Amsa Fast or  Orlistat blocks some of the fat that you eat, keeping it from being absorbed by your body.   Orlistat is used together with a reduced-calorie diet and weight maintenance to treat obesity in people with certain risk factors (such as diabetes, high blood pressure, and high cholesterol or triglycerides).  Orlistat may also be used for purposes other than those listed in this medication guide. Ref:   obesity, sustainable weight loss.  Lab Pisa