Orlistat for Weight Loss

Orlistat is a drug that is typically prescribed to treat obesity. It works by blocking some of the fat in your diet and prevents it from being absorbed by the body. It is also used to help you keep off weight that you may have already lost.

Orlistat weight loss drug - 120 mg strength
Orlistat 120 mg



Traditionally, Orlistat was only available by prescription. In 2007, the FDA approved Orlistat for over-the-counter sales. It was the first FDA approved weight loss product to hit the U.S. consumer market. It is sold over-the-counter at half of the prescription dose. Roche manufactures the prescription strength formula under the name Xenical.  The over-the-counter formula is sold under the trade name Alli.

How Orlistat works?

Orlistat is a lipase inhibitor that works by preventing fat absorption in the diet, thereby reducing caloric intake. It is typically prescribed by physicians to be used in conjunction with a supervised reduced-calorie diet and exercise program. Orlistat works by preventing triglycerides from being broken down in the intestines. In inhibits gastric and pancreatic lipases or enzymes from breaking down the triglycerides. Unprocessed fat and triglycerides are excreted from the body without being altered.

Orlistat Dosage

Prescription strength of this drug is 120 mg, taken three times a day prior to eating. At this dose about 30% of dietary fat is blocked from being absorbed. The over-the-counter dose is 60 mg which blocks about 25% of dietary fat from being absorbed. Higher doses have not been shown to have any additional fat absorption abilities. It should never be given to a child under the age of 12. It is not recommended for anyone under the age of 18.


Orlistat has proven effective at moderately reducing weight loss. Clinical trials suggest that taken in addition to diet and exercise can reduce weight by 4-6 pounds more per year than those not taking the medication. It’s effectiveness at reducing body fat varies from person to person. In one year clinical trials, 16-24% of people taking this medicine achieved a decrease in body fat of more than 10%. Another 35-54% of individuals achieved at least a 5% decrease in body mass. It has been shown to reduce the chances of developing type 2 diabetes and has been linked to a reduction in blood pressure. It is unclear if these decreases are due to Orlistat or due to the lifestyle changes that come along with a low fat diet and a long-term exercise plan.

Counterfeit Orlistat on the internet

In 2010, the FDA issued a warning that counterfeit Orlistat was being sold on the internet under the Alli label. This product was found to contain a different weight loss drug, Sibutramine. The concentration of this drug was over twice the recommended safe dose for weight-loss. They warned consumers that they should not purchase Orlistat or Alli online.


Orlistat has been shown to inhibit the absorption of fat-soluble vitamins and some fat-soluble nutrients. A vitamin supplement containing beta-carotene and vitamins A, D, E, and K should be taken once a day, at bedtime, while taking this medication. It should not be taken with certain other medications. It has a potential to reduce plasma levels of Ciclosporin which is an immune suppressant that is used frequently to prevent transplant rejection. Some research indicates that it may also reduce the effectiveness of some antiviral HIV medications. If you are taking any of these medications you should not begin taking this medicine. If you are currently taking Orlistat and you have been prescribed medication for one of these serious conditions you should discontinue using Orlistat. It should not be taken in conjunction with any other weight-loss products.

Side Effects of Orlistat

Orlistat does not have many side effects, but the ones it does have can provide severe discomfort to users. It works, in part, by using aversion therapy. Most consumers suffer from side effects when they begin treatment using this medication. Most side effects are gastrointestinal-related. They include loose oily stools and increased flatulence. Fecal incontinence and frequent and urgent bowel movements are often reported by users. This is due to unabsorbed fats entering the large intestine. It is designed to cause these effects in order to get users to reduce the fat content in their meals. The manufacturer recommends that consumers adopt a low-fat, reduced calorie diet while taking ths medicine. When dietary fat is reduced to below 15 grams per meal, the symptoms are much less severe. Alli clearly states on its packaging information that Olistat works by using this aversion therapy. Side effects are worse when first beginning treatment and decrease over time. It is believed that long-term dietary changes may have more to do with improved symptoms than adaptation to Orlistat does.

In 2010 the FDA approved a label revision stating that severe liver injury can be a side effect of using Orlistat. It is rare, but has been reported by individuals taking the prescription dose of the medication. A 2013 study of 94,695 Olistat consumers was published by the British Medical Journal. They did not find any evidence to support a higher incidence of liver damage associated with the product.

In a study which included 900 Orlistat users, the rate of acute kidney injury was more than triple that of those not taking the medication. The mechanism responsible for those these results may be due to an excessive oxalate absorption rate by the gut. This oxalate is then deposited in the kidneys, causing a buildup and subsequent kidney injury.


You should avoid taking Olistat if you have several conditions. You should use this product with caution if you suffer from obstructed bile ducts, impaired liver function or pancreatic disease. You should also avoid this product if you are under the age of 18. It should not be taken by individuals with type 1 or type 2 Diabetes, pancreatic disease, kidney problems, liver problems or those with under active thyroids. You should also avoid taking Orlistat if you are allergic to it or if you have had an allergic reaction to it in the past. You should not take this product if you suffer from Malnutrition or reduced gall bladder functioning. Orlistat should never be taken if you are pregnant or breastfeeding.

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