What is Alli?

Alli is a 60-milligram, over-the-counter version of orlistat (Xenical), a 120-milligram prescription drug. Both Alli and Xenical are meant to be used as part of a weight-loss plan, along with a low-calorie, low-fat diet and regular physical activity.

Alli is approved by the U.S. Food and Drug Administration for use in adults 18 and older who have a body mass index (BMI) of 25 or more. Xenical is approved for use in adults with a BMI of 30 or more (obese). Xenical is also approved for those with a BMI of 27 to 30 (overweight) who have other health risk factors such as high blood pressure or diabetes.