Weight gain is widely associated with medical morbidities. Metformin, the active ingredient of Janumet, has been shown to decrease weight and improve obesity-related conditions, including abnormalities in blood glucose maintenance and insulin levels. This compound shows potential for weight control, but always consult a physician before using any medication or supplement.

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Janumet is the brand-name of a commercial pharmaceutical, a combination of sitagliptin and metformin, approved to treat type II diabetes by the FDA in 2006. Metformin can stimulate the action of insulin to lower blood glucose. When used properly, metformin causes few adverse effects and is purported to be beneficial in weight management and as a diabetic medication for those who are overweight and obese but have normal kidney function.

Weight Management with Metformin

Reported in the January 2008 issue of the “Journal of the American Medical Association,” researchers tested the efficacy of metformin in psychiatric patients who experienced medication-induced weight gain and irregular insulin function. The randomized, controlled, two-year trial involved patients who had gained more than 10 percent of their pre-treatment weight. Patients continued their antipsychotic medications and were randomly assigned to receive a placebo, metformin alone, metformin and lifestyle intervention, or lifestyle intervention only. The study found that the lifestyle-plus-metformin group had significant decreases in body mass index, BMI and waist circumference. The metformin-alone group also showed decreases in BMI, insulin resistance and waist circumference, but slightly less than the group also receiving lifestyle information. The authors concluded that the lifestyle-plus-metformin treatment was significantly superior to metformin alone, which, in turn, was significantly improved over the placebo group for reductions in weight, BMI and waist circumference.

Treating Obesity in Children

The February 2011 issue of “Diabetes” published a study on whether metformin treatment causes weight loss and improves obesity-related symptoms in obese and insulin-resistant children 1. The investigators conducted a trial consisting of severely obese, insulin-resistant children aged 6 to 12 years assigned to random groups 1. The groups received either metformin or a placebo twice per day for 6 months and participated in a monthly dietitian-administered weight-reduction program. The results indicated that children prescribed metformin had significantly greater decreases in BMI, body weight and fat mass. Insulin resistance was also lower in metformin-treated children than in placebo-treated children. However, the researchers noted that gastrointestinal symptoms were significantly more prevalent in metformin-treated children, which limited dosage in some participants. The study concluded that metformin had modest but encouraging effects on body weight, body composition and glucose homeostasis.

Reported Side Effects

In another study investigating childhood obesity and the use of metformin, published in the November 2010 issue of the “World Journal of Pediatrics," researchers compared the effects of three types of drug regimens and a placebo on obese children and adolescents who did not lose weight months after lifestyle modification of diet and exercise. After the 12-week trial, the BMI of participants receiving metformin decreased significantly, whereas the decrease was not significant in the placebo group. Waist circumference also decreased significantly in the group receiving metformin, and no serious drug side-effects were reported.