Semaglutide is cheaper. Tirzepatide produces more weight loss. The question isn't which costs less per month — it's which delivers more value per dollar spent. We ran the numbers.
Head-to-Head: SURMOUNT-5 Results
The SURMOUNT-5 trial (751 participants, 72 weeks) is the first randomized head-to-head comparison of semaglutide and tirzepatide for weight loss. Tirzepatide produced -20.2% mean weight change versus -13.7% for semaglutide. That's 47% more weight loss with tirzepatide — a clinically meaningful difference.
At the 15mg tirzepatide dose, 89-91% of participants achieved at least 5% weight loss, with 57% reaching 20% or more. For semaglutide at 2.4mg, approximately 70% lost 10%+, 50% reached 15%, and one-third hit 20%.
The Price Comparison
| Source | Semaglutide/mo | Tirzepatide/mo | Sema 12-Mo | Tirz 12-Mo |
|---|---|---|---|---|
| GobyMeds | $99 | $133 | $1,188 | $1,596 |
| Oak Longevity | $130 | $199 | $1,560 | $2,388 |
| Gala GLP-1 | $179 | $179 | $2,148 | $2,148 |
| Yucca Health | From $149 | From $258 | $1,788+ | $3,096+ |
| Care Bare Rx | From $169 | Available | $2,028+ | Varies |
| Embody | $149-299 | N/A | $3,541 | N/A |
| Wegovy self-pay | $199-349 | N/A | $3,588-4,188 | N/A |
| Zepbound self-pay | N/A | $299-449 | N/A | $3,588-5,388 |
| Insurance + card | $25 | $25 | $300 | $300 |
Cost-Per-Pound-Lost Analysis
For a 200-pound person, here's what each medication costs per pound of weight lost at the SURMOUNT-5 trial efficacy rates:
| Medication | Weight Loss (200lb person) | GobyMeds Annual | Cost per Pound Lost |
|---|---|---|---|
| Semaglutide | 27.4 lbs (13.7%) | $1,188 | $43/lb |
| Tirzepatide | 40.4 lbs (20.2%) | $1,596 | $39/lb |
| Sema (brand self-pay) | 27.4 lbs | $3,588 | $131/lb |
| Tirz (brand self-pay) | 40.4 lbs | $3,588 | $89/lb |
| Foundayo (oral) | 22-24 lbs (~11-12%) | $2,388 | $100-109/lb |
When Semaglutide Is Still the Right Choice
Despite tirzepatide's superior value-per-pound, semaglutide makes sense in several scenarios: your budget is the absolute primary constraint ($99 sema vs $133 tirz saves $408/year), you've tried tirzepatide and experienced intolerable GI side effects (some patients tolerate sema better), your provider doesn't offer tirzepatide, or you want the oral option (Wegovy tablet, no injectable tirzepatide pill exists yet).
Also note that a recent cost-effectiveness study published in April 2026 found tirzepatide was projected to deliver lower total costs and better long-term health outcomes than semaglutide for adults with obesity — reducing T2D cases by 70 per 1,000 patients and CVD cases by 10 per 1,000 patients compared to semaglutide.
The Dual-Agonist Advantage
Tirzepatide's superior efficacy comes from its dual mechanism: it activates both GLP-1 and GIP receptors, while semaglutide activates only GLP-1. The GIP receptor in fat cells appears to produce synergistic effects on fat mobilization and energy expenditure that explain the 47% greater weight loss. This isn't a marginal improvement — it's a fundamentally different pharmacological approach.
For patients who plateau on semaglutide, switching to tirzepatide may restart weight loss. The price premium for tirzepatide ($34/month more at GobyMeds) is trivial compared to the additional clinical benefit.