GCE is a supplement made from green unroasted coffee beans. The supplement is available in capsule form, or it can be added to beverage products or chewing gum. The supplement contains naturally occurring caffeine and chlorogenic acid, a polyphenol antioxidant. Green coffee is used because the roasting process of coffee beans reduces the chlorogenic acid levels. The theory behind this product is that the chlorogenic acid is thought to be responsible for several of its pharmacological effects in GCE. It has been shown to inhibit fat accumulation and reduce weight in animal models and humans. In addition, GCE is thought to reduce postprandial glucose concentrations. It is also thought to reduce glucose absorption in the intestine.