Alli is serious weight loss medicine, designed for adults 18 years or older. Alli is the only FDA approved, over-the-counter weight loss product that works by preventing your body from absorbing some of the fat you eat. But Alli is more than just a pill. It's an innovative weight loss program that includes an individually tailored, online action plan to help you lose weight safely and gradually. By following this personalized plan, and using Alli only as directed you may be able to lose about 50% more weight than with just dieting alone. That means if you could lose 10 pounds through dieting, you could lose 15 with alli. As with all medications, Alli has potential treatment effects, the most common of which are bowel changes that may include gas with oily spotting; loose stools and more frequent stools that may be hard to control. For complete information, read all the package information and follow instructions carefully. Use of Alli can also effect some vitamin absorption, so you should take a multivitamin daily while taking alli capsules.