Most weight loss pills work by suppressing the appetite in some way. This is often done by changing the chemicals in the brain to make the body feel full or reduce the positive feelings that come from eating. Xenical, on the other hand, is a weight loss option that has no effect on the brain. Instead, Xenical works in the digestive system. In your digestive system there are enzymes, known as lipases, which help break down the fat that you eat so that your body can absorb it. Without lipases, fat would pass through the digestive tract and be expelled when you had a bowel movement. Xenical has an ingredient in it that bonds to some of the lipases in your body and keeps them from allowing the fat to be absorbed into your body. As a result, the fat is expelled when you have a bowel movement instead of being absorbed by your body and added to your already growing deposits of fat. Since some fat is necessary for healthy living, Xenical only blocks about one-third of the fat you consume from being absorbed into your body.

Xenical is highly effective at blocking the absorption of some fat. However, this alone is not sufficient for weight loss. Simply blocking the absorption of fat may keep you from gaining more weight, but it will not cause you to lose the weight you have already gained. This requires a reduced calorie diet and exercise, and adding Xenical to the equation can help you lose more weight.

Xenical, combined with a diet low in fat, is highly effective as a weight loss solution. In a clinical study that followed obese patients for over a year, researchers found that those who took Xenical along with a low fat diet lost twice as much weight as those who only dieted. Patients who have a body mass index of 30 or higher are good candidates for this medication. Also, those with lower body mass indexes who have other risk factors, such as hypertension, could benefit from adding Xenical to their weight loss plans. Other than changes to your bowel movements, which can sometimes be embarrassing, there are few risks or side effects known with the use of Xenical. Some vitamins from your food are not absorbed as well when you take Xenical, so you should take a vitamin supplement containing A, D, E and K whilst you are on this medication.