Orlistat is a weight loss medication available in the UK in two strengths — 60mg (available over the counter as Alli) and 120mg (prescription strength, also known by the brand name Xenical). It is licensed for weight management in adults with obesity (BMI ≥30) or overweight (BMI ≥27) with at least one weight-related health condition. At HEBA Online Pharmacy, we supply prescription-strength Orlistat 120mg following a clinical assessment.

Orlistat works differently to injectable weight loss treatments. Rather than acting on appetite hormones, it works directly in the gut by blocking the action of lipase enzymes that break down dietary fat. This prevents approximately one third of the fat you consume from being absorbed into the body. The undigested fat is instead passed out of the body in your stools.

In clinical trials, patients taking Orlistat 120mg alongside a reduced-calorie diet lost an average of 8–10% of their body weight over 12 months. In the landmark XENDOS trial — the largest long-term study of Orlistat involving over 3,300 patients followed over 4 years — patients lost an average of 5.8kg compared to 3.0kg in the placebo group. Around 50–60% of patients lose more than 5% of their body weight at 12 months, and approximately 25% achieve more than 10% weight loss.

Take one 120mg capsule three times daily with each main meal that contains fat, or up to one hour after each meal. If you skip a meal or eat a meal with no fat content, you can omit that dose. Orlistat should always be taken alongside a nutritionally balanced, reduced-calorie diet where no more than 30% of calories come from fat.

Yes. Orlistat 120mg is a Prescription Only Medicine (POM) in the UK. At HEBA Online Pharmacy, you will need to complete a short online clinical assessment before a prescription can be issued by one of our qualified prescribers. A lower-strength version (Orlistat 60mg, sold as Alli) is available over the counter, but the prescription-strength 120mg capsule is significantly more effective.

Orlistat 120mg is suitable for adults with a BMI of 30 or above, or a BMI of 27 or above alongside a weight-related health condition such as type 2 diabetes, hypertension, or high cholesterol. It is suitable for patients who prefer an oral treatment or who are not eligible for injectable weight loss medications.

Orlistat produces more modest weight loss than the newer injectable GLP-1 treatments. On average, Orlistat achieves around 8–10% body weight loss at 12 months, compared to approximately 8–9% with Saxenda, 15% with Wegovy, and up to 22.5% with Mounjaro. However, Orlistat remains a valuable option for patients who prefer an oral tablet, cannot tolerate injections, or have contraindications to GLP-1 treatments.

The most common side effects of Orlistat are gastrointestinal and are directly related to its mechanism of action. They include oily or fatty stools, oily spotting on underwear, frequent or urgent bowel movements, flatulence with discharge, and oily discharge. These side effects are more likely to occur if you eat high-fat meals and typically reduce as you adjust to a lower-fat diet.

The most effective way to minimise gastrointestinal side effects is to strictly follow a low-fat diet while taking Orlistat. Aim for no more than 15g of fat per meal. Spreading your fat intake evenly across three meals per day also helps. Keeping a food diary to track fat intake can be a useful tool during treatment.

Yes. Because Orlistat blocks fat absorption, it can also reduce the absorption of fat-soluble vitamins A, D, E, and K. It is therefore recommended to take a daily multivitamin supplement containing these vitamins while on Orlistat treatment. Take your multivitamin at least 2 hours before or after your Orlistat dose, or at bedtime.

Orlistat can interact with certain medications. It may reduce the absorption of ciclosporin, antiretroviral HIV medications, levothyroxine, and amiodarone. It can also affect the absorption of warfarin, requiring closer INR monitoring. Always inform your prescriber and pharmacist of all medications you are taking before starting Orlistat.

Yes, Orlistat can be used in patients with type 2 diabetes and may help improve blood sugar control alongside weight loss. However, as weight loss progresses, your diabetes medications may need to be reviewed and adjusted by your GP or diabetes team, particularly if you are taking insulin or sulphonylureas, to reduce the risk of hypoglycaemia.

Alcohol itself does not directly interact with Orlistat. However, alcoholic drinks often contain significant calories and can undermine your weight loss progress. Excessive alcohol intake is not recommended during any weight management programme. Moderate, mindful alcohol consumption is advisable.

Yes, Orlistat can be used long term. Treatment is typically reviewed at 12 weeks — if you have not lost at least 5% of your body weight by this point, your prescriber will reassess whether continuing treatment is appropriate. Some patients continue Orlistat for up to 2 years or longer under medical supervision.

No. Orlistat is not recommended during pregnancy or breastfeeding. If you become pregnant while taking Orlistat, stop treatment immediately and consult your doctor. Weight loss is generally not recommended during pregnancy.

If you miss a dose, skip it and take your next dose with your next fat-containing meal. Do not take a double dose to make up for a missed one. If you regularly miss doses, this will reduce the effectiveness of your treatment.