“You may think magic is make-believe, but this little bean has scientists saying they’ve found a magic weight-loss cure for everybody,” said Dr. Mehmet Oz in 2012. Then sales of the green coffee bean extract skyrocketed.

When consumed in moderation, coffee may have a positive effect on our health. In fact, epidemiological studies show that moderate coffee drinking can reduce the risk of developing certain chronic diseases. Even decaffeinated coffee aids in good health. So if it’s not the caffeine, then what makes java healthful?

Enter the polyphenols, a family of plant compounds rich in antioxidants. Various studies suggest that polyphenols found in coffee beans have health benefits such as inhibiting high blood sugar. A 2012 study, published in Diabetes, Metabolic Syndrome and Obesity, focused on the link between green coffee beans (unroasted seeds) and weight-loss. Researchers studied the effects of chlorogenic acid (CGA), one of the natural coffee compounds, and found a potential link between CGA and body fat reduction.

Joe Vinson, Ph.D., professor of chemistry at the University of Scranton, led the 22-week study. Successful participants who received Green Coffee Antioxidant (GCA®) had an average of 16% body fat reduction.

Does this mean we’ve found a magic pill to end obesity? When looked at carefully, the study has a few methodological issues, including a small sample size – 16 adults. Moreover, Applied Food Sciences, the company that makes green coffee antioxidant supplements, funded the study. So Dr. Oz conducted his own experiment. In two weeks, the 50 women who took a daily supplement lost an average of two pounds, while participants who took the placebo lost an average of 1 pound. Despite the non-dramatic results, Dr. Oz still stands behind the extract, and recommends capsules that contain at least 45% chlorogenic acid.

Of course, conventional coffee contains CGA too. Then why spend the extra cash? See, when coffee beans are roasted, CGA levels decrease. That’s why green coffee bean promoters recommend the supplements. Keep in mind, however, that they’re not regulated and not enough studies have been conducted to rule out possible adverse effects.

In the spring of 2013, a study published in the Journal of Agricultural and Food Chemistry didn’t support weight loss associated with CGA consumption. Compared to normal diet fed mice, the high-fat diet and high-fat diet supplemented with CGA mice gained more weight. Although body weight increase didn’t differ between the two high-fat diet groups, fatty deposits accumulated in the livers of mice who were on the supplemented diet. These little creatures had higher blood sugar levels too. It should be noted that the study used a higher dose of CGA compared to studies that claimed chlorogenic acid reduced weight gain in high-fat diet mice.

If you still want to try the green coffee bean, the Dr. Oz show recommends you look for brands that don’t contain fillers or artificial ingredients.

“When looking for a green coffee supplement, it should contain the chlorogenic acid extract, which can be listed as any of the following: GCA® or Svetol®,” states the Fact Sheet on Dr. Oz’s official website.

Just like with all supplements, consult your physician before starting this diet program. But don’t expect a magic bean that’ll allow you to make bad food choices and still shed pounds. A low-fat diet, rich in fruits and vegetables, can ward off diseases. And a healthy diet in combination with regular exercise can keep obesity away.