Lipase Inhibitor
A prescription treatment that reduces how much dietary fat the body absorbs from food, used as part of medically supervised weight management.
Plain English
Patient-Friendly Explanation
A lipase inhibitor is a medication that blocks about a third of the fat you eat from being absorbed, so the fat passes out of the body instead of being stored. It works only if you keep fat in meals modest — very fatty food causes oily bowel movements. Weight loss is modest but steady when combined with a lower-calorie diet.
Medical
Clinical Definition
Lipase inhibitors such as orlistat act locally in the gut lumen by irreversibly inhibiting pancreatic and gastric lipases, reducing dietary fat absorption by approximately 30%. In randomised trials, orlistat plus lifestyle produces placebo-subtracted weight loss of roughly 3–4 kg at one year and reduces progression to type 2 diabetes in people with impaired glucose tolerance. Adverse effects are mechanism-related: oily spotting, steatorrhoea, faecal urgency and flatulence, particularly when dietary fat exceeds about 30% of calories. Because fat-soluble vitamins (A, D, E, K) may be malabsorbed, a multivitamin containing them is recommended at a separate time of day.
Key Insight
Why It Matters
This older class still has a place for people who prefer a non-injectable option, but the side effects punish high-fat meals — which is exactly the point. We counsel the diet alongside the drug so the two work together.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: August 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.
