Xenical vs Alli

What is the difference between these two weight loss aids and which is the one for you?

Updated: Wednesday 27 April 2022

comparing xenical and alli

Xenical vs Alli

Both Xenical and Alli are two weight loss medications containing the same active ingredient, orlistat, so therefore they work in the same way. Both medications work by reducing the amount of fat absorbed into your body to help reduce our weight. Enzymes called lipase break down fat into smaller components that can be absorbed by the body however, Orlistat blocks this process to prevent some of the dietary fat being absorbed by the body and instead be released through bowel movements.

Although both medications work in the same way, they are some key differences between them. Alli contains 60mg of Orlistat, whereas Xenical contains 120mg. Since Xenical contains double the dose of Orlistat than Alli, the results tend to be seen faster, as long as the treatment is combined with a reduced calorie, low-fat diet and regular exercise.

The following table compares the differences between the two medications.

  Alli Xenical
  Alli Xenical
Active Ingredient Orlistat Orlistat
Strength 60mg 120mg
Suitability BMI = 28 BMI = 30
Directions One capsule three times a day with meals One capsule three times a day with meals
Legal Classification P - Available from pharmacy counter POM - Prescription only medication
Price From £29.99 for 84 capsules (1 month supply) From £68.99 for 84 capsules (1 month supply)

Side effects

Like all medications, both Xenical and Alli cause side effects, but not everyone gets them. The side effects of both medications are very similar, the most common ones include:

So which treatment is more effective?

Both Alli and Xenical are effective if used alongside a well-balanced calorie-controlled diet with an exercise programme. Your decision as to which medication you should choose should be based primarily on your BMI (Body Mass Index). The NHS provides a handy tool to calculate your BMI quickly. If your BMI is 30 or greater and you have the option to take either Alli or Xenical then Xenical may be the more effective option for reducing your weight quickly.

It is important to note that Xenical is also available as a generic medication, Orlistat 120mg, which is medically equivalent to the brand Xenical and so would be an equally effective option and is slightly cheaper. Prices start at £39.99 for 84 capsules (1-month supply) for Orlistat.

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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How Does Orlistat Work & What Makes It Effective?
How Does Orlistat Work & What Makes It Effective?