The typical therapeutic dose of an extract, standardised to contain 24% gymnemic acids, is 400-600 mg/day. When used to regulate blood sugar, gymnema may best be administered in divided doses with meals.
• Liquid extract (1:1): 25-75 mL/weekor 3.6-11.0 mL/day.
• 6-60 g/day of dried leaf infusion
SWEET CRAVING AND REDUCING SWEET PERCEPTION
• Liquid extract (1:1): 1-2 mL dropped onto the tongue and rinsed off — repeat every 2-3 hours as required.
Theoretically, gastric irritation can occur, because of the saponin content. There are two case reports of hepatotoxicity resulting from the consumption of a weight-loss formula containing gymnema and other herbs, including Garcinia cambogia, willow bark, glucomannan, green tea and guarana. In one study, gymnema was found to have a toxic effect in mice, producing increased lipid peroxidation at doses of 26.8 mg/kg, but was safe and antiperoxidative at doses of 13.4 mg/kg. In another study it was concluded that there was no toxic effect in rats treated with gymnema at doses of more than 500 mg/kg for 52 weeks.
Controlled studies are not available; therefore, interactions are based on evidence of activity and are largely theoretical and speculative.
HYPOGLYCAEMIC AGENTS AND INSULIN
Gymnema may enhance the blood-glucose-lowering effects of insulin and hypoglycaemic agents, so should be used with caution. In practice the interaction may be useful, as a reduction in the drug dose could theoretically be achieved under professional supervision.
Contraindications and Precautions
Blood glucose levels should be monitored closely when used in conjunction with insulin and hypoglycaemic agents.
There is insufficient reliable information available about the safety of gymnema in pregnancy.
Practice Points / Patient Counselling
• Gymnema suppresses the ability to taste sweet on the tongue.
• It may be useful as a weight-loss aid.
• Clinical studies have shown that gymnema can be used to help control blood sugar levels in diabetes.
• When used with hypoglycaemic medications, blood sugar levels need to be monitored to prevent hypoglycaemia.
• Preliminary research suggests that it may also have a role in elevated cholesterol and triglyceride levels.
Answers to Patients’ Frequently Asked Questions
What will this herb do for me?
Gymnema has the uncanny ability to reduce the tongue’s perception of sweetness. It can also stabilise blood sugar levels and may be useful as a weight-loss aid.
When will it start to work?
It reduces the taste of sweetness rapidly, lasting for several hours, but effects on blood sugar develop with long-term use.
Are there any safety issues?
Diabetic patients on medication should carefully monitor their blood sugar levels when taking this herb, because it may further reduce levels.