Orlistat
A fat-absorption blocker (Xenical, Alli) that reduces dietary fat uptake by about a third — modest results, notorious GI effects.
Orlistat takes the only non-hormonal path on this list: it inhibits pancreatic lipase in the gut, so roughly 30% of dietary fat passes through undigested. It is available by prescription (Xenical) and over the counter at half dose (Alli), making it one of the few weight medications sold without a prescription.
Average placebo-adjusted loss is about 3%, and adherence is limited by its signature GI effects — oily stools and urgency whenever a meal exceeds the fat budget, which functions as aversive training more than pharmacology. It suits patients wanting a non-systemic, non-stimulant option and willing to eat low-fat; most others find modern GLP-1 therapy both more effective and easier to live with.
This glossary entry is general information, not medical advice, and is written to be consistent with FDA prescribing information and primary trial publications as of its last review. Always consult a licensed healthcare provider for personal medical decisions.
Questions about Orlistat? Ask a doctor free.
A licensed doctor can apply this to your health history in a free telehealth consultation — booking takes about two minutes, with programs from $149/month. You're only charged after approval.
Book an Appointment