Key takeaways
Orlistat (Alli, Xenical) and semaglutide (Wegovy) are both medications used to help with weight loss in people with overweight or obesity. However, they belong to different medication classes and work in different ways. Orlistat is a lipase inhibitor that blocks the absorption of fats from your diet, while semaglutide is a glucagon-like peptide-1 (GLP-1) receptoragonist that helps control your appetite and makes you feel full sooner. Orlistat is available both over-the-counter (as Alli) and by prescription (as Xenical), and you take it three times a day with meals. Semaglutide, on the other hand, is a prescription-only medication that you inject under your skin once a week. Orlistat can cause side effects like oily stools and gas, while semaglutide may cause nausea, vomiting, and diarrhea. Additionally, semaglutide has a potential risk for thyroid cancer. Orlistat can interact with medications like levothyroxine (Synthroid, Levoxyl, Tirosint) and warfarin (Coumadin, Jantoven); semaglutide can affect how these medications are absorbed and also had an increased risk of low blood sugar when combined with other diabetes medications.
