Metformin is an oral antidiabetic drug in the biguanide class. It is also used in the treatment of polycystic ovary syndrome, and has been investigated for other diseases where insulin resistance may be an important factor. Metformin works by suppressing glucose production by the liver.
Metformin is the only antidiabetic drug that has been conclusively shown to prevent the cardiovascular complications of diabetes.. It helps reduce LDL cholesterol and triglyceride levels, and is not associated with weight gain.