Ready to Start? Understanding the Mechanism Builds Confidence
How Orlistat Blocks Fat Absorption
Orlistat works through a straightforward mechanism that targets fat digestion in your gut. The active ingredient inhibits lipase enzymes - proteins responsible for breaking down dietary fat. When these enzymes are blocked, approximately one third of the fat you eat cannot be digested or absorbed into your body. This unabsorbed fat passes naturally through your digestive system and is excreted.
Why This Mechanism Is Effective for Weight Management
By preventing approximately one third of dietary fat absorption, orlistat reduces the calorie content of meals containing fat. Since fat provides 9 calories per gram - more than twice that of carbohydrates or protein - this reduction can significantly impact overall calorie intake. Generic orlistat 120mg (£32.99 for 4 weeks, £29.69 with EDM10) and branded Xenical (£42.99 for 4 weeks) work identically through this proven mechanism.
Local Action - Minimal Systemic Absorption
Unlike medications that work through the brain or bloodstream, orlistat acts locally in your digestive system. Very little orlistat is absorbed into your bloodstream, meaning the fat-blocking action occurs specifically where dietary fat is processed. This targeted approach helps explain why most side effects are gastrointestinal and directly related to unabsorbed fat content.
What Happens to Blocked Fat
The approximately one third of dietary fat that orlistat blocks doesn't disappear - it passes through your body unchanged. This is why maintaining a lower-fat diet (around 15g fat per meal) is essential. High-fat meals result in more unabsorbed fat, leading to the characteristic oily stools and gastrointestinal effects that signal the medication is working.
Dosing That Matches Your Eating Pattern
Orlistat's mechanism requires taking one capsule with each main meal containing fat - typically three times daily. If you skip a meal or eat a fat-free meal, you can skip that dose since there's no fat to block. This flexible dosing matches how the mechanism works. Our 84-capsule packs (£32.99 orlistat, £42.99 Xenical) provide exactly 4 weeks of three-times-daily dosing.
Lower-Strength Option: How Alli 60mg Works
Alli contains half the dose of prescription-strength orlistat, working through the same fat-blocking mechanism but with reduced potency. At 60mg, it blocks a smaller proportion of dietary fat compared to the 120mg prescription versions. Alli 60mg costs £28.99 for 4 weeks (£26.09 with EDM10), offering an alternative for those preferring lower-strength treatment.
Clinical Proof the Mechanism Works
The fat-blocking mechanism has been extensively studied and proven effective when combined with a reduced-calorie, lower-fat diet. UK prescribers rely on this established mechanism when assessing treatment suitability. Following online clinical assessment through EverydayMeds, qualified prescribers can determine whether orlistat's mechanism suits your weight management goals.
