In a study done by Heather A. Hausenblas, PhD, and Brianna Huynh:
In the past decade, increased research and media attention has been given to the weight loss effects of green coffee bean extract (GCBE). The purpose of our study was to perform a review and meta-analysis of available randomized clinical trials examining the effects of GCBE supplementation on weight loss in both normal weight and overweight/obese individuals.
Results: The meta-analysis revealed a significantly larger weight loss effect for GCBE compared to placebo control. Analysis revealed a large effect size for GCBE with overweight/obese individuals on weight loss compared to a little to no effect for normal weight individuals with mild hypertension .