alli (orlistat 60 milligram capsules) is your smart edge for weight loss. Among weight loss products, it's the only FDA-approved over-the-counter weight loss aid. Orlistat, the active ingredient in alli, is a lipase inhibitor and works by binding to specific enzymes that break down fats. As a result, about 25 percent of the fat you consume is not absorbed and passes through the digestive system. Since the calories associated with this unabsorbed fat are not used, the number of calories that enter your system is reduced. You're ready with alli by your side. alli (orlistat 60 milligram capsules) is a weight loss aid for overweight adults, 18 years and older, when used along with a reduced-calorie and low-fat diet. Read and follow label directions.