alli Diet Weight Loss Supplement Pills, Orlistat 60Mg Capsules, 170 Count Alli is an FDA-approved weight loss supplement designed to help block about 25% of the fat you consume from being absorbed by your body. It works as an effective weight loss aid for both men and women. For every 5 pounds you lose through diet and exercise, alli can help you shed an additional 2 to 3 pounds. The supplement works in the digestive system and is only minimally absorbed into the bloodstream, meaning it doesn't have a direct impact on your heart or nervous system. Alli is intended for overweight adults aged 18 and older, and is most effective when combined with a reduced-calorie, low-fat diet.