Orlistat (Alli) is the popular drug, developed by pharmaceutical giant Roche, to treat obesity. Orlistat is probably more recognizable under its marketed names of Xenical or the over-the-counter drug, Alli. Orlistat’s primary objective is to prevent the absorption of fat that is consumed and thereby reduce caloric intake and ultimately body weight.

Orlistat works by inhibiting the pancreatic enzyme, lipase, which is responsible for metabolizing triglycerides in the intestine. Triglycerides are a fancy name for a kind of fat that is found in vegetable oils and animal fats. Without the enzyme lipase, triglycerides are not absorbed and are instead excreted from the body. The prescription form of Orlistat is given to overweight people that also have accompanying conditions of high blood pressure, Type 2 diabetes, high cholesterol or heart diease. Orlistat is also used after weight loss to help people prevent gaining back the weight lost.

There are uncomfortable gastrointestinal side effects that come with taking Orlistat. In addition, Orlistat’s weight loss effects are modest. Those taking Xenical, the prescription form of Orlistat, lost on average about six pounds more than those who just relied on diet and exercise alone during a one-year time frame. Taking the over-the-counter drug Alli results in an average of three pounds greater loss than just relying on diet and exercise alone within a one-year time frame.


  • Taking Orlistat correctly, can reduce weight
  • The FDA has approved Orlistat
  • The active ingredient in FDA-approved Xenical and Alli
  • Published studies proving results
  • Thorough dietary guidance


  • There is no magic pill to weight loss
  • Orlistat has many gastrointestinal side effects
  • Orlistat may not be a long-term weight loss solution
  • Weight loss is modest
  • Must continue to take weight loss medication in order to keep weight off


Orlistat contains a saturated form of lipstatin, a powerful natural inhibitor of lipase, the pancreatic enzyem that absorbs fat.  


Orlistat is taken in a capsule form three times a day with a meal that contains fat. If the meal does not contain fat, then you should not take Orlistat.

At the standard prescription dose of 120mg, three times daily before meals, Orlistat prevents approximately 30% of dietary fat from being absorbed. Over-the-counter dosages, like the product Alli, contain 60mg of Orlistat. This amount prevents about 25% of dietary fat from being absorbed.Taking more Orlistat than the standard 120mg does not accelerate weight loss.


Orlistat is always used in combination with a physician-monitored reduced-calorie and low-fat diet as well as regular exercise program.

You should also not consume foods that contain more than 30% of their calories from fat. This will increase the chances of experiencing gastrointestinal side effects. While taking Orlistat, each meal that you eat should contain 15 grams of fat or less.  It is recommended to eat 2-3 ounces of lean protein with each meal as well as filling your plate with good carbohydrates like vegetables and whole grains. Low-fat or fat-free versions of dairy and salad dressings should be eaten as well as asking for foods to be prepared without fat when dining out.

Since Orlistat also inhibits the absorption of the fat-soluble vitamins, A, D, E and K, a multivitamin that also contains beta-carotene must be taken on a daily basis, preferably at bedtime or two hours after taking Orlistat, to ensure that your body is readily absorbing these necessary nutrients.


Orlistat is one of the only FDA-approved weight loss drugs. Even though it may help those who are overweight or obese to lose weight, it does carry some serious side effects. In addition, those who stop using the drug typically regain the weight back within a few months.

Since Orlistat also contains many contraindications, it is necessary to talk with your doctor before taking any form of Orlistat.