An experimental drug called tesofensine may have the potential to produce twice the weight loss of currently approved weight-loss drugs, according to a study published online in The Lancet.

In a phase II clinical trial involving 203 obese adults, investigators from the University of Copenhagen and their colleagues found that tesofensine was effective in producing weight loss due to reduced body fat. The trial participants were randomly assigned to receive either placebo or tesofensine at doses of 0.25 mg, 0.5 mg, or 1.0 mg once a day for 24 weeks. All participants who received tesofensine lost weight above that of placebo, and they also reported improvements in physical activity and self-esteem. Those who received 1.0 mg of tesofensine per day lost at average of over 20 pounds. However, in the 8 weeks following treatment, these same people experienced a 3.31% weight gain.

Currently available weight-loss drugs produce, on average, an additional 5 to 10 pound weight loss over that of diet and placebo over 6 months. For the increasing number of Americans who are overweight or obese, more effective medications are needed. Tesofensine seems like a promising drug, but phase III clinical trials are needed to confirm its safety and efficacy.