Orlistat is a weight loss medication used to help reduce your BMI. It has been proven to be effective in treating obese and overweight patients and helping them to lose weight. In this article, we discuss what you can do to get the best results while taking it.

Order Orlistat online from 39p per capsule


Orlistat has been proven to be a safe and effective weight loss treatment. It is only used in people with a body mass index (BMI) of 30 or more, or a BMI of 28 or more if they have weight-related risk factors like type 2 diabetes and high blood pressure. 

It is also known by the brand name Xenical and the over-the-counter version Alli. Alli is available as a brand of orlistat in UK pharmacies. The active ingredient for both products is orlistat. The prescription-strength orlistat is 120mg, which is double the strength of Alli.

Orlistat works by blocking the fat you eat from being digested. The fat that isn’t digested is not absorbed by your body and the body passes it out with your poo. This helps you avoid gaining weight. However, this does not guarantee losing weight. Therefore, exercising and following a healthy and balanced diet is important during orlistat treatment.

How to take orlistat

The typical orlistat dose is to take one 120mg capsule with each of your three main meals a day. It can be taken before, during, or up to an hour after each meal. 

It only works when a meal contains fat. This means if you miss a meal there is no need to take a dose of orlistat. If you eat a meal containing no fat, there is also no need to take a dose. If you have fat with all three meals, you would take orlistat three times a day.

Side effects

The most common side effects of orlistat are to do with your digestive system. This includes abdominal pains, liquid stools, and an increased need to go to the toilet. By causing your body to get rid of undigested fat with your poo, it can cause fatty or oily stools. If your diet is high in fat, or you have a particularly high-fat meal with orlistat, the likelihood of these side effects increases.

For women who take an oral contraceptive, additional contraceptive methods (e.g condoms) are advised if they suffer from severe diarrhoea during treatment with orlistat.

Further information can be found in the patient information leaflet.

Orlistat and diet

Your diet is very important when taking orlistat. The best way to maximise the effectiveness of orlistat is to make sure your diet is optimised for orlistat treatment.

When taking orlistat, it is crucial that your diet is hypocaloric. This means that your calorie intake is less than the calories you burn. This is also called a calorie deficit. A good guideline is to try to consume around 500-600 calories less than you normally would every day.

The NHS has a handy calorie checker which helps you look up the calorie content of over 150,000 different foods and drinks.

As well as being hypocaloric, your orlistat diet should:

  • Be well-balanced and rich in fruits and vegetables
  • Have your daily intake of carbohydrate, protein and fat evenly shared over 3 main meals
  • Contain approximately 30% of calories from fat

This means that if your daily intake is 1800 calories, you should have 600 calories from fat every day. The NHS website has information on how to read food labels to help you check how much fat a meal contains.

Order Xenical (branded orlistat) online from 52p per capsule

Tips to reduce fat intake

Some people might find they have a high-fat diet containing more than 30% fat. Here are some tips to reduce fat consumption to get it in line with an orlistat diet:

  • Swap whole milk for semi-skimmed or skimmed milk
  • Swap full-fat yoghurts to fat-free or low-fat yoghurts
  • Use reduced-fat spreads instead of butter
  • Rather than frying or roasting food, try to grill, steam or poach instead
  • Buy leaner cuts of meat that contain less fat like reduced-fat mince or turkey breasts
  • Try to swap unhealthy snacks like chocolate for healthier snacks like bananas or apples



You can increase how many calories you burn by increasing how much you exercise. Regularly exercising can help keep you in a hypocaloric diet when taking orlistat.

When taking orlistat, NHS physical activity guidelines are a useful guide to follow. They suggest doing some type of physical activity every day. This translates to at least 150 minutes of moderate physical exercise a week or 75 minutes of intense physical exercise a week.

The NHS has a 12-week fitness plan for beginners that can be used to burn calories and keep you in a calorie deficit. This 12-week plan can fit in well with treatment because orlistat is recommended to initially be taken over a 12 week period.

During this 12 week treatment period, you should aim to lose about 5% of your body weight. Your doctor may discontinue orlistat after 12 weeks if you are unable to lose at least 5% of your body weight in this time.


To get the best results from orlistat you need to make sure you optimise your diet and exercise regularly while taking it.

Optimising your diet with orlistat means:

  • Having a hypocaloric diet (consuming less than you burn)
  • Consuming a well-balanced diet rich in fruits and vegetables
  • Sticking to 3 main meals a day and sharing your daily intake of fat between all 3 meals
  • Consuming around 30% of your calories from dietary fat

You can increase the number of calories you burn by increasing your physical activity. Try to stick to the NHS physical activity guidelines and try to be physically active every day. The NHS has a 12-week fitness plan for beginners, which may work well for people starting orlistat because it is usually recommended to be taken for a 12 week period.

Orlistat has been proven to be effective in clinical trials. By optimising your diet and exercising regularly while taking it, you give it the best chance to work well for you and help you to lose weight.

You can order orlistat 120 mg capsules online from Simple Online Pharmacy. It requires a prescription so you’ll need to complete an online doctor questionnaire. Our UK GPs can then assess this questionnaire to make sure it is safe and appropriate to prescribe for you.

Once approved, our doctors will prescribe orlistat and send a prescription to our UK registered pharmacy team. Our pharmacy team will dispense it for you and dispatch it via royal mail to your delivery address.

At Simple Online Pharmacy, we also offer the branded version of orlistat, Xenical, and injection weight-loss pens called Saxenda and Wegovy.

See our full range of prescription weight loss treatments

Content Reviewed: 22/10/2020