Metformin METFORMIN, THE MOST powerful of the biguanide class of medications, was discovered shortly after insulin and described in the scientific literature in 1922. By 1929, its sugar-lowering effect was noted in animal studies, but it was not until 1957 that it was first used in humans for the treatment of diabetes. Biguanides work by blocking gluconeogenesis and thereby preventing the liver from producing glucose. This effect lowers the risk of hypoglycemia and weight gain because it does not increase insulin levels in the body.
