Orlistat 120mg Capsules for Weight Loss

What is orlistat?

Orlistat capsules are used to help people lose weight by reducing the amount of fat your body absorbs from food, lowering your calorie intake when used alongside a healthy diet and regular physical activity.

Because it works in the gut rather than the brain, orlistat does not suppress appetite. This it means it’s different to weight loss injections like Mounjaro and Wegovy.

In the UK, it’s available in 120 milligrams (mg) capsules under the brand name Xenical and as generic orlistat.

What is orlistat used for?

Orlistat is used to support weight loss and weight management in adults with obesity or overweight with weight-related health risks.

It’s usually prescribed alongside positive lifestyle changes, like balanced nutrition and increased physical activity, to help support sustainable, long-term weight loss.

How do orlistat pills work for weight loss?

Orlistat belongs to a group of medicines called lipase inhibitors.

Lipase is an enzyme that helps break down fat in food. Orlistat works by blocking this enzyme in the digestive system. As a result, around one-third of dietary fat is not absorbed and instead passes through the body as stool. This reduces overall calorie intake and may help support gradual weight loss.

For best results, orlistat should be used alongside:

• a balanced diet
• regular physical activity
• reduced calorie intake

Meals high in fat may increase the likelihood of digestive side effects.

How effective is orlistat for weight loss?

Orlistat pills can support modest but meaningful weight loss when combined with lifestyle changes.

Clinical studies show that people taking Orlistat alongside diet and exercise often lose around 5–10% of their starting body weight over time.

Even this level of weight loss may help improve your health, including:

• Blood pressure: Indicates a lower risk of stroke, heart attack, kidney disease, and damage to blood vessels compared to high blood pressure.
• Cholesterol levels: Lowering cholesterol is crucial to reducing the risk of cardiovascular diseases, like heart attacks, strokes, and peripheral arterial disease.
• Blood sugar control: Lower, stable blood sugar levels reduce the risk of heart disease, stroke, kidney disease, and vision problems.

How does generic orlistat compare to Xenical?

Generic orlistat and branded Xenical work in the exactly the same way:

Both contain the same active ingredient and work in the same way by blocking fat absorption to support weight management. The primary differences are that generic orlistat pills are significantly cheaper, while Xenical is the original, branded, and often more expensive version.

Who can use orlistat?

Orlistat weight loss pills may be suitable for adults with obesity or overweight who have struggled to lose weight through lifestyle changes alone.

Healthcare professionals may consider orlistat for people with:

• BMI 30 or higher
• BMI 28 or higher with weight-related conditions
• increased risk of metabolic conditions

A clinician will review medical history before prescribing.

Orlistat dosages

The standard prescription dose of orlistat is a 120mg capsule, taken three times daily with meals.

The capsule should be taken during or within one hour after eating a meal containing fat. If a meal does not contain fat, the dose may be skipped.

Is orlistat safe?

Orlistat is generally considered safe when used as prescribed and alongside appropriate lifestyle changes.

However, it may not be suitable for everyone, and you should always speak to your clinician about all your available treatment options to find out which might best support your weight-management journey.

Orlistat should not be used by people who:

• are pregnant
• are breastfeeding
• have chronic malabsorption syndrome
• have cholestasis (bile flow problems)

Always speak to a clinician before starting treatment.

When to seek medical advice

You should seek medical advice from a licensed clinician if you experience any of the following side effects upon starting orlistat pills, or any other weight-loss treatment:

• severe abdominal pain or digestive issues
• signs of an allergic reaction, like a rash
• persistent vomiting or diarrhoea
• yellowing of the skin or eyes

How do I take orlistat 120mg capsules?

Orlistat capsules should be taken with meals containing fat, up to three times per day.

1. 1. Take ONE capsule with breakfast, lunch, and dinner.
2. 2. Swallow with water.
3. 3. Skip the dose if the meal contains no fat (for example, a bowl of fruit or vegetable broth).
4. 4. Follow a balanced, reduced-calorie diet alongside taking the treatment.

Eating very high-fat meals may increase side effects.

Where can I buy orlistat in the UK?

Orlistat is a prescription-only medicine in the UK. This means it must be prescribed by a doctor or prescribing pharmacist after a medical assessment.

You can buy orlistat tablets online through Chemist4U. Simply answer a few questions, and one of our clinicians will assess whether the treatment is the right fit for your needs.

Orlistat prices

The price of orlistat tablets can vary depending on the pharmacy and treatment duration.

Costs usually depend on:

• prescription consultation
• number of capsules supplied
• treatment length

Prices at Chemist4U start from £33.59 for a pack of 84 capsules.

NHS prescription availability

Orlistat weight loss pills may be prescribed on the NHS if certain criteria are met. 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 orlistat 120mg typically take to work?

Orlistat begins working as soon as it’s taken with meals containing fat. However, visible weight loss usually takes several weeks. The key is perseverance and patience. Everyone is different, and you should never compare your weight loss journey to others.

Healthcare professionals often review progress after three months to determine whether your treatment should continue.

How long does orlistat stay in your system?

Orlistat mainly works within the digestive system and is not significantly absorbed into the bloodstream.

Most of the medicine leaves the body within 24–48 hours after the last dose.

How much weight can I lose in a week?

Weight loss with orlistat 120mg varies between individuals.

A gradual rate of 0.5–1 kilogram per week is generally considered a healthy and sustainable pace when combined with lifestyle changes.

Rapid weight loss is not typically recommended as it’s not generally healthy or sustainable.

Potential orlistat side effects

Most side effects of orlistat are related to digestion and occur because fat is not fully absorbed.

Common side effects include:

• oily or fatty stools
• frequent bowel movements
• abdominal discomfort and severe bloating
• flatulence (wind)

These effects are often more noticeable when meals are high in fat and in the early stages of your treatment journey.

How long do the side effects last?

Orlistat side effects are usually most noticeable during the first few weeks of treatment and may improve as eating habits adjust.

Following a naturally lower-fat diet can help reduce symptoms.

How does orlistat interact with other medications?

Orlistat may interact with certain medicines and nutrients:

• oral conceptives (severe diarrhoea may reduce effectiveness)
• fat-soluble vitamins (A, D, E, and K) may be absorbed less effectively
• vitamin supplements should be taken at least two hours apart
• levothyroxine (used for thyroid conditions)
• warfarin and anticoagulants (blood clotting medicines)
• ciclosporin (immune suppressant)
• HIV medications
• epilepsy medications

Orlistat 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 orlistat.

Are there alternatives to orlistat pills?

Other weight management treatments may be considered depending on individual health needs.

Examples include:

• lifestyle-based weight management programmes
• GLP-1 medicines like Wegovy
• dual-hormone treatments like Mounjaro

A clinician can help determine which approach may be appropriate.

Orlistat storage information

Orlistat capsules should be stored:

• below 25°C
• in their original packaging
• away from moisture
• out of reach of children

Always check expiry dates before use and never take orlistat tablets if the package is expired, damaged or spoiled.

Frequently asked questions about orlistat

Is there an orlistat diet plan?

Yes. A balanced, lower-fat, calorie-controlled diet is recommended when taking orlistat because the medicine blocks fat absorption. Meals high in fat may increase digestive side effects.

Can I take orlistat once a day?

Orlistat is usually taken up to three times daily with meals containing fat. Taking it once daily is unlikely to provide the intended effect.

Can you take orlistat with Mounjaro?

While Mounjaro and orlistat work differently, because there is limited safety data on using them together, they should only be combined under close medical supervision.

Can I drink alcohol while taking orlistat?

Alcohol does not directly interact with orlistat, but it contains calories and may slow weight loss progress.

Foods to avoid when taking orlistat

Meals high in fat may increase digestive side effects. It can help to reduce foods like fried meals, fatty meats, and high-fat snacks.

Sources

• Orlistat for obesity. NICE. [Accessed 10 March 2026].
• Fat - Nutritional Information. BFN. [Accessed 10 March 2026].
• Obesity: identification, assessment and management (CG189). NICE. [Accessed 10 March 2026].
• Orlistat summary of product characteristics. EMC. [Accessed 10 March 2026].
• Obesity overview. NHS. [Accessed 10 March 2026].
• Healthy weight guidance. NHS. [Accessed 10 March 2026].