Metformin is a medication that normally is used in the treatment of type 2 diabetes mellitus. This medication is in the antihyperglyemic drug class, meaning that it counteracts glucose in the blood.
While the Food and Drug Administration has not approved metformin for weight loss in the United States, some physicians are starting to utilize this medication in an off-label manner to decrease weight in patients with overweight or obesity. Several studies are underway analyzing the use of metformin for weight loss, and more studies are needed before FDA approval.
Decreased Hepatic Glucose Production
Metformin decreases the amount of sugar that is created by the liver, according to findings from the Glaser Obesity Study, conducted by the Glaser Pediatric Research Network. If you haven't eaten in some period of time and your blood sugar becomes too low, your liver can compensate by creating and releasing sugar into the blood. Insulin is then secreted to compensate, and stores this sugar as fat in adipose tissue. When metformin decreases the amount of sugar released by the liver, the pancreas does not have to release extra insulin, thus reducing fat production and storage.
Decreased Food Intake
Research has indicated that metformin may have an appetite-suppressing effect, though it is not completely understood why this occurs at the present time, according to the Weight-control Information Network. The network also states that metformin may make you feel satisfied quicker and for a longer period of time than normal.
Gastrointestinal Side Effects
Metformin may cause mild gastrointestinal side effects including diarrhea, nausea and vomiting, according to Drugs.com. It is proposed that one possible mechanism of action for the weight-reducing benefit of metformin is simply that because of these mild gastrointestinal side effects people do not feel like eating, notes the Glaser research. If you have excessive or prolonged gastrointestinal upsets while taking metformin, contact your physician as he may need to change your medication.
Reduced Insulin Resistance
Metformin creates increased insulin sensitivity by assisting the body in using the blood sugar already present. This process decreases the release of glucagon and glucogenesis to increase blood sugar levels. Because metformin helps the body use blood sugar rather than store it, less fat is created and stored by the body.
- PubMed.gov; Utility of Metformin as an Adjunct to Hydroxycitrate/Carnitine for Reducing Body Fat in Diabetics; "Medical Hypotheses"; M.F. McCarty; November 1998
- ClinicalTrials.gov; Glaser Obesity Study
- PubMed Central; Treating Diabetes and Prediabetes by Focusing on Obesity Management; "Current Diabetes Reports"; Lalita Khaodhiar et al.; October 2009
- WIN; Prescription Medications for the Treatment of Obesity; December 2010
- Drugs.com; Glucophage