How effective is Orlistat?

Orlistat is a weight loss medication suitable for those with a high body mass index. But how effective is it?

Updated: Thursday 15 April 2021


orlistat weight loss

Orlistat is a medication that is used to help with weight loss suitable for those with a body mass index (BMI) greater or equal to 30 kg/m², or overweight patients (BMI > 28 kg/m²) with associated risk factors such as high blood pressure, high cholesterol and diabetes. It is extremely effective when used correctly and it is therefore essential that you understand how it works before you start using it to make sure it is suitable for you and that you get the best out of your medication.

How does Orlistat work?

Normally, when fat is consumed gastric and pancreatic lipases, that is, enzymes in the stomach and small intestine, break down fat into smaller molecules which then allows it to be absorbed into the bloodstream. Orlistat works by interfering with the enzymes that break down fat and stops them from working. This means that fat consumed in your diet cannot be absorbed into the bloodstream and is consequently passed out through your body unchanged, therefore helping you to lose weight.

Orlistat can only prevent absorption of about one third of the fat consumed by a person so it is important that you also try and reduce your fat intake as well as improving your diet on the whole and increase exercise. As Orlistat works on fat digestion, if a meal is missed, or no fat is consumed in that meal, the medication will not work and so the dose of Orlistat should be missed.

How effective is Orlistat?

Orlistat has proven effectiveness when used correctly and clinical studies have found that Orlistat will help you to lose 50% more weight than if you were dieting alone. Results can be seen quite quickly; trials have shown an increase in fat being passed out the body as early as 24 to 48 hours after starting the medication.

Where people go wrong is when they rely on Orlistat to do all the work and do not make any other lifestyle changes. It is critical that it is used in conjunction with a carefully balanced nutrient-rich calorie-controlled diet plan and increasing regular exercise. Orlistat reduces absorption of approximately 30% of dietary fat consumed, so to get the best out of the medication it is essential that a low-fat diet is consumed. It is also recommended that your diet is rich in fruit and vegetables and that your daily intake of protein, carbohydrate and fat is distributed equally over your three main meals.

Iris Barbier

Written by: Iris Barbier

Pharmacy Assistant

Born in France, Iris moved to the UK to study Biological Sciences at London Metropolitan University. Upon graduating, Iris moved up north, where she completed an MA in Science Journalism at the University of Lincoln.

As a qualified science journalist, Iris uses her expertise to write content for Pharmica’s online Health Centre. She ensures our patients get specialist knowledge on medical conditions and how to treat them.


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