Gymnema sylvestre

Principal Proposed Uses

  •Diabetes

Native to the forests of India, Gymnema sylvestre (also called gumar) has a coincidental double relationship to sugar: When placed on the tongue, it blocks the sensation of sweetness, and when taken internally, it might help control blood sugar levels in people with diabetes.

Practitioners of Ayurveda (the traditional medicine of India) first used gymnema to treat diabetes almost 2,000 years ago. In the 1920s, preliminary scientific studies found some evidence that gymnema leaves can reduce blood sugar levels,1 but nothing much came of this observation for decades. Research in India picked up again in the 1980s and 90s, leading to the publication of promising preliminary studies in people.

What Is Gymnema Used for Today?    

Gymnema has become increasingly popular in the United States as a supportive treatment for diabetes. However, the evidence that it works remains weak. Current evidence is limited to a few animal studies and human open trials.2-9

However, there are convincing reports from individuals and pharmacists who have been very successful in treating patients with borderline fasting blood sugar levels. This means, an individual may not sufficiently metabolize or utilize glucose present in the blood, leading to slightly elevated sugar level that still does not qualify them to be regarded as diabetics, ie a condition known as IGT or impaired glucose tolerance. IGT is one of the signs that usually occur before full blown diabetes mellitus develops in the course of a few years.

Alternatively, gymnema may be taken together with oral hypoglycemic agents to better control blood sugar levels. Either way, self medication for potent herbs such as gymnema must always be with the supervision of a qualified and experienced pharmacist, with frequent blood sugar level monitoring.

Dosage

Gymnema is usually taken at a dosage of 400 to 600 mg daily of an extract standardized to contain 24% gymnemic acid.

Safety Issues

When used in appropriate dosages, gymnema appears to be fairly safe, although extensive studies have not been performed. One obvious risk is that if gymnema is successful, it may lower blood sugar levels too far, causing a dangerous hypoglycemic reaction. For this reason, medical supervision is essential.

Safety in young children, pregnant or nursing women, or those with severe kidney or liver disease has not been established.

Interactions You Should Know About

If you are taking insulin or oral medications to reduce blood sugar levels, gymnema might cause them to work even better, potentially causing hypoglycemia. Therefore, you may need to reduce your dose of medication. Please ask your pharmacist or physician.

Warning: This herb is advocated as a support to standard treatment, not as a replacement for it. Gymnema definitely cannot be used as a substitute for insulin treatment, and has not been proven strong enough for use in lieu of oral diabetes medications. However, there are also potential risks involved in adding gymnema to an existing  treatment regimen. See Safety Issues.

References

1. Lininger SW, Wright J, Austin S, et al. The Natural Pharmacy. Rocklin, Calif: Prima Publishing; 1998:276

2. Shanmugasundaram ER, Rajeswari G, Baskaran K, et al. Use of Gymnema sylvestre leaf extract in the control of blood glucose in insulin-dependent diabetes mellitus. J Ethnopharmacol. 1990;30:281–294.

3. Baskaran K, Kizar Ahamath B, Radha Shanmugasundaram K, et al. Antidiabetic effect of a leaf extract from Gymnema sylvestre in non-insulin–dependent diabetes mellitus patients. J Ethnopharmacol. 1990;30:295–300.

4. Joffe DJ, Freed SH. Effect of extended release Gymnema sylvestre leaf extract alone or in combination with oral hypoglycemics or insulin regimens for Type 1 and Type 2 diabetes. Diabetes Control Newsl. 2001;76(1):1-4.

5. Shanmugasundaram KR, Panneerselvam C, Samudram P, et al. Enzyme changes and glucose utilisation in diabetic rabbits: the effect of Gymnema sylvestre.J Ethnopharmacol. 1983;7:205-234.

6. Prakash AO, Mathur S, Mathur R. Effect of feeding Gymnema sylvestre leaves on blood glucose in beryllium nitrate treated rats. J Ethnopharmacol. 1986;18:143-146.

7. Shanmugasundaram ER, Gopinath KL, Radha Shanmugasundaram K, et al. Possible regeneration of the islets of Langerhans in streptozotocin-diabetic rats given Gymnema sylvestre leaf extracts. J Ethnopharmacol. 1990;30:265-279.

8. Shimizu K, Iino A, Nakajima J, et al. Suppression of glucose absorption by some fractions extracted from Gymnema sylvestre leaves. J Vet Med Sci. 1997;59:245-251.

9. Chattopadhyay RR. Possible mechanism of antihyperglycemic effect of Gymnema sylvestre leaf extract, part 1. Gen Pharmacol. 1998;31:495-496.

Last reviewed August 2003 by HealthGate CAM Medical Review Board

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