Gymnema
EVIDENCE: WEAKAlso sold as: Gymnema sylvestre, gurmar, sugar destroyer, GS4
Gymnema is an Ayurvedic leaf used for blood sugar. Small human trials, mostly at 400–800 mg of extract a day, report lower fasting glucose and HbA1c, but the studies are small and often unblinded.
Compiled by iSupplementReviews editorial team ·Researched 2026-10-16 · 3 sources
- Type
- Botanical leaf extract
- Studied dose
- 400–800 mg/day of leaf extract (often the GS4 extract)
- Best form
- standardized leaf extract with stated gymnemic acid content
- Our rating
- WEAK — Mostly small, animal, or traditional evidence
What is gymnema?
Gymnema (Gymnema sylvestre) is a climbing plant from India whose leaves are used in Ayurveda to support blood sugar. Its active compounds are called gymnemic acids.
Other names and forms
Gurmar (“sugar destroyer” in Hindi), Gymnema sylvestre, and GS4, a specific leaf extract used in the early trials. Products range from raw leaf powder to extracts standardized to 25% or 75% gymnemic acids.
Where does gymnema come from?
The leaves of a woody vine native to India, Africa and Australia.
How does gymnema work in the body?
Gymnemic acids briefly block sweet taste receptors on the tongue. In the gut they may slow sugar absorption, and lab studies suggest effects on insulin-producing cells. The gut and pancreas mechanisms are proposed, not established in people.
What is gymnema claimed to do?
Lower blood sugar, reduce sugar cravings, support weight loss and improve cholesterol.
What does the research show?
| Claim | Evidence | Dose studied | Verdict |
|---|---|---|---|
| Lower glucose/HbA1c in type 2 diabetes | Small trials + meta-analyses | 400–800 mg/day extract | Early positive |
| Reduced sweet taste and cravings | Taste studies | Leaf or lozenge on tongue | Shown for taste |
| Weight loss | Few trials | — | Insufficient |
The early trial
An open-label 1990 study found lower glucose and HbA1c when 22 people added gymnema extract to their diabetes medicine. Baskaran et al. gave 400 mg a day of the GS4 extract for 18–20 months. There was no placebo group, so the result is a signal, not proof.
The meta-analyses
Two meta-analyses found lower fasting glucose and HbA1c, built on small and mixed-quality trials. Devangan et al. (2021) pooled trials in type 2 diabetes. Zamani et al. (2023) also reported improvements in glucose and lipid markers and noted high variation between studies.
What dose was studied?
| Goal | Dose | Duration |
|---|---|---|
| Glucose in type 2 diabetes | 400–800 mg extract/day | 3–20 months |
| Sweet-taste suppression | Leaf contact on tongue | Minutes |
Amounts in the tens of milligrams are a small fraction of the trial range.
Side effects
Mild stomach upset. Rare case reports describe liver injury.
Drug interactions
- Insulin and diabetes medicines: may increase the risk of low blood sugar (moderate).
Who should not take gymnema?
People who are pregnant or breastfeeding (no safety data), and anyone on diabetes medicine without medical advice.
What the authorities say
No regulator has approved gymnema for diabetes, and the published reviews describe its glucose evidence as preliminary. Both meta-analyses above call for larger, placebo-controlled trials.
What to know about gymnema
Gymnema has early human evidence for modestly lower blood sugar at about 400 mg of extract a day or more. The trials are small, and it should not replace prescribed treatment.
Frequently asked questions about Gymnema
Does gymnema lower blood sugar?
Possibly a little. Small trials in people with type 2 diabetes, usually at 400 mg or more of extract a day, reported lower fasting glucose and HbA1c, and a 2021 meta-analysis found the same direction. The trials are small and many were not placebo-controlled.
Why is gymnema called the sugar destroyer?
Chewing the leaf briefly blocks your ability to taste sweetness. That effect on the tongue is well documented; it is separate from any effect on blood sugar after swallowing.
Can gymnema cause low blood sugar?
It may add to diabetes medicines. If you use insulin or glucose-lowering pills, check your readings and talk to your doctor before starting it.
References
- [1]Baskaran K et al. — Antidiabetic effect of a leaf extract from Gymnema sylvestre in non-insulin-dependent diabetes mellitus patients (J Ethnopharmacol, 1990)
- [2]Devangan S et al. — The effect of Gymnema sylvestre supplementation on glycemic control in type 2 diabetes patients: a systematic review and meta-analysis (Phytother Res, 2021)
- [3]Zamani M et al. — The effects of Gymnema sylvestre supplementation on lipid profile, glycemic control, blood pressure and anthropometric indices: a systematic review and meta-analysis (Phytother Res, 2023)
Products we reviewed containing Gymnema
Based on recorded labels or seller-described formulas. Inclusion does not establish a match to the strains, preparations or amounts studied here; check each review's disclosure limits.