Gymnema sylvestre, a plant originally from India, has long been used in traditional medicine and is known as “the destroyer of sugar.” Read on to learn more about the impressive diabetes-fighting and other health benefits of Gymnema.
What is Gymnema sylvestre?
Gymnema sylvestre, the “destroyer of sugar”, gets its nickname from its effects related to sugar metabolism. It helps combat diabetes and can help with weight loss, while its most peculiar ability is to temporarily suppress the taste of sugar on the tongue.
Gymnema is also known by the common names cowplant, gurmar, and periploca of the woods, and the scientific names Asclepias geminata and Periploca sylvestris .
The extracts of Gymnema sylvestre are usually prepared from the leaves, although the roots are also used in traditional medicine .
One of the most important components in the leaves of Gymnema silvestre are the saponins. Saponins are molecules that help dissolve oily substances and are used in cosmetics, pharmaceutics, and as food additives. They can help reduce cholesterol and fight cancer, but can also kill red blood cells .
Gurmarin is a peptide present in the leaves, which also blocks the sweet taste in rats, but has very little effect in humans .
Other components with biological activities are :
- Steroids and cardiac glycosides
- Flavonoids, molecules that give food their attractive colors
- Essential oils
Mechanisms of Action
Blocking Sweet Taste
Gymnemic acid blocks the taste of sugar (sucrose) and other artificial sweeteners like saccharin, aspartame, and cyclamate; but does not affect other flavors. It is believed to bind with the taste buds in our tongue, blocking the interaction with sugar [2, 7].
Lowering Blood Sugar
Gymnemic acid inhibits the secretion of an enzyme (gastric inhibitory peptide) that promotes the release of insulin .
A Gymnema extract, OSA, promotes the release of insulin from the beta-cells of the pancreas by activating protein kinases and interacting with calcium channels. It also promotes the synthesis of a precursor (preproinsulin) helping maintain a steady level of stored insulin in the beta-cells [11, 12, 13].
At higher doses, gymnemic acid increases the release of insulin from the beta-cells of the pancreas by damaging their membrane, causing insulin to “leak” out .
Lowering Fat Levels in the Blood
In genetically obese rats, gymnemic acid improved fat metabolism by lowering the levels of triglycerides and total cholesterol and increasing the proportion of “good cholesterol” (HDL-cholesterol) .
Gymnema extract decreases pancreatic lipase activity, an enzyme that breaks down fat, allowing it to be absorbed by the gut. Therefore, this activity is potentially beneficial in preventing obesity .
Lowering Oxidative Stress
In obese rats, oxidative stress is increased, causing cell death and a decrease in the antioxidant defenses of the body. The use of Gymnema extract helps restore the normal levels of leptin, apolipoproteins B and A1, and caspase-3 while preventing cell death in the heart .
1) Gymnema sylvestre Helps Improve Diabetes Symptoms
Gymnema extracts help improve diabetes by the combination of several actions: it slows the absorption of glucose in the gut, stimulates the release of insulin from the pancreas while helping regenerate the cells that produce it (beta-cells), that are damaged by diabetes, and helps boost the correct use and storage of glucose in the body.
The needed drug dose was reduced in 22 patients with type 2 diabetes taking 400 mg of a Gymnema supplement (GS4) along with their medication for 18 – 20 months in a CT. 5 patients could stop their conventional treatment altogether for the duration of the trial .
When 27 patients with insulin-dependent diabetes took 400 mg a day of a Gymnema supplement (GS4) for up to 30 months in a CT, their needed insulin dose was reduced to almost half .
In a CT with 11 patients with type 2 diabetes taking 1 g a day of a Gymnema supplement (OSA) for 60 days, blood glucose decreased as a result of higher blood insulin levels .
In a CT with 8 patients with type 2 diabetes taking 500 mg of ground Gymnema leaves for 40 days, glucose levels lowered, but there was no change in fat levels (cholesterol, triglycerides, HDL or LDL) .
2) Gymnema sylvestre May Help with Weight Loss
Gymnema extracts can aid weight loss by helping control sweet cravings, and by diminishing the absorption of glucose and fat from the gut.
However, in a CT with 11 patients with type 2 diabetes, taking 1 g/day of a Gymnema supplement (OSA) for 60 days did not cause weight loss .
While the use of a Gymnema extract did not cause weight loss in normal rats, it did stop weight gain in genetically obese rats and in rats fed with high fat and cafeteria (high carb) diets [19, 24, 21, 22].
3) Gymnema sylvestre May Help Prevent Heart Disease
A high-fat diet can elevate blood levels of triglycerides and total and bad cholesterol. This is a risk factor for the narrowing and hardening of the arteries (atherosclerosis), which can develop into coronary heart disease.
4) Gymnema sylvestre Has Antioxidant Effects
Certain (phenolic) compounds present in plants act as antioxidants. The ones present in Gymnema extracts can inhibit the oxidation of fat, and decrease oxidative stress in diabetic rats as well as protecting mice from radiation-induced oxidative damage [23, 31].
5) Gymnema sylvestre Can Protect Against Ulcers
6) Gymnema sylvestre May Help with Arthritis
7) Gymnema sylvestre Has Antimicrobial Activity
Flavonoids and heart glycosides found in Gymnema extracts have antimicrobial activity .
8) Gymnema sylvestre and Immunity
9) Gymnema sylvestre and Cancer
Due to the effects of Gymnema extracts on the immune system, it has been found to kill cancer cells in some tests, while it has no toxic effects or actually diminishes cell death in other cases [36, 37, 24].
Side Effects and Risks
Very high doses (>1 g/day) can lower blood sugar to harmful levels, causing weakness, confusion, dizziness, and loss of muscle control .
Liver toxicity can occur in people with a special sensitivity to the components (idiosyncratic reaction) .
Allergic reactions may occur, especially in persons allergic to plants of the milkweed family .
Limitations and Caveats
Larger and more strict clinical trials are needed to prove the effectiveness of Gymnema extracts for diabetes, lowering blood fat levels, and weight loss .
Research on the effects of patented Gymnema extract supplements is funded by the companies that produce them, which might represent a conflict of interest.
The use of Gymnema extracts along with the following drugs can increase their effects .
Glucose-lowering (hypoglycemic) drugs, such as:
- DPP inhibitors
Weight loss drugs like:
Cholesterol/triglyceride lowering (antilipemic) medication such as:
Gymnema sylvestre in Combination with Other Supplements/Herbs
A combination of the extracts of Garcinia cambogia and Gymnema sylvestre caused a decrease in 5-6% in weight and BMI, and a decrease in blood fat levels in a DB-RCT in 60 moderately obese adults .
Forms of Supplementation
Gymnema sylvestre is available as tablets, capsules, liquid extracts, and dry leaves for preparing tea. The extracts are prepared from the leaves .
Some preparations are standardized to a specific percentage of gymnemic acids:
- Beta Fast GXR (25% gymnemic acid content)
- Gymnesyl (150 mg of crude gymnemic acids in each capsule)
- GymnePURE (OSA) (undisclosed composition)
- GS4 (ProBeta) (undisclosed composition)
Clinical trials in humans used a daily dose of 1 g of OSA .
Gymnema extracts are mostly used to help control diabetes, and some users also report using it to control sugar cravings.
Other customers take Gymnema extracts to help control their cholesterol or triglyceride levels.
Most users are satisfied with the results, others have not seen any changes in their sugar blood level from taking the supplement, and a few report their blood sugar increased when they started using Gymnema.