Gymnema Sylvestre
Summary
Gymnema is marketed for blood sugar control and sugar cravings. Human evidence is small: uncontrolled 1990 studies and one 30-person prediabetes trial reported lower glucose markers (grade D), and pooled analyses mostly compare against baseline. It may add to the glucose-lowering effect of diabetes medicines, so hypoglycemia is the main concern.
Key facts
- Leaf extract of Gymnema sylvestre; gymnemic acids (triterpene saponins) are the signature compounds[1]
- Glucose tolerance in prediabetes: 2-hour glucose and A1C fell on 300 mg twice daily in a 30-person trial (D)[4]
- A meta-analysis of 6 RCTs reported lower fasting glucose and lipids, but noted low study quality and high heterogeneity[5]
- May enhance the glucose-lowering effect of diabetes medicines, raising hypoglycemia risk[8]
- 5 graded human outcomes on this page
- October 12, 2026
How it works
ProposedGymnemic acids bind and block sweet taste receptors, which dulls sweet taste. Lab and animal studies show glucose-lowering effects; the claim that gymnema regenerates insulin-producing cells comes from uncontrolled 1990 human studies and is not established.[1][2][3]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Type 2 diabetes | Grade C | Improved | Meta-analysis of 10 trials · n = 419 · 2021 | 2 rows |
| Sugar cravings | Grade D | Mixed | RCT · n = 58 · 2022 | 1 row |
| Prediabetes | Grade D | Improved | RCT · n = 30 · 2021 | 1 row |
| Type 1 diabetes | Grade D | Improved | Open-label · n = 27 · 1990 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Fasting glucose, post-meal glucose and HbA1c | Improved | Grade C | Meta-analysis · n = 419 · 2021 Adults with type 2 diabetes in 10 studies Form: Gymnema sylvestre preparations (varied) · Dose: Varied · Duration: Varied Fasting glucose, post-meal glucose, HbA1c, triglycerides and cholesterol fell compared with baseline, with very high heterogeneity (I² 80–99%). Effects were measured against baseline, not placebo. | 34467577 (opens PubMed)Source [6] |
| Chocolate intake and sweet-food intake | Mixed | Grade D | RCT · n = 58 · 2022 Healthy adults Form: Gymnema sylvestre (75% gymnemic acids) with a fibre and vitamin supplement and healthy-eating guide · Dose: 4 mg of gymnema per dose · Duration: 14 days Right after a dose, the gymnema group ate fewer chocolate bars than the placebo-mint group (2.65 vs 3.15); by day 15 there was no difference, and intake of 9 food categories did not differ. | 36558446 (opens PubMed)Source [7] |
| 2-hour glucose, A1C and insulin sensitivity | Improved | Grade D | RCT · n = 30 · 2021 Mexican adults with impaired glucose tolerance (prediabetes) Form: Gymnema sylvestre capsules · Dose: 300 mg twice daily · Duration: 90 days (per ClinicalTrials.gov NCT02708966; not stated in the abstract) In the gymnema group, 2-hour glucose fell from 9.1 to 7.8 mmol/L and A1C from 5.8% to 5.4%, with lower weight, BMI and LDL and better insulin sensitivity; 46.7% reached a normal A1C. The abstract reports within-group changes rather than a direct comparison with placebo. | 32460589 (opens PubMed)Source [4] |
| Insulin needs and HbA1c in type 1 diabetes | Improved | Grade D | Open-label trial · n = 27 · 1990 Indian adults with type 1 diabetes on insulin Form: GS4 water-soluble leaf extract · Dose: 400 mg/day · Duration: Not stated in the abstract Insulin requirements, fasting glucose and HbA1c fell, though HbA1c stayed above that of healthy controls. Compared only with patients on insulin alone, not with placebo. | 2259216 (opens PubMed)Source [3] |
| Blood glucose and HbA1c in type 2 diabetes | Improved | Grade D | Open-label trial · n = 22 · 1990 Indian adults with type 2 diabetes on oral glucose-lowering drugs Form: GS4 water-soluble leaf extract · Dose: 400 mg/day · Duration: 18–20 months Blood glucose and HbA1c fell and drug doses could be lowered; 5 of 22 stopped their conventional drug. No control group. | 2259217 (opens PubMed)Source [2] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Leaf extract capsules (often standardized to gymnemic acids) | Varies[4][2] | No human absorption data in our sources.[1] | No significant adverse events reported in the small trials; isolated liver injury reports with weak attribution.[1][8] | Prediabetes and type 2 diabetes markers (300–600 mg/day in trials) |
| GS4 water-soluble leaf extract | Varies[2][3] | No human absorption data in our sources.[2] | Patients needed lower doses of diabetes drugs or insulin while using it.[2][3] | Type 1 and type 2 diabetes in uncontrolled 1990 studies (400 mg/day) |
| Gymnema mints or lozenges | Varies[7] | Acts in the mouth by blocking sweet taste receptors.[1][7] | No habituation to the mint over 14 days.[7] | Short-term sweet-food intake |
Studied doses
Doses studied in human trials ranged from a 4 mg gymnema mint for sweet cravings over 14 days, through 400 mg/day of the GS4 extract for up to 20 months in uncontrolled studies, to 300 mg twice daily for 90 days in prediabetes.[2][4][7]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Who should be careful
- People on diabetes medicines
- Combined use may lower blood sugar too far; the EFSA risk assessment flags risk with authorised antidiabetic drugs.[8][2][3]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Blood sugar and liver
Hypoglycemia with diabetes medicines is the main concern; liver reports are rare.
- Hypoglycemia
- Glucose-lowering effects may add to those of antidiabetic drugs; the evidence comes from 1990 uncontrolled studies where drug doses had to be lowered.[8][2][3]
- Liver
- LiverTox notes isolated, rare liver injury reports from gymnema-containing products, with usually weak attribution.[1]
- Case report
- A 2010 case report described drug-induced liver injury in a patient using gymnema for diabetes.[9]
- Trial tolerability
- The EFSA review found limited animal and human data suggesting no relevant adverse effects apart from glucose lowering.[8]
How to read the label
- Label dose vs clinical doseGlucose studies used 400 mg/day of the GS4 extract or 300 mg twice daily of leaf extract; the sweet-craving trial used a 4 mg mint. Check the extract and its gymnemic acid percentage rather than the leaf weight.[2][4][7]
- Before-and-after is not proofThe 2021 type 2 diabetes meta-analysis compared results with baseline, not with placebo.[6]
- Composition variesEFSA notes uncertainty about the composition of different gymnema preparations.[8]
Frequently asked questions
Does gymnema lower blood sugar?
Small and mostly uncontrolled studies report lower glucose and A1C. The best trial, in 30 adults with prediabetes, found lower 2-hour glucose and A1C on 300 mg twice daily.[4][2]
Is gymnema safe with diabetes medication?
It may increase the risk of low blood sugar. In 1990 studies, patients' insulin or drug doses were reduced while using it; that evidence was uncontrolled.[2][3][8]
Does gymnema stop sugar cravings?
In a 14-day trial, a gymnema mint cut chocolate intake right after a dose, but the effect was gone by day 15.[7]
Sources
- [1]Gymnema. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury.. NIDDK, 2024. database
- [2]Antidiabetic effect of a leaf extract from Gymnema sylvestre in non-insulin-dependent diabetes mellitus patients.. J Ethnopharmacol, 1990. open-label
- [3]Use of Gymnema sylvestre leaf extract in the control of blood glucose in insulin-dependent diabetes mellitus.. J Ethnopharmacol, 1990. open-label
- [4]Effect of Gymnema sylvestre Administration on Glycemic Control, Insulin Secretion, and Insulin Sensitivity in Patients with Impaired Glucose Tolerance.. J Med Food, 2021. RCT
- [5]The effects of Gymnema Sylvestre supplementation on lipid profile, glycemic control, blood pressure, and anthropometric indices in adults: A systematic review and meta-analysis.. Phytother Res, 2023. meta-analysis
- [6]The effect of Gymnema sylvestre supplementation on glycemic control in type 2 diabetes patients: A systematic review and meta-analysis.. Phytother Res, 2021. meta-analysis
- [7]The Effect of a 14-Day gymnema sylvestre Intervention to Reduce Sugar Cravings in Adults.. Nutrients, 2022. RCT
- [8]Risk assessment of substances used in food supplements: the example of the botanical Gymnema sylvestre.. EFSA J, 2018. review
- [9]Toxic hepatitis induced by Gymnema sylvestre, a natural remedy for type 2 diabetes mellitus.. Am J Med Sci, 2010. observational
What changed
- First draft (rebuilt after a lost earlier draft). Every PMID checked against NCBI E-utilities esummary (title and year) and the cited abstracts read; no retraction or erratum flagged for any cited PMID. Prediabetes trial duration (90 days) and sponsor (University of Guadalajara) checked on ClinicalTrials.gov NCT02708966. No product links.
- Independent adversarial review (PR #201): spot-checked the prediabetes trial, both 1990 studies, both meta-analyses, the sugar-craving trial and EFSA against PubMed abstracts. No changes needed.