Xenical is a drug that has been developed to help with weight loss. The active ingredient in Xenical is Orlistat which is a drug designed to block the enzyme that is needed to break down fats in order for them to be absorbed by our bodies. More information

A doctor will review your order and write you a prescription, if appropriate. This prescription is then forwarded to a pharmacy. The pharmacy will have your medicine delivered to you within one to three working days. Read more about this process here.

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Being overweight is a common problem in modern society. 1 in 4 adults in the UK is obese and 1 in 13 deaths in Europe is caused by obesity. Our lifestyle means that we eat too much, easily available, high-calorie food and we don’t get enough exercise. This leads to weight gain and eventually a diagnosis of obesity. Being overweight is linked to many medical problems and diseases such as stroke, heart disease osteoarthritis and some cancers. It can also cause other problems with your joints. Obesity leads to isolation and depression if you can’t get around easily and don’t get out and about to talk to other people. Losing weight is not an easy thing to do and although a healthy diet and an exercise plan are the best way to lose weight it’s frustrating when these don’t work. When you have a lot of weight to lose, it can feel like a never-ending task, results take time and it can be hard to do it on your own. If you do want to lose weight, there are a variety of medication options out there to help you alongside a diet and exercise programme. Different types of weight loss medication act on the body in different ways. Xenical, for example, helps to prevent your body from absorbing some of the fat in the food you eat. Other products may suppress your appetite. You will need to consider a variety of things to find the right medication for you and your doctor will be able to help you do this. 

Below you can find out more about Xenical so you can consider whether it might be a good option to help you in your weight loss journey. 

What is Xenical? 

Xenical is a drug that has been developed to help with weight loss. The active ingredient in Xenical is Orlistat which is a drug designed to block the enzyme that is needed to break down fats in order for them to be absorbed by our bodies. Each Xenical capsule contains 120mg of Orlistat. The other ingredients contained in the capsule are microcrystalline cellulose, sodium starch glycolate, povidone, sodium laurilsulfate and talc. 

Studies have shown that using Xenical alongside a diet and exercise programme given to you by your doctor or a qualified nutritionist leads to increased weight loss compared to a similar programme without using Xenical. 

When is Xenical used? 

Xenical works on your digestive system. It is known as an intestinal lipase inhibitor. This means that the drug is designed to block around one-third of the fat in the food you eat from being digested. You take it when you eat your meals and it attaches to the enzymes in your digestive system to stop them from breaking down some of the fat you have eaten during your meal. As the fat remains undigested it cannot be absorbed by your body. The fat is then eliminated when you use the toilet. Dietary fat is high in calories, if you take Xenical it will help you to absorb fewer of these calories from fat. You will still absorb all the calories from protein, carbohydrates and alcohol which is why you need to follow a specific diet. You will need to establish a healthy, low-fat diet and exercise programme alongside taking Xenical to get the full effects. Your doctor or nutritionist will provide this. When you start taking Xenical it is for a 12-week period. In order to continue taking Xenical on a longer-term basis, you must achieve at least 5% weight loss within the first three months. It is worth making a note if you don’t follow your diet or exercise programme for any reason so that you can share these with your doctor. 

How do you use Xenical? 

You should always follow the instructions given to you by your doctor or pharmacist for taking Xenical.On the whole, Xenical should be taken with water. You take Xenical 3 times a day, with each of your 3 main daily meals. You can take it immediately before, during or up to one hour after a meal. Xenical should be taken with a well-balanced, calorie-controlled diet that is rich in fruit and vegetables. You should also ensure that around 30% of your calorie intake is coming from fat. Your meal plan should include sufficient protein, carbohydrate and fat at each meal as the drug has an immediate effect on what you consume when you take it, rather than a long-term effect. As Xenical works on your fat intake you should avoid eating snacks that contain fat outside of your main meals, where you are taking the medication to reduce your fat absorption. If you eat a meal that contains no fat or you skip a meal then you can skip taking Xenical as it will have no effect if there is no fat to block from breaking down. 

What dosages are there? 

Xenical usually comes in 120mg capsules. The capsules are turquoise and come in glass bottles or packs containing 21, 42 or 84 capsules. The maximum dose is three capsules per day. Each capsule should be taken immediately before, during or up to one hour after each main meal of the day. You should be having 3 main meals a day.  

If you miss a meal or eat a meal containing no fat, do not take your Xenical capsule as it only works by preventing the digestion of fat consumed and it only works with immediate effect. If you are not consuming fat there is no point in taking the capsule.If you forget to take Xenical, take it as soon as you remember, provided this is within one hour of your meal. Then continue with your usual pattern. Do not take a double dose. If you miss several doses please speak to your doctor. Especially if this is during the first 12 weeks of using Xenical as it may affect your long-term results and your doctor’s ability to prescribe Xenical on a long-term basis.This is because you will need to achieve a 5% weight loss within the first three months in order to continue taking Xenical. Xenical has been tested on a long-term basis of up to four years though often patients only take it for 12 months. 

What are the side effects? 

As with all medication Xenical can cause side effects, although not everyone who takes Xenical will experience them. 

Most of the common side effects associated with taking Xenical are caused by the process of eliminating the fat from the body via your faeces. Many of these side effects occur during the early stages of the treatment and settle down over time to a manageable or rare occurrence depending on the food you eat. The side effects are particularly strong after eating fatty foods and can be lessened by eating a lower fat diet. Do not avoid fat completely as Xenical only works by preventing fat absorption so if there is no fat to absorb you would not gain any benefit from taking it. 

Common side effects that are experienced by more than 1 in 10 people taking Xenical are: 

  • Headache 
  • Abdominal pain/discomfort 
  • Urgent or increased need to use the toilet 
  • Wind 
  • Offensive smelling fatty stools 
  • Oily discharge 
  • Liquid stools 
  • Low blood sugar levels (experienced by some people with type 2 diabetes) 

Again, these can be limited over time by following a healthy diet plan Less common side effects experienced by around 1 in 100 people taking Xenical include: 

  • Rectal pain or discomfort 
  • Soft stools.
  • Liver disorder, yellowish stool, and eye. Contact your doctor. 
  • Incontinence (stools) 
  • Bloating (experienced by some people with type 2 diabetes) 
  • Tooth/gum disorder 
  • Irregular periods 
  • Tiredness 

In a few cases the following side effects have been reported: 

  • Allergic reactions (itching, rashes, weals) 
  • Breathing difficulties 
  • Nausea and vomiting 
  • Skin blisters 
  • Diverticulitis 

If you are having trouble with side effects when taking Xenical please talk to your doctor who may be able to help. 

When shouldn’t you use Xenical? 

You should not take Xenical in the following conditions: 

  • If you are pregnant or breastfeeding
  • If you are a child
  • If you have cholestasis (a liver disorder) 
  • If you are allergic to orlistat or any of the other ingredients

If you suspect you may be suffering a severe allergic reaction contact emergency services immediately. Xenical does NOT affect your ability to drink alcohol or drive and operate heavy machinery. 

Does Xenical interact with other medications? 

Xenical can be taken alongside most other drugs and does not interact with alcohol. However, you should always discuss any medication you are taking (even herbal supplements) with your doctor when you are being prescribed any new medication. 

It is recommended you do not take Xenical alongside: 

  • Cyclosporin 
  • Acarbose 

You may need close monitoring if you are taking Xenical alongside: 

  • Warfarin or another anticoagulant 
  • Amiodarone 
  • Antiepileptic drugs 
  • Medicines to treat HIV 
  • Iodine salts and/or levothyroxine (cases of hypothyroidism may occur or worsen)  

As you continue your treatment with Xenical you may need to adjust the doses of any other medication you are taking as you lose weight, for example, high cholesterol or diabetes. There are two reasons for this. 

  1. You may find that as you lose weight these conditions start to improve 
  2. Your weight will have been taken into account when deciding on the dose for these drugs so if you lose weight it will naturally have to be altered. 

Xenical should be taken with caution alongside antidepressant or antipsychotic drugs as it may alter the effectiveness of these drugs. There is also a chance that Xenical may reduce the effectiveness of oral contraceptives. This is because of the side effect of loose stools or diarrhea. You should plan to use a different or additional contraceptive while taking Xenical to avoid unexpected pregnancies. Xenical can reduce the absorption of some fat-soluble nutrients, in particular beta-carotene and vitamin E. You should follow your doctor’s advice when it comes to your diet whilst taking Xenical so that you don’t miss out on nutrition that’s essential to your long term health. 

Where can I buy Xenical? 

You can buy Xenical from any pharmacy, a local pharmacy, supermarket pharmacy or online pharmacy. You will need a prescription to purchase it. 

Can I get Xenical without a prescription? 

You cannot by Xenical as an over the counter medicine, you will need a prescription from a doctor to purchase Xenical from the pharmacy of your choice. 




Cheplapharm Arzneimittel GmbH Package Leaflet Xenical 120mg (May 2017) Retrieved from https://www.medicines.org.uk/emc/files/pil.2592.pdf 

Sheffield Teaching Hospitals NHS Foundation Trust Dietary Advice for Patients Taking Orlistat (Xenical) (November 2016) Retrieved from https://publicdocuments.sth.nhs.uk/pil1885.pdf 

Assessed by:

Dr Wouter Mol, General practitioner
Registration number: BIG: 9057675501

Dr Wouter Mol studied medicine at the University of Groningen. From 2002 to 2003, he served as a resident in neurology, and from 2003 to 2005 he served his residency training in internal medicine and emergency medicine. Wouter Mol has been working as a GP since 2005.