Two drugs dominate the prescription weight loss market: Wegovy (semaglutide) and Zepbound (tirzepatide). Both FDA-approved for chronic weight management.
Mechanism Difference
Wegovy: Pure GLP-1 agonist — reduces appetite and slows gastric emptying.
Zepbound: Dual GLP-1 + GIP agonist — GIP may amplify GLP-1 effects and improve insulin sensitivity.
Clinical Weight Loss Results
- Wegovy (STEP 1): Average 14.9% body weight loss over 68 weeks
- Zepbound (SURMOUNT-1): Average 20.9% body weight loss over 72 weeks
The SURMOUNT-5 direct head-to-head trial: tirzepatide produced 47% more weight loss than semaglutide (20.2% vs 13.7%). Zepbound wins on efficacy.
Side Effects
Both produce similar GI side effects: nausea, diarrhoea, vomiting. Some evidence suggests Zepbound's GIP component may reduce nausea, but individual response varies.
2025 Cost (Without US Insurance)
- Wegovy: ~$1,300-1,400/month
- Zepbound: ~$1,000-1,100/month
Zepbound is currently cheaper and more effective — a rare win-win. Both have manufacturer savings programmes.
Which to Choose?
Clinical data favours Zepbound for efficacy and cost. But individual response varies, and your physician's judgement, insurance coverage, and availability should all factor in.