Gymnema stimulates Islets of Langerhans - cells in pancreas which secretes insulin and hence finds use in treatment of type I diabetics or insulin-dependent diabetes. An in-vitro study confirmed that extract of gymnema leaves increase membrane permeability of cells that secrete insulin. A similar study found efficacy of Gymnema leaf extract treatment on patients with insulin dependent diabetes mellitus and its use in treatment of type I diabetes.
Diabetes mellitus type 2 or non insulin-dependent diabetes mellitus is a metabolic disorder characterized by high blood glucose due to insulin resistance and relative insulin deficiency and is often caused by is caused by a combination of lifestyle and genetic factors. A human study with extract from leaves of Gymnema found effective in controlling hyperglycaemia in Type 2 diabeties patients. In the study, long term dosage of Gymnema supplements resulted in reduction of blood glucose and reduced need for conventional medicines.