Gymnema sylvestre supplements may help lower both fasting and postmeal blood sugar levels.[1][2] This could potentially help people with diabetes improve their sugar control, and could potentially also help prevent people with prediabetic blood sugar levels from progressing to diabetes. GS supplementation may also help lower triglycerides, total cholesterol, and LDL cholesterol levels, which could lower cardiovascular disease risk.[3][1]
GS could potentially also help with stomach ulcers, as some evidence shows that it improves gastric emptying, raises the pH level of stomach acid and decreases the volume of gastric juices.[4]
While the effects of GS sound promising, some of these studies have been done only in rats, and some are not of high quality. More randomized clinical trials will need to be done in the future to support these findings.