How To Use Orlistat
Complete Step-by-Step Usage Guide, Dosage Instructions & Safety Information
Key Takeaways: How to Use Orlistat Correctly
- Dosage: One 120mg capsule with each main meal that contains fat (up to three times daily).
- Timing: Take immediately before, during, or up to one hour after the meal.
- Low‑fat diet: Follow a reduced‑calorie diet with about 30% of calories from fat to reduce side effects.
- Missed dose: If you forget, take it as soon as you remember within 1 hour of the meal; otherwise skip.
- Vitamins: Take a daily multivitamin (A, D, E, K) at bedtime, at least 2 hours after orlistat.
- 12‑week review: Treatment should be reassessed if you haven’t lost at least 5% of your body weight after 12 weeks.
Orlistat is a prescription medication that helps you lose weight by blocking fat absorption. Using it correctly – with the right timing and diet – is essential for best results and fewer side effects.
Important Medical Advice
If you experience severe abdominal pain, persistent oily rectal discharge, signs of allergic reaction (rash, itching, swelling, difficulty breathing), or symptoms of pancreatitis (severe upper stomach pain spreading to back), stop taking orlistat and seek medical attention immediately.
How to Take Orlistat: Step-by-Step Usage Guide
Follow these steps to ensure you use orlistat safely and effectively:
- Consult your doctor: Before starting, ensure orlistat is suitable for you (see “Who Should Use” section).
- Read the patient information leaflet: Familiarise yourself with the product information (like the PIL you received).
- Take with fat‑containing meals: Swallow one 120mg capsule whole with a glass of water immediately before, during, or up to one hour after a main meal that contains fat.
- Skip if meal has no fat: If a meal contains no fat (e.g., only fruit or vegetables), you do not need to take a dose.
- Follow a reduced‑calorie diet: Your doctor will recommend a diet with around 30% of calories from fat, spread over three meals. Avoid high‑fat foods between meals.
- Take a multivitamin: Because orlistat may reduce absorption of fat‑soluble vitamins, take a multivitamin supplement once daily at bedtime (at least 2 hours after your last orlistat dose).
- Attend regular check‑ups: Your doctor will monitor your weight loss progress and may stop treatment if you haven’t lost enough weight after 12 weeks.
🗒️ Practical tip: Keep your capsules in the original blister pack to protect from light and moisture. Store below 25°C.
Dosage Guide for Orlistat 120mg
The standard dose is one 120mg capsule with each main meal containing fat. Here’s a quick reference:
| Meal type | Dose required | Example |
|---|---|---|
| Breakfast (contains fat) | Take 1 capsule | Eggs, toast with butter, full‑fat yogurt |
| Lunch (contains fat) | Take 1 capsule | Chicken sandwich with mayonnaise |
| Dinner (contains fat) | Take 1 capsule | Grilled salmon with olive oil |
| Snack or fat‑free meal | No dose needed | Apple, salad with no dressing |
Maximum daily dose is 360mg (three 120mg capsules). Do not take more than three capsules in 24 hours.
What if I miss a dose?
If you forget to take orlistat with a meal, and it’s still within one hour after finishing the meal, take the capsule as soon as you remember. If more than one hour has passed, skip that dose and take the next one with your next fat‑containing meal. Never double up.
What if I take too much?
Taking more than the prescribed dose may increase side effects (oily stools, abdominal discomfort). If you take an overdose, contact your doctor or pharmacist for advice.
Who Should Use Orlistat
Orlistat is suitable for adults (18 years and older) who:
- Have a body mass index (BMI) of 30 kg/m² or more (obese), or a BMI of 28 kg/m² or more with associated risk factors (e.g., type 2 diabetes, high blood pressure, high cholesterol).
- Have tried diet, exercise, and lifestyle changes but not achieved sufficient weight loss.
- Are committed to following a low‑fat, reduced‑calorie diet alongside the medication.
- Have discussed the treatment with a doctor and have no contraindications.
Orlistat is also used off‑label in some cases for weight maintenance after significant weight loss. Always follow your doctor’s advice.
Who Should NOT Use Orlistat
Do not take orlistat if any of the following apply:
- Allergy: You are allergic to orlistat or any of the ingredients (microcrystalline cellulose, sodium starch glycolate, silica, sodium lauril sulfate, gelatin, titanium dioxide, indigo carmine).
- Chronic malabsorption syndrome: A condition where your body cannot absorb nutrients properly.
- Cholestasis: A liver disorder where bile flow is reduced.
- Breastfeeding: Orlistat passes into breast milk and should not be used while breastfeeding.
- Pregnancy: Orlistat is not recommended during pregnancy because weight loss offers no benefit and safety is not established.
- Children and adolescents: Under 18 years, unless specifically prescribed by a specialist (rare).
- Taking ciclosporin: Co‑administration is not recommended unless closely monitored by a doctor.
- Taking acarbose: Orlistat is not recommended with acarbose (a diabetes medicine).
If you have kidney problems, tell your doctor – orlistat may increase the risk of kidney stones in those with chronic kidney disease.
Taking Orlistat With Food and Without Food
Orlistat works only in the presence of dietary fat. Therefore, when you take it matters:
With food (fat‑containing meals)
Take one capsule with each main meal that contains fat. The capsule should be swallowed whole with water. You can take it:
- Immediately before the meal,
- During the meal, or
- Up to one hour after the meal.
This timing ensures that orlistat is present in your gut when fat arrives, allowing it to block fat digestion.
Without food (fat‑free meals)
If a meal contains no fat (e.g., a salad with no oil, fruit, boiled vegetables without butter), orlistat has nothing to work on. In that case, you should skip the dose entirely. Taking it with a fat‑free meal will not provide any benefit and may increase the chance of missing a dose when you actually need it.
Between meals
Do not take orlistat between meals, as there is no fat to block and it may cause unnecessary gastrointestinal effects.
🗒️ Patient tip: Plan your meals so that you have three main meals with moderate fat content. Avoid high‑fat snacks; if you do eat a fatty snack, you would need an extra dose, but that’s not recommended – better to avoid the snack.
Special Conditions: Pregnancy, Breastfeeding and Other Considerations
Pregnancy
Orlistat is not recommended during pregnancy. Weight loss offers no potential benefit to a pregnant woman and may harm the fetus. If you become pregnant while taking orlistat, stop the medication and inform your doctor immediately.
Breastfeeding
It is unknown whether orlistat passes into human milk, but because of the potential for serious adverse reactions in nursing infants, breastfeeding is contraindicated during orlistat treatment. Do not breastfeed while taking orlistat.
Children and adolescents
Safety and effectiveness in patients under 18 years have not been established. Orlistat is not intended for use in children.
Elderly
No dose adjustment is needed for elderly patients, but they should be monitored for side effects and vitamin deficiencies.
Renal impairment
Patients with chronic kidney disease should use orlistat with caution, as there have been reports of kidney stones (oxalate nephropathy). Your doctor will assess the risks.
Hepatic impairment
Orlistat is contraindicated in cholestasis. For other liver conditions, use with caution and under medical supervision.
Drug interactions
Orlistat may interact with several medicines:
- Ciclosporin: Avoid concurrent use; if unavoidable, monitor ciclosporin levels closely.
- Warfarin (anticoagulants): Monitor INR, as weight loss and vitamin K absorption changes may affect clotting.
- Levothyroxine: Cases of hypothyroidism reported; separate doses by at least 4 hours.
- Amiodarone: Reduced absorption possible; monitor.
- Antiepileptics: Seizures have been reported; monitor seizure control.
- HIV medications, antidepressants: Consult your doctor.
Orlistat Usage FAQs
Can I take orlistat if I skip breakfast?
If you skip breakfast or have a fat‑free breakfast, do not take a dose. Only take orlistat with meals that contain fat.
What should I do if I experience oily stools?
Oily stools usually mean you’ve eaten too much fat. Stick to your low‑fat diet – the symptom should improve. If it persists, talk to your doctor.
Do I need to take orlistat forever?
No. Treatment usually continues as long as you are losing weight. After 12 weeks, if you haven’t lost at least 5% of your initial weight, your doctor may advise stopping.
Can I drink alcohol while taking orlistat?
Alcohol itself does not interact with orlistat, but alcoholic drinks can be high in calories and may hinder weight loss. Drink in moderation.
Is orlistat available over the counter?
In the UK, orlistat 60mg (Alli) is available over the counter; orlistat 120mg is a prescription‑only medicine. You must have a consultation with a doctor or pharmacist before starting.
Need a Prescription for Orlistat?
If you’re ready to start your weight loss journey with orlistat, our UK‑registered doctors can help. Complete a quick online consultation to see if orlistat is right for you.
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Medical Content Manager
Nabeel is a co-founder, and medical content manager of Chemist Doctor. He works closely with our medical team to ensure the information is accurate and up-to-date.
Medical Doctor
Dr. Feroz is a GMC-registered doctor and a medical reviewer at Chemist Doctor. He oversees acute condition and urgent care guidance.
Medical Director
Usman is a co-founder, and medical director of Chemist Doctor. He leads the organisation's strategic vision, bridging clinical and operational priorities.
Review Date: 23 February 2026
Next Review: 23 August 2026
Published on: 23 February 2026
Last Updated: 23 February 2026