The Science Behind Orlistat's Fat-Blocking Action
How Orlistat Blocks Fat Absorption
Orlistat works by inhibiting lipase enzymes in your digestive system. These enzymes normally break down dietary fat so it can be absorbed into your bloodstream. When orlistat blocks these enzymes, approximately one third of the fat you eat cannot be digested or absorbed. This unabsorbed fat passes naturally through your digestive system and is excreted from your body.
Why This Mechanism Matters for Weight Loss
By blocking approximately one third of dietary fat absorption, orlistat reduces the calories your body absorbs from meals. Fat contains 9 calories per gram - more than twice that of carbohydrates or protein. When combined with a reduced-calorie, lower-fat diet, this fat-blocking action may support weight management in adults with a BMI of 28-30 or above, subject to clinical assessment.
Orlistat vs Xenical vs Alli - Same Mechanism, Different Strengths
Generic orlistat 120mg (from £29.69 for 4 weeks with EDM10) and branded Xenical 120mg (£38.69 for 4 weeks with EDM10) contain identical active ingredients and work through the same fat-blocking mechanism. Alli 60mg (£26.09 for 4 weeks with EDM10) contains half the dose, blocking a smaller proportion of dietary fat. All three products work locally in your gut rather than being absorbed into your bloodstream in significant amounts.
What You Can Expect When Orlistat Works
When orlistat successfully blocks fat absorption, you may experience oily stools, increased bowel movements, or oily spotting - these are signs the medication is working. Keeping meals low in fat (approximately 15g per meal) helps minimise these effects while allowing the fat-blocking mechanism to work effectively. Most people find these effects reduce over time as their diet adapts.
Maximising Orlistat's Fat-Blocking Effect
Orlistat works best when taken with each main meal containing fat - one 120mg capsule three times daily for prescription strength, or one 60mg Alli capsule three times daily. The medication should be taken immediately before, during, or up to one hour after eating. If you skip a meal or eat a fat-free meal, you can skip that dose since there's no fat to block.
Why Understanding the Mechanism Helps Your Treatment
Knowing that orlistat blocks approximately one third of dietary fat - not all fat - helps set realistic expectations. The remaining two thirds of fat is still absorbed normally, which is why combining orlistat with a reduced-calorie, lower-fat diet is essential. This mechanism also explains why high-fat meals increase side effects - more unabsorbed fat passes through your system.
Start Your Orlistat Treatment Today
Now you understand how orlistat's fat-blocking mechanism works, you can make an informed decision about treatment. EverydayMeds offers orlistat 120mg from £86.39 for 12 weeks, Xenical from £116.09, or Alli 60mg from £116.99 - all with 10% off using code EDM10. Complete your online clinical assessment today for next day delivery from our GPhC-registered Leicester pharmacy.
