Metformin HCL. Metformin HCl (Glucophage ®) is a medication that is often prescribed to treat diabetes. It is used for decreasing blood sugar levels in people with type 2 diabetes. Metformin HCl is an abbreviation for metformin hydrochloride.The medication works in several ways.etformin HCL. Metformin HCl (Glucophage ®) is a medication that is often prescribed to treat diabetes. It is used for decreasing blood sugar levels in people with type 2 diabetes. Metformin HCl is an abbreviation for metformin hydrochloride.