Orlistat:
Orlistat is a weight loss medication that works by blocking the absorption of dietary fat in the digestive system. It inhibits the action of pancreatic and gastric lipases, the enzymes responsible for breaking down fat in the intestine. As a result, about 25–30% of the fat consumed in a meal passes through the body undigested, reducing overall calorie intake. Orlistat is available by prescription under the brand name Xenical and in a lower dose over-the-counter as Alli. Unlike GLP-1 medications like Ozempic and Wegovy, Orlistat works locally in the gut and does not affect appetite or blood sugar regulation.

Orlistat is typically used alongside a reduced-calorie, low-fat diet and an exercise program to help adults with obesity, or those who are overweight with other risk factors, lose weight. Common side effects include gastrointestinal issues like oily stools, flatulence, and frequent bowel movements, particularly if too much fat is consumed. While effective for some, its tolerability can be a limiting factor. It is also important to take a daily multivitamin when using Orlistat, as it can reduce the absorption of fat-soluble vitamins (A, D, E, and K).