by Dr Deborah Lee, Dr Fox Online Pharmacy
Image by Bruno /Germany from Pixabay
What is Xenical (Orlistat)?
Orlistat is a type of medication used to treat obesity. It can also help prevent the weight from being regained after a weight loss diet has been completed.
The proper medical name for Orlistat is tetrahydrolipstatin. It is sold under the brand name, Xenical, and also as a lower-dose product, Alli. Both products contain the same active ingredient – Orlistat.
How does Xenical (Orlistat) cause weight loss?
Orlistat works by blocking the actions of gastric and pancreatic lipases – these are enzymes which break down fat into triglycerides and free fatty acids, which are then absorbed into the bloodstream through the gut wall. When lipase enzymes are inactivated, fat cannot be absorbed and passes on through the intestines to be excreted in the stools.
Orlistat works locally within the gut wall, and only a tiny amount is absorbed into the bloodstream, reducing the risk of systemic side effects. When taken at the recommended dosages Orlistat prevents about 30% of dietary fat from being absorbed. Some fat absorption is necessary because some vitamins are fat soluble.
Research has shown that Orlistat has other advantages as it seems to be beneficial for carbohydrate metabolism. Orlistat results in weight loss and is also associated with a slight reduction in blood pressure. It also tends to lower uric acid levels so may reduce attacks of gout.
How to take it?
One capsule, 120 mg of Orlistat is taken three times a day, just before mealtimes or within one hour of eating. At this dose, Orlistat is reducing your calorie consumption by around 200 calories per day.
Orlistat should only be taken with meals that contain less than 30% fat. Because Orlistat works by inhibiting the breakdown and absorption of dietary fat, there is no point in taking them with a fat-free meal. Equally, they should not be taken with a high-fat meal, as this can result in unpleasant gastrointestinal side effects such as foul, orange-coloured diarrhoea.
The product Alli contains the same constituents as Orlistat but at a lower dose of 60 mg per capsule. It is taken in the same way as Orlistat. Alli can be purchased over the counter without a doctor’s prescription.
How effective is Xenical (Orlistat) at causing weight loss?
Xenical (Orlistat) has been found to be more effective than a placebo in aiding weight loss.
- In a 2002 randomised, placebo-controlled trial of 531 obese patients, after 54 weeks, weight loss was significantly greater in the Orlistat than in the placebo group. The Orlistat group lost an average of 5.8% of their body weight whereas the placebo group lost 2.3%. In addition, the Orlistat group were found to have a greater reduction in systolic and diastolic blood pressure, total and LDL cholesterol, glucose tolerance, and waist circumference measurements.
- In a 2006 randomised placebo-controlled trial of 391 overweight participants, the Orlistat group lost an average of 4.1kg compared to the placebo group who lost 3.1kg and this difference was statistically significant. The Orlistat group were also found to have a greater reduction in total and LDL cholesterol and in systolic and diastolic blood pressure.
- In a 2004 meta-analysis, the authors reviewed 23 clinical trials and concluded that Orlistat was significantly effective in inducing weight loss and reducing obesity-related risk factors.
- In a 2012 study, 131 subjects with a BMI of 25-34.9 were randomly assigned to Orlistat 60 mg, three times a day, or a placebo, and asked to follow a low-calorie, 30% fat diet, and walk for 45 minutes, five times a week. At 24 weeks there was a statistically significantly greater loss of visceral fat in the Orlistat group than in the placebo group. They also demonstrated greater weight loss – an average of 5.63 Kg as compared to 3.94 Kg – and a greater reduction in liver fat.
Overall, Orlistat when taken with a low-calorie diet, and with an increase in physical exercise, is an effective way to aid weight loss. It also has other health benefits such as lowering systolic and diastolic blood pressure, improving the lipid (cholesterol) profile, and helping get rid of visceral fat, with a consequent reduction in waist circumference.
What are the side effects?
Orlistat works in the gut. It is broken down in the gut wall, and the breakdown products are excreted in the stools. Very little is absorbed into the bloodstream. Hence, any side effects are generally local, and gut-related, rather than systemic.
It can cause loose greasy stools, with diarrhoea, bloating and flatulence. These side effects are minimized by keeping the fat content of the diet under 30%. If these effects occur, they tend to improve over the first 4 weeks.
Use of Orlistat could lead to possible vitamin deficiencies of the fat-soluble vitamins – A, D, E and K. For this reason, those on Orlistat are asked to take vitamin supplements.
There have been concerns about Orlistat and possible liver toxicity, however, these are largely unsubstantiated, and if there is a risk, this is small. Obesity itself is associated with liver damage, and when liver abnormalities are reported in the first 30 days of Orlistat usage, these may well have been present before Orlistat was started and are felt to be unlikely to be due to a specific effect of the drug.
Orlistat allergy has been reported rarely, and this may be associated with liver disease.
In fact, studies show that Orlistat often leads to improvement in nonalcoholic fatty liver disease (NAFLD).
Who is suitable?
To be eligible for Xenical (Orlistat) you need to have a BMI of 30 or above or a BMI of 28 plus a medical condition that would be improved by weight loss such as high blood pressure or type 2 diabetes.
You will need to be weighed and measured regularly and will be expected to lose 5% of your body weight in 3 months. If not, the Orlistat will be stopped.
When taking Orlistat, you need to plan your meals and keep the fat content of each meal below 30%. You also need to keep exercising and doing at least 150 minutes a week of moderate-intensity exercise such as brisk walking, jogging, cycling to swimming. This can be done in short intervals, for example, 3 x 10-minute brisk walks every day.
Who should not take it?
You should not take Orlistat if you have any of the following
- Allergy to Orlistat
- Chronic malabsorption
- Cholestasis (reduced flow of bile)
- Eating disorders such as anorexia or bulimia
- Severe kidney disease – renal failure
- Pregnancy and breastfeeding
Drug interactions
Drugs which are lipid soluble may not be well absorbed when taking Orlistat. Care must be taken with drugs such as antiepileptics, amiodarone, thyroxine, warfarin and anti-HIV drugs. Diabetics need to monitor their blood sugars more often and be aware that Orlistat can affect their glucose levels. Your GP will advise you.
Where to obtain Xenical (Orlistat)
You can obtain Orlistat from
- Your GP – via an NHS prescription.
- An online pharmacy.
Final thoughts
Losing weight is hard, and so many of us have tried and failed. Sometimes we all need a boost, and Orlistat seems to do just that. We know that using weight loss drugs plus undertaking lifestyle changes results in better weight loss than dieting alone. Taking a drug such as Xenical (Orlistat) for a year typically results in a loss of between 3-12% of body weight. If you are serious about losing weight, Orlistat is a good option as it works locally in the intestines with almost no systemic absorption. Although reports of using it are mixed, many are very positive about using it. The trick has to be to keep your dietary fat intake low, and t keep exercising.
Could Xenical (Orlistat) help you on your weight loss journey?