Semaglutide vs Tirzepatide: Which Wins for Weight Loss?
Semaglutide and Tirzepatide are both weekly injectable weight loss medications — but they work differently, produce different results, and carry different price tags. Here is the honest, data-driven comparison most clinics will not give you.
The core difference
Semaglutide is a GLP-1 receptor agonist. Tirzepatide is a dual GIP/GLP-1 receptor agonist. That additional GIP receptor mechanism is the key differentiator — it produces synergistic metabolic effects that result in substantially greater weight loss, with comparable or better tolerability.
The headline number: In the SURMOUNT-5 trial — the first direct head-to-head comparison — Tirzepatide produced 47% more weight loss than Semaglutide at comparable doses (20.2% vs 13.7% of body weight). This is not a marginal difference. For weight loss specifically, Tirzepatide is clinically superior.
Semaglutide: overview
Semaglutide (Ozempic for diabetes, Wegovy for obesity) was the first major GLP-1 agonist to demonstrate remarkable weight loss in clinical trials, producing average reductions of 12–15% of body weight in the STEP trials. It works by activating GLP-1 receptors in the brain and gut, reducing appetite, slowing gastric emptying, and improving insulin secretion.
Semaglutide has a longer track record, broader insurance coverage in some plans, and is more widely available through both brand-name and compounding pharmacy channels. Read our full Semaglutide guide and dosage guide.
Tirzepatide: overview
Tirzepatide (Mounjaro for diabetes, Zepbound for obesity) adds GIP receptor agonism to the GLP-1 mechanism, creating synergistic effects on fat metabolism, appetite suppression, and insulin sensitivity. The SURMOUNT trials showed average weight loss of 20–22% of body weight — the highest ever recorded for a non-surgical weight loss medication.
Tirzepatide also appears to preferentially reduce fat mass while preserving lean muscle — an important advantage for long-term metabolic health. Read our full Tirzepatide guide.
Side by side comparison
| Feature | Semaglutide | Tirzepatide |
|---|---|---|
| Mechanism | GLP-1 agonist only | Dual GIP + GLP-1 agonist |
| Average weight loss (clinical trials) | 12–15% of body weight | 20–22% of body weight |
| Head-to-head result | — | 47% more weight loss than Sema |
| FDA approval | Yes (Ozempic/Wegovy) | Yes (Mounjaro/Zepbound) |
| Dosing frequency | Once weekly | Once weekly |
| GI side effects | Moderate (nausea, diarrhea) | Slightly lower (GIP dampens GI effects) |
| Starting dose | 0.25 mg/week | 2.5 mg/week |
| Maximum dose | 2.4 mg/week (Wegovy) | 15 mg/week |
| Monthly cost (brand) | $900–$1,400 | $900–$1,400 |
| Monthly cost (compounded) | $150–$350 | $150–$400 |
| Best for | Moderate weight loss, established insurance coverage | Maximum weight loss, metabolic syndrome |
Cost comparison
Brand-name pricing for both medications is roughly comparable — $900–$1,400 per month without insurance. With insurance, coverage varies significantly. Compounded versions (available during shortage periods or for cost-conscious patients) run $150–$400 per month depending on the provider and dose.
Given that Tirzepatide produces substantially more weight loss per dollar spent, the cost-per-pound-lost math strongly favors Tirzepatide for most patients prioritizing maximum results. The decision ultimately comes down to your insurance situation, access to compounded versions, and how you personally tolerate each medication.
Note: Both medications require a prescription from a licensed physician in the US. FDA shortage status affects compounded availability — your provider can advise on current options.
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