If you’re looking for a weight-loss miracle, you might think you’ve found it when you read about green coffee extract (GCE). GCE is popping up in ads all over the Internet. It even has its own Facebook page.

This diet supplement is marketed as a quick and easy way to burn fat and shed those extra pounds without changing your diet or eating habits — and with no exercise. "The fat just falls away!" Does it really work? If so, where’s the evidence, and most importantly, is it safe?

A green coffee bean is simply an unroasted coffee bean. Green coffee supplements contain naturally-occurring caffeine and an antioxidant called chlorogenic acid. The supplements are made from the unroasted coffee beans because roasting decreases the amount of chlorogenic acid. GCE can be purchased in capsule form, added to chewing gum or mints, or used as an ingredient in beverages.

The supplements are made from the unroasted (green) coffee beans because roasting decreases the amount of chlorogenic acid.

Researchers theorize that chlorogenic acid may be responsible for the pharmacological effects of GCE. Studies have shown that chlorogenic acid may inhibit fat accumulation causing weight-loss in both animals and humans. And it may reduce glucose concentrations after eating, and reduce the absorption of glucose in the small intestine. There is speculation that GCE could alter the level of adipokines, hormones that are involved in fat distribution and energy usage by the body.

What the Studies Found

In 2011, a review or meta-analysis of a number of research studies on the effectiveness of GCE for weight-loss was published in Gastroenterology Research and Practice. The reviewers concluded that while the results of the studies showed promise, the methodology of many of the studies was poor. Moreover, an author of one of the studies reviewed had received funding from a company that manufactures green coffee extract.

People with medical conditions such as anxiety disorders, bleeding disorders, diabetes, glaucoma, high blood pressure, irritable bowel syndrome, and osteoporosis may be adversely affected by GCE.

A small study on GCE created quite a buzz in early 2012. In this crossover study, 16 overweight participants took a high dose of GCE (1,050 mg), a low dose (700 mg), or placebo for six weeks. The average weight-loss was 18 pounds over 12 weeks. The authors of the study stated that they could not explain the mechanism which caused the weight-loss, but they theorized that GCE alters both carbohydrate and fat metabolism causing fewer calories to be absorbed.

Then Dr. Oz conducted his now-famous "made-for-TV clinical trial" on GCE. The audience for this television episode was filled with the 100 overweight women who participated in the study. Some were given a placebo while others took a 400 mg GCE supplement three times a day. The women who took the supplement lost an average of two pounds in two weeks. Those who took the placebo lost one pound. Dr. Oz called it a "miracle" and claimed GCE was a "fat-burner."

What Consumers Say

If consumer reviews are any evidence of the effectiveness of GCE, then the supplement doesn’t live up to its reputation. On one website selling the product, most of the people who purchased the supplement reported they were disappointed with the lack of results, though many said they had more energy, presumably due to the effect of the caffeine. It should be said that such anecdotal evidence is not proof of GCE's effectiveness or ineffectiveness.

So, does green coffee extract work for weight-loss? At this time there just isn’t a clear answer. The evidence is pretty sketchy. The studies that have been done haven’t been good studies, so much more research is needed. None of the studies has determined an optimal dose, and formulations can differ from one brand of the supplement to another.

Safety Is an Issue, Too

Is green coffee extract safe to try? Probably, but certain people should avoid the supplement. High doses of caffeine can cause adverse reactions ranging from headaches to anxiety to irregular heart rhythm. Taking GCE with other dietary supplements that contain caffeine can cause dangerous interactions. High doses of caffeine can also trigger the loss of calcium and magnesium from the body. It is also worth noting that since the GCE supplements are unregulated, there is no guarantee how much of a dose one is receiving.

Caffeine can have adverse interactions with certain prescription drugs, and the list of such drugs is a long one. In addition, people with medical conditions such as anxiety disorders, bleeding disorders, diabetes, glaucoma, high blood pressure, irritable bowel syndrome, and osteoporosis may be adversely affected by GCE.

According to a recent article in the Journal of the Academy of Nutrition and Dietetics, "The evidence on the use of dietary supplements for weight loss indicates little to support use in the management of overweight and obesity. Treatment for overweight and obesity continues to evolve. A healthful lifestyle that includes increased physical activity, reduced total energy intake, and behavior therapy is the foundation of a comprehensive weight management program."

A month’s supply of GCE costs about $30. For a person who is trying to lose weight, that money may be better spent on weight loss strategies that are proven to work, such as a gym membership, exercise class, or fresh fruits and vegetables. There is just too much that is unknown about GCE.