How Is Metformin Used for Weight Loss?

From as early as the middle of the 1990s, researchers have been exploring a possible link between the drug metformin (Glucophage) and weight loss. A 1996 study by A. Fontbonne, M. Charles and I. Juhan-Vague published in Diabetes Care found that among other benefits like lower cholesterol, patients taking metformin lost weight. But despite this promising start, metformin does not appear to be the "magic bullet" weight loss pill that researchers are hoping to find.

Use

The primary use of metformin is to treat type 2 diabetes mellitus, a disease in which the body either does not produce enough insulin, does not use the insulin it does produce effectively or is a combination of the two. Insulin is a hormone secreted by the pancreas. It transports glucose (sugar) into the cells so that the cells can use them as fuel. Any remaining insulin then stimulates hunger, helps the body store excess blood sugar and helps convert extra blood sugar into fat.

Function

Metformin is part of the class of drugs known as biguanides. Metformin lowers blood sugar in type 2 diabetes by helping the body use insulin more efficiently and slowing the absorption of sugar in the intestine. When metformin is prescribed to diabetics or obese people at risk for developing diabetes, they often lose weight.

Effects

Overweight people are often insulin resistant, even if they do not have diabetes. Insulin resistance is when the body does not use insulin effectively, stimulating the pancreas to release extra insulin to compensate. Excess insulin in the system starts the cycle of hunger stimulation and fat storage. Since metformin halts this cycle, it is a logical assumption that weight loss will follow.

Potential

Studies have demonstrated that patients considered borderline diabetic lose weight when they are given metformin, but usually only when the patients also makes lifestyle changes. A 2008 study by A.E. Nieuwenhuis-Ruifrok published in Human Reproduction Update found that overweight women given metformin did lose weight, but researchers say that diet and exercise should still be tried first.

Warning

Metformin causes diarrhea and upset stomach in some people, but this often goes away with time. It should not be used in patients with kidney or liver problems. It should also be avoided in patients with some heart and lung problems that causes them to have low oxygen levels in their blood. Muscle pain, drowsiness and difficulty breathing are signs of a rare but serious side effect called lactic acidosis. Patients who have any of these symptoms should contact their doctor right away.

References

• Diabetes Care; The Effect of Metformin on the Metabolic Abnormalities Associated With Upper-body Fat Distribution; A. Fontbonne, M. Charles, and I. Juhan-Vague; 1996
• Basic and Clinical Pharmacology; Bertram Katzung; 2007
• Human Reproduction Update; Insulin Sensitizing Drugs for Weight Loss in Women of Reproductive Age Who Are Overweight or Obese; A.E. Nieuwenhuis-Ruifrok; October 2008