The two leading FDA-approved weight-management drugs, compared side by side.
| Attribute | Semaglutide FDA-approved | Tirzepatide FDA-approved |
|---|---|---|
| Class / type | GLP-1 receptor agonist | Dual GIP / GLP-1 agonist |
| How it works | Mimics incretin GLP-1: boosts glucose-dependent insulin, suppresses glucagon, slows gastric emptying, reduces appetite centrally. | Activates both GIP and GLP-1 receptors: raises glucose-dependent insulin, lowers glucagon, slows gastric emptying, strongly suppresses appetite. |
| Known / used for | Type 2 diabetes (Ozempic/Rybelsus), weight management (Wegovy), CV risk reduction, MASH. | Type 2 diabetes (Mounjaro), weight management (Zepbound), obstructive sleep apnea with obesity (Zepbound). |
| Positives | ~15% weight loss in obesity trials; proven A1c lowering; reduced cardiovascular events; oral option exists. | Among the most effective approved agents (~20%+ weight loss); strong A1c reduction; added OSA indication. |
| Negatives & risks | GI effects (nausea, vomiting, diarrhea) worst at start; rare pancreatitis, gallbladder disease, gastroparesis; boxed warning for thyroid C-cell tumors (rodent data). | GI effects (nausea, diarrhea, vomiting, constipation); injection-site reactions, fatigue, reported hair loss; boxed thyroid C-cell tumor warning; rare pancreatitis. |
| Legal status (Jul 2026) | FDA-approved prescription drug (Ozempic, Rybelsus, Wegovy). Gray-market 'research' vials are NOT the approved product. | FDA-approved prescription drug (Mounjaro, Zepbound). Gray-market 'research' vials are NOT the approved product. |