- For weight loss
- Cheaper generic orlistat available
- Just one tablet three times a day
- Always read the patient information leaflet before use.
84 Tablets
168 Tablets
252 Tablets
How does Xenical work for weight loss?
How to take Xenical for the best weight loss results
Can I buy Xenical online in the UK?
How long does Xenical 120mg take to work?
How long does Xenical stay in your system?
How much weight can I lose in a week?
Potential Xenical side effects
What is Xenical?
Xenical is a prescription-only weight loss medication containing 120mg of the active ingredient orlistat. It works by reducing the amount of fat your body absorbs from food, helping support weight management. Xenical should be taken alongside a reduced-calorie diet and regular exercise for healthy, sustainable results and to reduce any potential side effects.
The orlistat in Xenical blocks enzymes in the digestive system that break down fat.
When fat cannot be absorbed, it passes through the body in stools rather than being stored. This can help support gradual weight loss when combined with a balanced diet and physical activity.
What is Xenical used for?
Xenical is used to support weight loss and weight management in adults with obesity or overweight individuals who have weight-related health risks like high blood pressure or type 2 diabetes.
According to the NHS, medicines like Xenical are sometimes recommended for people who have obesity or weight-related health conditions when lifestyle changes alone have not been enough to reduce weight.
How does Xenical work for weight loss?
Xenical works by blocking digestive enzymes called lipases, which normally break down fat from food so it can be absorbed by the body. By preventing this process, about one-third of dietary fat passes through the body undigested.
This means fewer calories from fat are absorbed, helping create a calorie deficit when used alongside healthy eating and exercise.
Because Xenical specifically targets fat absorption, it's most effective when combined with a low-fat diet. Eating high-fat meals while taking Xenical may increase digestive side effects.
How effective is Xenical for weight loss?
Clinical studies show Xenical can help people lose more weight than a diet alone when taken alongside lifestyle changes. Many patients lose around 5–10% of their starting body weight over several months.
According to guidance from NICE, weight loss of 5–10% of body weight can significantly improve your health, including lower blood pressure, regulated blood sugar levels and lower cholesterol levels.
Even modest weight loss can reduce the risk of long-term conditions like cardiovascular disease and type 2 diabetes.
Is Xenical better than orlistat?
Xenical contains the same active ingredient as generic orlistat (120mg). The main difference is that Xenical is the original branded version, while orlistat may be available as a generic alternative, usually at a lower cost. Both work in the same way.
Always speak to your clinician to explore which treatment is right for you.
Who can use Xenical?
Xenical is intended for adults with obesity or overweight individuals who have weight-related health risks. It should only be used after assessment by a healthcare professional.
Xenical may be suitable if:
- your BMI is 30 or above
- your BMI is 28 or above with weight-related conditions
- lifestyle changes alone have not been effective
Xenical is not suitable for everyone. You should not take it if you:
- are pregnant or breastfeeding
- have chronic malabsorption syndrome
- have cholestasis (a liver condition affecting bile flow)
Your doctor or pharmacist will assess whether Xenical is appropriate for you based on several contributing factors.
Standard Xenical dosages
The standard Xenical dosage is 120mg capsules taken three times daily with meals containing fat.
Typical dosing guidance:
- One 120mg capsule with breakfast, lunch and dinner.
- Take during the meal or within one hour after eating .
- Skip the dose if your meal contains no fat .
Xenical should always be taken alongside a reduced-calorie, nutritionally balanced diet.
Is Xenical safe?
Xenical is considered safe when prescribed appropriately and used according to medical guidance. It has been approved for use in weight management by European and UK regulators.
Medicines like Xenical are regulated by the Medicines and Healthcare products Regulatory Agency (MHRA), which monitors the safety and quality of medicines used in the UK.
However, like all medicines, Xenical may cause side effects and may not be suitable for everyone. A medical consultation is required before starting treatment.
How to take Xenical for the best weight loss results
To achieve the best results with Xenical, it should be combined with long-term lifestyle changes. This can include:
- following a balanced reduced-calorie diet
- trying to limit your dietary fat intake
- eating regular meals
- exercising regularly
- monitoring your weight and tracking your progress
The NHS recommends at least 150 minutes of moderate physical activity per week for adults as part of maintaining a healthy weight.
Can I buy Xenical online in the UK?
Xenical is a prescription-only medication in the UK. This means you must be assessed by a healthcare professional before purchasing it.
You may be able to buy Xenical online with Chemist4U following an online consultation and prescription approval by one of our clinicians.
Always ensure you buy medicines from a pharmacy registered with the General Pharmaceutical Council (GPC) to ensure authenticity and patient safety.
Xenical prices
The price of Xenical varies depending on the pharmacy, quantity purchased and whether it's obtained privately or through the NHS.
Branded medications like Xenical may cost more than generic orlistat, although both contain the same active ingredient.
At Chemist4U, the price of Xenical starts at £45.99 for 84 tablets.
NHS prescription availability
Some patients may receive Xenical on an NHS prescription if they meet clinical eligibility criteria for weight-management medication. You’ll need to have shown significant effort to lose weight through lifestyle changes, and have a:
- BMI of 30 or above (obesity)
- BMI of 28 or above with weight-related health conditions
How long does Xenical 120mg take to work?
Xenical begins working immediately by preventing fat absorption from meals. However, noticeable weight loss typically occurs gradually over several weeks when combined with dietary changes and exercise.
Healthcare providers usually assess progress after 12 weeks of treatment. If you’ve not lost at least 5% of your body weight, they may recommend you stop taking Xenical.
Always speak to your clinician if you have any questions or concerns regarding the effectiveness of your prescribed treatment.
How long does Xenical stay in your system?
Xenical works locally in the digestive system and is minimally absorbed into the bloodstream. Most of the medication leaves the body within a few days after stopping treatment.
Because Xenical primarily acts within the gut, its effects depend on whether dietary fat is present in meals.
How much weight can I lose in a week?
Weight loss with Xenical varies depending on individual factors such as diet, activity level and starting weight. Many people lose around 0.5–1kg per week during early treatment when following a reduced-calorie diet.
Sustainable weight loss is generally considered to be 0.5–1kg per week, according to NHS weight management guidance.
Gradual weight loss is associated with better long-term maintenance and reduced health risks.
Potential Xenical side effects
The most common Xenical side effects affect the digestive system because the medication blocks fat absorption.
Common side effects include:
- oily stools
- increased bowel movements
- flatulence
- urgent need to use the toilet
- abdominal discomfort
These effects are usually mild and often improve as your body adjusts to treatment and fat intake is reduced.
Seek urgent medical help if you experience:
- severe abdominal pain
- signs of liver problems (yellowing of skin or eyes)
- allergic reactions such as swelling, rash or breathing difficulties
If you experience severe or persistent symptoms, contact your doctor or pharmacist immediately.
How long do the side effects last?
Most digestive side effects improve within the first few weeks of treatment, especially if dietary fat intake is reduced. Following a balanced, lower-fat diet can help minimise symptoms.
How does Xenical interact with other medications ?
Xenical may interact with some medications, affecting how they work.
Important interactions include:
- oral contraceptives (severe diarrhoea may reduce effectiveness)
- levothyroxine (used for thyroid conditions)
- warfarin and anticoagulants (blood clotting medicines)
- ciclosporin (immune suppressant)
- HIV medications
- epilepsy medications
- fat-soluble vitamins (A, D, E, and K) may be absorbed less effectively
- vitamin supplements should be taken at least two hours apart
Xenical is not recommended during pregnancy or breastfeeding because weight-loss medications are not considered appropriate during these periods.
Always inform your healthcare provider about any medicines or supplements you are taking before starting Xenical.
Xenical alternatives
Other weight-management treatments may be available depending on your health needs and eligibility.
Possible alternatives include:
- generic orlistat capsules
- prescription GLP-1 injections like Mounjaro or Wegovy
- lifestyle weight management programmes
Your doctor or pharmacist can help determine the most suitable option based on your BMI, medical history and health goals.
Storage information
Store Xenical capsules at room temperature below 25°C and keep them in their original packaging to protect from moisture.
Keep out of reach of children and do not use after the expiry date printed on the packaging.
Always follow storage instructions included in the patient information leaflet.
Sources
- Obesity. (2023). NHS. [Accessed 10 March 2026].
- Orlistat. (2023). NHS. [Accessed 10 March 2026].
- Obesity: identification, assessment and management (CG189). (2014). NICE. [Accessed 10 March 2026].
Find similar products
Xenical (Orlistat) Capsules Reviews
Advice & Guides
Do weight loss pills really work?
When it comes to losing weight, people want to do it quickly. Lots of exercise, strict diet, and supplements, including weight loss pills, are usually taken in the hope that this will speed up the process.
Funding your weight loss treatment
Can I take Xenical if I’m not overweight?
If your weight is within a healthy BMI range or lower then you should not take Xenical.
This treatment is specifically designed to help those who are obese lose weight more quickly and form good diet and exercise habits as they return to a healthy weight.
We would not recommend them to anyone who does not need to lose weight for the benefit of their health or to those who are a healthy weight and want to lose weight purely for cosmetic purposes.
Can I take two Alli instead of one Xenical?
No. Alli contains a lower dose of orlistat (60mg). Taking two capsules without medical guidance is not recommended. Always follow the dosing instructions provided by a healthcare professional.
Can you take Ozempic and Xenical together?
Can you take Xenical if you have no gallbladder?
Does Xenical work on existing fat?
Does Xenical suppress appetite?
Do I need to have a certain BMI to take Xenical capsules?
Xenical capsules should usually only be taken by those who have a BMI (Body Mass Index) of 30 or above.
This number can be lowered to 28 if you have a weight-related condition that could be eased by weight loss, for example, type 2 diabetes or high blood pressure.
Even then, your BMI is not the only factor to consider, your doctor will need to be sure that this treatment is right for you and that you are dedicated to making the lifestyle changes necessary for orlistat to work.
If you’re unsure what your BMI is, you can use this handy calculator to work it out using your height and weight.
Is Xenical the same as Alli and Orlos?
Xenical, Alli, and Orlos are all weight loss medications that share the same active ingredient, orlistat.
This means that they all work in the same way, but are created by different manufacturers.
The biggest difference that you should note is the strength of the active ingredient in each product.
Alli and Orlos both contain 60mg of orlistat in each capsule, whereas Xenical contains 120mg in each capsule and gives you a higher daily dose of orlistat than the other brands.
Naturally, this increase in dose comes with extra precautions, which is why Xenical is only available as a prescription medication whereas Alli and Orlos can be bought over the counter from your pharmacy.
Should I take orlistat at a certain time?
You should take each capsule immediately before or during a meal.
If you forget to take your medication, you can take it up to one hour after you finish eating.
This medication only works if there is fat in your food, so if your food contains no fat or if you skip a meal you should not take a capsule.
However, we would recommend splitting your daily fat intake evenly throughout your three daily meals.
What should I eat when taking Xenical? 
A balanced, reduced-calorie diet with moderate fat intake is recommended. Spread fat intake evenly across meals and prioritise vegetables, lean proteins and whole grains.
Will Xenical make me constipated?
Constipation is not a listed side effect of Xenical, even though digestive problems are common while taking this medication.
This doesn’t mean that Xenical definitely will not cause constipation, as everyone reacts to medications slightly differently, but it is unlikely to happen to you.
If you do experience constipation after taking this medication, we’d recommend speaking to your doctor or pharmacist and asking for their advice.
They’ll be able to assess whether this weight loss medication is the best thing for you and help you to make a decision about your ongoing treatment.
Will this medication affect my birth control?
Orlistat usually won’t affect contraception, but some of the potential side effects can affect oral birth control like the mini pill or combined pill.
If you do take oral contraception you should consider using a second method of contraception, like condoms, when you first start your treatment.
One of the potential side effects of orlistat is diarrhoea, and if you have severe diarrhoea it can mean that your contraceptive pill won’t be absorbed properly in your system.
If this happens, you won’t be effectively protected from pregnancy, which is why you would need to use a second method of contraception.
If you have severe diarrhoea after taking this medication you should speak to your doctor or pharmacist as soon as you can, as this treatment may not be right for you.
How long does orlistat take to work?
Orlistat will get to work reducing the amount of fat absorbed from your food right away.
However, this doesn’t mean you’ll see weight loss results immediately.
Weight loss is always a slow process and as much as this treatment can help, how quickly you shed the pounds will ultimately be decided by what you eat and how much exercise you do.
