NHS medicines information on metformin – what it's used for, side effects, dosage and who can take it. Metformin is used to treat high blood sugar levels that are caused by a type of diabetes mellitus or sugar diabetes called type 2 diabetes. With this type of diabetes, insulin produced by the pancreas is not able to get sugar into the cells of the body where it can work properly. Overview: Metformin is medicine you take to help keep your blood sugar from getting too high. Common side effects may include stomach problems, such as diarrhea, nausea, vomiting, stomach pain. Metformin doesn’t just manage diabetes—it reshapes copper, iron, and zinc levels in the body, a potential clue to its broad protective effects. Metformin is a first-line treatment used for type 2 diabetes in adults and children 10 years and older to help improve blood sugar levels. It is also used off-label to improve symptoms of polycystic ovarian syndrome (PCOS) and other conditions. Metformin is a generic prescription medication used to help manage blood sugar levels in adults and some children with type 2 diabetes. It works by decreasing sugar production in the liver. Medical uses Metformin is used to lower blood glucose in those with type 2 diabetes. [15] It has also been used to help with metabolic abnormalities in polyendocrine metabolic ovarian syndrome (PMOS), and as a second-line agent for infertility in those with PMOS. [15][34] Metformin is a common treatment for diabetes. But it can cause digestive problems and other side effects. Learn more about the uses and side effects here. Learn about the side effects of metformin, from common to rare, for consumers and healthcare professionals. Learn more about how metformin works, its side effects, and what to expect when taking this medication.