460589 PMID 36580574 PMID 20856101
Every change to a letter on this site is dated and published. The full evidence log →
Commercial disclosure
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No dose is published here. This record carries no authored dose, because the cited trials do not converge on a single figure. Each trial cited on this page states the dose it used, and EBL has not turned those into a recommendation.
Standardized extracts/forms were used in the cited trials; product quality varies.
In the cited trial, a 300 mg capsule was taken before breakfast and before dinner (PMID 28459647).
Checked against the published summary; the full paper could not be read. What the cited trials did, not a schedule. Every supplement, by trial timing →
Pregnancy. Anyone whose glucose is already being driven low by treatment. Liver injury: a published case of toxic hepatitis attributed to Gymnema sylvestre taken for type 2 diabetes (Shiyovich 2010, PMID 20856101). The trials enrolled people with impaired glucose tolerance, metabolic syndrome or type 2 diabetes, so there is no safety record in healthy adults.
Diabetes medication, including insulin and sulfonylureas. Gymnema appears in the pooled herbal glycemic-control evidence as an agent that lowers glucose, so the effect is additive and hypoglycemia is the failure mode.
Herbal glucose lowering is additive to diabetes medication. Pooled randomized evidence shows several of these botanicals lower glucose in type 2 diabetes, which is the basis for treating the combination with insulin or a sulfonylurea as additive rather than neutral. Suksomboon et al. (Journal of Ethnopharmacology, 2011; PMID 21843614): meta-analysis of herbal supplements and glycemic control in type 2 diabetes. Kumar et al. (Diabetes and Metabolic Syndrome, 2023; PMID 37451111): network meta-analysis comparing six herbs on glycemic status in type 2 diabetes.
Fasting blood glucose and HbA1c at baseline and 12 weeks. Postprandial glucose with a CGM if available. Gymnema may potentiate blood sugar lowering by other agents: monitor for hypoglycemia and adjust medication as needed with physician oversight.
Primary evidenceFour papers, each linked to its PubMed record.
Gaytán Martínez et al. (J Med Food, 2021; PMID 32460589): randomized double-blind placebo-controlled trial, 30 adults with impaired glucose tolerance, 300 mg twice daily for 12 weeks; 2-hour glucose, HbA1c, body weight, BMI and LDL Low-density lipoprotein cholesterol, the cholesterol fraction most closely tied to plaque in the arteries. fell and the Matsuda insulin-sensitivity index rose against placebo An inactive substitute made to look like the real treatment, so participants cannot tell which one they received.. Zamani et al. (Phytother Res, 2023; PMID 36580574): meta-analysis of six randomized trials in adults; fasting glucose, triglycerides, total and LDL cholesterol and diastolic pressure lower, with the authors flagging notable heterogeneity How much the results of the pooled trials differ from each other. High heterogeneity makes a combined estimate less reliable. and low study quality. Zuñiga et al. (J Med Food, 2017; PMID 28459647): randomized double-blind placebo-controlled trial, 24 adults with metabolic syndrome, 600 mg/day for 12 weeks; body weight, BMI and VLDL fell, with NO change in the metabolic syndrome components, insulin secretion or insulin sensitivity, so it is null on glycemic outcomes. Safety: Shiyovich et al. (Am J Med Sci, 2010; PMID 20856101): case report of toxic hepatitis attributed to Gymnema sylvestre taken for type 2 diabetes. Grade C: one small positive glycemic trial, one null, and a low-quality pooled analysis, all on surrogate endpoints A lab value or measurement used in place of the outcome that matters, such as LDL cholesterol standing in for heart attacks. Moving a surrogate does not always move the outcome. in people with impaired glucose handling.
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These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. The grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Starting, stopping or changing any supplement or medication is a decision for your physician.
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How EBL searched for the trials (1 search)
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