Green coffee extract is an extract of unroasted, green coffee beans. Green coffee extract has been used as a weight-loss supplement and as an ingredient in other weight-loss products. Its efficacy and mechanism of action have been the subject of controversy.
There is tentative evidence of benefit; however, the quality of the evidence is poor. In 2014 one of the primary trials showing benefit was retracted and the company that sponsored the study, Applied Food Sciences, was fined by the Federal Trade Commission for making baseless weight-loss claims using the flawed study.
Green coffee extract is sold under various proprietary brand names including Svetol, and is included in weight-loss products such as CoffeeSlender.
A 2011 review found tentative evidence that green coffee extract promotes weight loss; however, the quality of the evidence was poor. This review looked at three published randomized controlled trials of green coffee extract, totaling 142 participants, and found a small effect. The review stated that more rigorous trials with longer duration were needed to assess the efficacy and safety of green coffee as a weight loss supplement. Participants in the studies were instructed to restrict their diet and increase their exercise in addition to taking the supplement.
One of the trials was retracted in 2014 because the accuracy of the data was unclear.
The three clinical trials reported no adverse events; however the review noted that two participants in an unrelated non-trial study report dropped out due to adverse events including headache and urinary tract infection.