The Science Behind Orlistat's Fat-Blocking Action
How Orlistat Blocks Fat Absorption
Orlistat works through a scientifically proven mechanism that targets fat digestion in your gut. It inhibits lipase enzymes responsible for breaking down dietary fat, preventing approximately one third of the fat you eat from being absorbed into your body. This unabsorbed fat passes naturally through your digestive system, reducing the calories absorbed from fatty foods.
Unlike stimulant-based weight loss medications that affect your brain, orlistat acts locally in your digestive system. It's not absorbed into your bloodstream in significant amounts, making its action targeted and specific to fat absorption.
Why This Mechanism Matters for Weight Loss
By blocking approximately one third of dietary fat absorption, orlistat can help create the calorie deficit needed for weight loss when combined with a reduced-calorie, lower-fat diet. Each gram of fat contains 9 calories, so reducing fat absorption can significantly impact your daily calorie intake.
Generic orlistat 120mg starts from £16.89 for a 2-week supply (£15.20 with EDM10), making it a cost-effective option. For those preferring the branded version, Xenical 120mg is available from £21.50, while Alli 60mg offers a lower-strength alternative from £28.99.
What to Expect When Orlistat Blocks Fat
The fat-blocking action of orlistat is directly related to your meal's fat content. When you eat a meal containing fat, orlistat prevents approximately one third of that fat from being digested and absorbed. This may result in gastrointestinal side effects, particularly if you eat high-fat meals, as the unabsorbed fat passes through your system.
Keeping your fat intake to approximately 15g per meal helps minimise side effects while allowing orlistat to work effectively. This is why orlistat must always be used alongside a reduced-calorie, lower-fat diet for optimal results and tolerability.
Comparing Your Options
All three products work through the same fat-blocking mechanism. Orlistat 120mg and Xenical 120mg contain identical active ingredients at the same dose, with generic orlistat offering significant savings. A 12-week supply of orlistat costs £86.39 with EDM10, compared to £116.09 for Xenical - saving over £29.
Alli 60mg contains half the dose, blocking a smaller proportion of dietary fat but often causing milder side effects. Your prescriber will help determine which option suits your individual circumstances following clinical assessment.
Getting Your Prescription Online
Understanding how orlistat blocks fat absorption is the first step - the next is accessing treatment through our regulated online service. Complete our clinical questionnaire, and a UK-licensed prescriber will review your suitability for treatment. If approved, your medication is dispensed by our GPhC-registered Leicester pharmacy and delivered discreetly to your address with next-day delivery available.
