What is Orlistat?
Orlistat is a lipase inhibitor that reduces the absorption of fat from food in the intestine. About 30% of dietary fat is excreted undigested instead of being absorbed.
Orlistat is available in two strengths:
- 120 mg (prescription-only, as Xenical or as a generic)
- 60 mg (available without a prescription, as Alli or Orlistat Hexal)
It is one of the oldest medications for weight reduction and works differently from the new GLP-1 agonists: not on the brain, but in the intestine.
Active Ingredients & Mechanism of Action
Active ingredient: Orlistat
Orlistat inhibits gastrointestinal lipases – enzymes that break down dietary fat:
Mechanism:
- Binds to lipases in the stomach and small intestine
- Prevents the breakdown of triglycerides
- Fats that have not been broken down cannot be absorbed
- Approx. 30% of dietary fat is excreted
Result:
- Fewer calories absorbed from fat
- Weight loss with a calorie-reduced diet
- "Training effect": high-fat meals lead to unpleasant side effects
Who is it suitable for?
Orlistat is suitable for:
- Adults with a BMI ≥ 28 (60 mg without a prescription)
- Adults with a BMI ≥ 30, or with a BMI ≥ 28 and accompanying risk factors (120 mg, prescription-only)
- People who can/want to eat a reduced-fat diet
- As support for a calorie-reduced diet
Available Dosages
Without a prescription (Alli):
- 60 mg, 3x daily with meals
Prescription-only (Xenical):
- 120 mg, 3x daily with meals
How to Take
- One capsule immediately before, during or up to 1 hour after each main meal
- Only needed with meals that contain fat
- No more than 3x daily
- Take a multivitamin supplement in the evening (fat-soluble vitamins are also blocked)
Contraindications
- Chronic malabsorption
- Cholestasis (bile stasis)
- Pregnancy/breastfeeding
- Taking ciclosporin
- Taking warfarin or other oral anticoagulants (applies to 60 mg, with 120 mg monitor clotting values instead)
Possible Side Effects
Very common (especially with high-fat food):
- Fatty/oily stools
- Urgent need to have a bowel movement
- Oily spots on underwear
- Flatulence with discharge of stool
- More frequent bowel movements (common with 60 mg)
- Abdominal pain (common with 60 mg)
- Flatulence
Common:
- Incontinence
These side effects are a "training effect" – they occur mainly when the food eaten is too high in fat.
Frequently Asked Questions
In studies with 120 mg, participants lost on average 1.8 to 4.4 kg more than with diet alone, depending on the study. With 60 mg, participants lost on average 4.4 kg after 6 months, compared with 2.1 kg with diet alone. The effect is moderate, but significant with consistent use.
Then the side effects become more unpleasant (oily stools, diarrhea). Orlistat 'punishes' high-fat meals and in this way trains you to eat more healthily.
Yes, a multivitamin supplement containing fat-soluble vitamins (A, D, E, K) should be taken in the evening, as orlistat reduces their absorption.
Similar Medications
Is Orlistat right for you?
A licensed doctor will review your information and issue a prescription if suitable. Discreet and secure.
Important Notice
This information does not replace medical advice. If you have questions about your health or the suitability of this medication, please consult a doctor or pharmacist.
Important Safety Information
This service operates under German pharmaceutical law (HWG). For risks and side effects, read the package leaflet and consult your doctor or pharmacist. All medications are dispensed from a licensed pharmacy in Germany.