Insulin Resistance and Weight Loss with Metformin

The cells in your body can't absorb glucose, the body's primary source of energy, without insulin. When glucose enters the bloodstream, the pancreas releases insulin. If cells become insulin-resistant, they no longer respond to insulin release by absorbing glucose. More glucose stays in the bloodstream, a condition known as hyperglycemia. Once this happens, a person is diagnosed with type 2 diabetes, formerly called adult-onset diabetes. Metformin is a medication that can improve the cells' sensitivity to insulin; weight loss may occur, as well.

Syringe and bottle of insulin
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Causes of Insulin Resistance

Insulin resistance occurs most often in people who have a family history of the disorder, overweight people and women who have polycystic ovary disease, a hormonal disorder characterized by insulin resistance and an over-production of male hormones called androgens. Inactivity also contributes to insulin resistance. Insulin resistance may have no obvious symptoms outside of weight gain. Metabolic syndrome, a disorder that includes insulin resistance and borderline high glucose levels, also includes excess weight around the waist, high blood pressure and abnormal cholesterol levels.

Weight Gain and Insulin Resistance

People with insulin resistance often gain weight. When blood sugar goes up, the pancreas release insulin. If cells don't absorb glucose, the pancreas releases ever larger amounts of insulin in an effort to "force" cells to absorb the glucose. Eventually, insulin levels remain higher than normal in the bloodstream. Since high insulin levels increase hunger, people with high insulin levels often gain weight. Drugs like metformin that lower insulin can result in weight loss.


Metformin attaches to the surfaces of cells and increases their ability to take in glucose. The drug also reduces glucose production in the liver. Metformin is the only drug that should be considered for use in insulin resistance or pre-diabetes to prevent diabetes onset, the American Diabetes Association suggests.


Researchers from the University of Naples published an article in the June 1998 issue of the "European Journal of Clinical Investigation" on the effects of metformin on food intake and weight loss. The metformin group ate less and lost more weight and body fat compared to the placebo group over a 15 day period. Body weight dropped -2.8 +/- 1.6 kg in the metformin group compared to -0.3 +/- 0.4 kg in the placebo group. Taking metformin to treat insulin resistance also decreases the chance that a person will develop type 2 diabetes. Losing weight and increasing activity greatly reduce the risk of developing type 2 diabetes. Losing 5 percent to 7 percent of body weight can delay or prevent the onset of diabetes by as much as 60 percent, according to the National Institute of Diabetes and Digestive and Kidney Disorders.

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