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You don’t have to be a registered dietitian to know that eating healthy and working out are clutch for losing weight. But that doesn’t mean there aren't a lot of people still hoping a medicine or supplement will be invented to make dropping pounds as easy as popping a pill.
Enter: Orlistat, the active ingredient found in weight-loss medications like Xenical and Alli. These drugs are intended to help people who are obese and overweight lose weight by taking a pill with every meal, while on a reduced-calorie meal plan.
Sounds pretty simple, but does this medication actually work? Here’s what you need to know about the side effects and its safety.
1. It can be prescribed or bought over-the-counter.
In 2007 the FDA approved Xenical, which contains 120 miligrams of orlistat and must be prescribed. Alli, an over-the-counter option containing 60 miligrams of orlistat, was also approved by the FDA that year. No matter what med you choose, you take one capsule before, during, or after each of your three daily meals so it can act on the food you’re eating, according to FDA's website.
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2. The drug works by stopping the absorption of some fat in your diet.
Orlistat acts in your gut, stopping enzymes that break down fats from doing their job properly, says Deena Adimoolam, M.D., Assistant Professor of Diabetes, Endocrinology and Bone Disease, Icahn School of Medicine at Mount Sinai. Specifically, it inhibits pancreatic lipase, meaning fats can pass undigested through the body, reducing the number of calories you absorb. When you take an orlistat-based med with a meal, about 30 percent of the fat you consume won’t be broken down in your gut. Instead, it is eliminated through bowel movements (basically, you poop it out). That means people taking orlistat should eat a low-fat diet, since any extra fat you consume will just… uh… find its way out.
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3. The side effects seem pretty gnarly.
Primary side effects include oily, loose stools, excessive flatulence, fecal incontinence, anal leakage (a.k.a. oily spots in your undies), and frequent or urgent bowel movements, especially if you’ve eaten high-fat or oily foods, according to the FDA. Other potential side effects include severe liver injury. Yeah, not the best.
“Some of these gastrointestinal side effects can be limited by avoiding high-fat diets and sticking to the recommended intake of no more than 30 percent fat,” says Adimoolam. (Speed up your progress towards your weight-loss goals with Women's Health's Look Better Naked DVD.)
4. It’s been shown to help users lose a bit of weight.
“In many clinical trials orlistat has shown to be more effective with weight loss than… lifestyle [or a] placebo,” Adimoolam says. “Some research studies suggest that the average weight loss associated with orlistat is roughly 5.3 kg (11.68lbs) over one year [or more] of treatment.”
That said, you’ve got to stick to the plan: Follow a low-fat, low-calorie meal plan, and exercise regularly.
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5. It’s not necessarily dangerous, but there are times when you should avoid taking it.
“Orlistat should be avoided in people with intestinal issues, especially those who are prone to malabsorption of fats due to intestinal surgeries, diseases affecting the pancreas, etc.,” says Adimoolam.
Adimoolam also recommends that you don’t take orlistat if you are trying to conceive or have a history of kidney stones. And, she says users should keep an eye on their vitamin levels: “Orlistat may decrease the absorption of fat soluble vitamins, like vitamin A, D, E and K. People taking orlistat should be monitored for Vitamin D deficiency.”