A university in Pennsylvania conducted a study on Keto Resources 16 overweight people ranging in age from 22 to 46, and had them alternate between receiving a green coffee bean extract called GCA in a high dosage of 1,050 mg, a low dosage of 700 mg, then a placebo, during treatment periods that lasted six weeks. The participants did not change their diet or exercise habits throughout the process, and furthermore did not take any other supplements, so as not to distort the results. 

On average, they lost 17 pounds, a fairly remarkable achievement, although the pool of participants was quite small. Along with body weight, significant body mass index reductions were also observed.As a phenolic compound, the chlorogenic acid contained in green coffee bean extract has also been connected to improved blood vessel action and circulation with a daily chlorogenic acid regimen of 140 mg, most likely due to the antioxidant and anti-inflammatory properties.

Although regular coffee drinking has been linked to beneficial effects such as increasing alertness or the effectiveness of pain medicine, coffee bean extract is actually taken in the form of pills, with two pills totaling 800 mg daily as the recommended dosage. The extract also only contains one fifth the amount of caffeine of brewed coffee.Interestingly, another study involving mice has concluded that chlorogenic acid in itself is only moderately effective in weight loss, whereas the green coffee bean extract actually produced better results, leading to speculation that the extract is preferable due to its ability to prevent fat absorption.