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Is Belviq a Magic Wand for Weight Loss?

The new diet drug Belviq can help modestly with weight loss, but patients should be aware of dangerous complications and interactions.

Many of us are on a constant quest for an easy way to lose weight. Hope springs eternal, and in the spring plenty of us realize, as we contemplate donning shorts or even bathing suits, that winter has not been kind to us.

We may be looking for a way to drop those extra pounds. Losing weight is difficult, whether it’s 15 pounds or 50. That’s why weight loss drugs are appealing, even if the Food and Drug Administration says they are really only for obese people and not for those who are merely overweight.

Enter Belviq

The FDA approved lorcaserin (Belviq) in 2012, and it became available in 2013. You may be seeing ads for it now. They suggest that the pill will take away your appetite so that you can stick with a sensible diet and exercise program. The manufacturer admits,

“The precise way Belviq produces feelings of satisfaction is not fully understood.”

Does It Work?

The big question is efficacy: How well does it work? According to Consumer Reports, it can lead to weight loss of about 3 to 4 percent of body weight in a year. Now, that might be quite a few pounds for someone who meets the criteria for Belviq, with a body-mass index (BMI) of at least 30.

BMI is a way of determining obesity based on weight and height. A woman who is 5 feet, 6 inches tall and weighs 185 pounds has a BMI of 29.9. That means she is overweight, but she is not considered obese and wouldn’t qualify for a Belviq prescription unless she had other health problems.

How well does Belviq work? In two studies, subjects started at an average weight of 220 pounds. At the end of one year of treatment those on Belviq weighed 7.25 pounds less than those who had taken placebo. During the second year many of these subjects gained back some of the weight they had lost.

Are There Drawbacks?

What are the downsides of Belviq? Despite relatively modest benefit, there are side effects associated with this weight loss drug.

Serotonin Syndrome

Most worrisome, though rare, is serotonin syndrome. Belviq can trigger this condition, especially when people also take other medications such as cough remedies with dextromethorphan (DM), antidepressants, migraine medicines or even an herbal preparation such as St. John’s wort.


Symptoms of serotonin syndrome include anxiety, agitation, nausea, vomiting, hallucinations, uncontrollable muscle twitching, changes in blood pressure and heart rate, fever and loss of consciousness. It can be life threatening.

Other Side Effects

Other side effects of Belviq include headache, nausea, dizziness, fatigue, dry mouth and constipation. An unusually high rate of upper respiratory tract infections was reported during the clinical trials.

People with diabetes were also more likely to experience low blood sugar while taking Belviq.

The Takeaway

According to the experts at Consumer Reports, it would be safer to lose weight the old-fashioned way with diet and exercise.

Write Down Every Bite

Our recommendations include keeping a detailed food diary. Conscientious use of this technique has been shown to help people lose weight.

Watch Out for Flour and Sugar

There are also data suggesting that people can benefit by avoiding refined carbohydrates such as products made with white flour and sugar. Concentrating on low-starch vegetables, fruits, healthy fats and lean protein can also be helpful.

Our book, The People’s Pharmacy Quick & Handy Home Remedies, describes three scientifically proven diets (DASH diet, Mediterranean diet, and low-carb diet) that can be useful.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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