How Does Xenical Work?

Xenical works by partially blocking the absorption of fat. In combination with a low-fat diet, it can assist with weight loss. 


In the United States, since the early 1960s obesity rates among adults have more than doubled.

Currently an estimated 35.7% of American adults age 20 and older are obese. According to the 2009-2010 National Health and Nutrition Examination Survey, more than two-thirds of American adults are considered overweight or obese and more than 5% of adults are considered to have extreme obesity. Prevalence of obesity is about the same for men and women.

Black and Hispanic people have a higher incidence of weight problems, with over three-fourths of these populations considered overweight or obese. Extreme obesity is more prevalent in blacks than in non-Hispanic whites, while whites have slightly higher extreme obesity rates than Hispanics. Only 11.6% of Asian Americans are overweight or obese, with rates among Native Americans at 39.9% and 43.5% for Native Hawaiians and other Pacific Islanders.

Excess weight is caused by an energy imbalance, where the body takes in more energy in the form of food than it expends through metabolism and activity. Losing excess weight and keeping it off can be tremendously challenging, and some people take prescription medications like Xenical to help them lose weight.

History of Xenical

Xenical is the brand name for a drug called orlistat. It was approved by the U.S. Food and Drug Administration at a dosage of 120 mg in the year 1999. The drug is approved for obesity management and to lower the risk of regaining weight after weight loss. Xenical was designed to be taken by people who are considered obese, that is, those who are at least 30% heavier than their ideal weight or who have a body mass index (BMI) of 30 or higher. It is also prescribed for people who are at least 20% over their ideal weight (with BMI 27 or greater) and who have other health risk factors like high blood pressure, diabetes, or high cholesterol levels. If you’re unsure what your BMI is, the National Institutes of Health offers an online calculator here.

How Xenical Works

When most people think of diet pills they think of stimulants, but that’s not how Xenical works. Rather, Xenical is known as a lipase inhibitor. It prevents your body from breaking down and absorbing the fats in foods. Around 30% of the fat eaten in a meal goes through the digestive system unabsorbed when people take Xenical. When insufficient calories from food are absorbed, the body must use its own fat stores for energy, and the result is weight loss.

That unabsorbed fat has to go somewhere, and that somewhere, to put it bluntly, is the toilet. Because Xenical lets fats go through the digestive system unabsorbed, people taking in can experience diarrhea or anal leakage when they consume foods high in fat. But that’s part of the genius of Xenical: it not only causes your body to absorb less fat from foods, it encourages you to eat low-fat foods so as to minimize unpleasant side effects. Xenical plus a balanced, low-fat diet equals greater weight loss than cutting calories alone.

What Clinical Studies Say About Xenical

Clinical studies with Xenical found that when the medication was taken along with a balanced, low-fat diet, average weight loss was twice that of people who took a placebo and maintained a balanced, low-fat diet. What’s more, those who took Xenical maintained weight loss better than people did on a placebo with the weight maintenance diet. After four years of treatment, only 28% of placebo-plus-diet patients lost more than 5% of their body weight, while 45% of Xenical patients lost 5% or more of their body weight.

Xenical’s effects went beyond pounds lost, however. When patients were studied for risk factors like fasting glucose, HbA1c (a longer term indicator of glucose control), blood pressure, and cholesterol levels, risk factors were lower in study groups taking Xenical compared with those taking a placebo. In the first year of taking Xenical and maintaining a low-fat diet, patients lost weight faster and lost more of it than did patients who consumed a placebo along with their low-fat diet.

Taking Xenical Safely

Success with Xenical requires eating a low-fat diet.


Xenical should be used in conjunction with a reduced calorie diet that has no more than 30% of its calories from fats. This will not only help with weight loss, but will help reduce side effects. Xenical does interfere with the body’s absorption of certain fat-soluble vitamins, so people taking Xenical should take a daily multivitamin supplement containing beta carotene as well as vitamins D, E, K, and A. Vitamins should be taken once a day, at least two hours before or after taking Xenical.

Why Xenical Is a Top Pick for Weight Loss

There aren’t that many choices in prescription weight loss drugs, and most weight loss drugs rely on a stimulant effect to cause the body to burn more calories than usual. Stimulant weight loss drugs should generally not be used long term. The safety of Xenical, however, has been studied for periods of up to 4 years, and Xenical is the only prescription weight loss drug approved for long term use.

Xenical is not a controlled substance, but other prescription weight loss medications are, including Adipex-P and Suprenza (which are brand names for phentermine), Belviq, Bontril, Desoxyn, Didrex, Diethylproprion, and Qsimia.

Xenical can be obtained safely online if you know what to look for in a provider. Look for businesses with a verifiable US street address (not just a P.O. Box), and a phone number with a matching area code (in addition to any toll-free customer service lines). Make sure you only order from providers that require a prescription, because Xenical is a prescription drug. Providers that claim not to need a prescription are most likely selling counterfeit products, which could be dangerous.


At, we have provided over half a million satisfied customers with name brand prescription medications like Xenical for over 15 years. With friendly and helpful customer service, often ships orders the same day they’re received, so your products arrive quickly via trusted delivery services like FedEx. And we are thoroughly committed to patient privacy and the highest standards for online ordering security.

Generic Viagra, Cialis or Propecia