Biguanides decrease how much sugar your liver makes. They decrease how much sugar your intestines absorb, make your body more sensitive to insulin, and help your muscles absorb glucose. The most common biguanide is metformin (Glucophage, Metformin Hydrochloride ER, Glumetza, Riomet, Fortamet). Metformin can also be combined with other drugs for type 2 diabetes. It’s an ingredient in the following medications:

References:

Avoid the Metformin Bandwagon
https://www.faim.org/avoid-the-metformin-bandwagon

Diabetes drug, metformin, lowers risk of heart disease deaths better than sulfonylureas
https://www.sciencedaily.com/releases/2016/04/160419081703.htm

Metformin
Metformin is in a class of drugs called biguanides. It significantly lowers blood sugar for most people. Studied in human since the 1950s, it has proven safe. Side effects tend to be minimal and temporary, though there is a minority of people who do not tolerate it well. It does not cause weight gain or low blood sugars.
https://www.diabetesdaily.com/learn-about-diabetes/overview-of-diabetes-drugs/metformin/

Metformin, the Liver, and Diabetes
https://www.diabetesselfmanagement.com/blog/diabetes-metformin-and-your-liver/

Protecting Your Kidneys
https://www.diabetesselfmanagement.com/managing-diabetes/complications-prevention/protecting-your-kidneys/

Classes of Medications