Ozempic vs Mounjaro
A comprehensive comparison of two leading GLP-1 and GIP receptor agonist medications for weight loss and diabetes management.
Last updated March 2026 · Read our methodology
Quick Answer
Ozempic (semaglutide) is a GLP-1 receptor agonist approved for type 2 diabetes and weight loss (as Wegovy). It stimulates insulin release, slows gastric emptying, and reduces appetite. Mounjaro (tirzepatide) is a dual GLP-1/GIP receptor agonist offering slightly stronger weight loss effects (~20–22% vs 15–18% for semaglutide). Mounjaro is approved for diabetes and weight loss (as Zepbound).
Choose Ozempic/Wegovy if: You have type 2 diabetes, prefer a proven single-mechanism therapy, or have insurance coverage. Choose Mounjaro/Zepbound if: Maximum weight loss is your goal and you tolerate GI side effects well.
Side-by-Side Comparison Table
| Feature | Ozempic / Wegovy (Semaglutide) | Mounjaro / Zepbound (Tirzepatide) |
|---|---|---|
| Mechanism | GLP-1 receptor agonist | Dual GLP-1 / GIP receptor agonist |
| Average Weight Loss | ~15% body weight (STEP trials, 68 weeks) | ~21% body weight (SURMOUNT trials, 72 weeks) |
| Head-to-Head Result | 13.7% (SURMOUNT-5) | 20.2% (SURMOUNT-5) — 47% more weight loss |
| FDA Approvals | Type 2 diabetes (Ozempic), weight loss (Wegovy), cardiovascular risk reduction | Type 2 diabetes (Mounjaro), weight loss (Zepbound), obstructive sleep apnea |
| Dosing | Weekly injection; 0.25 mg → up to 2.4 mg over ~16–20 weeks | Weekly injection; 2.5 mg → up to 15 mg over ~20 weeks |
| Nausea Rate | ~44% (typically resolves within days) | ~22–29% (dose-dependent) |
| List Price | $1,027–$1,349/month without insurance | $1,079–$1,086/month without insurance |
| With Insurance | $25–$299/month (plan-dependent); Wegovy weight-loss coverage limited | $25/month possible with savings card; Zepbound weight-loss coverage limited |
| Supply Status (2026) | Stable; FDA resolved shortage Feb 2025 | Stable; FDA resolved shortage Oct 2024 |
How They Work: GLP-1 vs Dual GLP-1/GIP
Ozempic and Wegovy contain semaglutide, which mimics the GLP-1 hormone your gut releases after eating. It slows gastric emptying, reduces appetite, and improves insulin sensitivity — a single-target approach with over a decade of clinical data behind it.
Mounjaro and Zepbound contain tirzepatide, which activates both the GLP-1 and GIP receptors. This dual mechanism amplifies the appetite-suppressing and metabolic effects beyond what GLP-1 alone can achieve, which is why tirzepatide consistently shows higher weight-loss numbers in clinical trials.
Clinical context: The SURMOUNT-5 trial directly compared the two drugs head-to-head. Patients on tirzepatide lost 20.2% of body weight versus 13.7% on semaglutide — a clinically meaningful difference that helped establish tirzepatide as the more potent weight-loss medication.
When Ozempic or Wegovy May Be the Better Choice
Semaglutide has the longest track record of any GLP-1 for weight loss, and it remains the right medication for many patients. Consider Ozempic or Wegovy if you:
- Have type 2 diabetes and cardiovascular concerns. Semaglutide has FDA approval for cardiovascular risk reduction — tirzepatide does not (yet). The SELECT trial showed a 20% reduction in major cardiovascular events.
- Have better insurance coverage for semaglutide. As the older drug, Ozempic and Wegovy appear on more formularies. Many insurers cover Ozempic for diabetes; Wegovy coverage is growing but still limited for weight loss alone.
- Want a well-studied safety profile. Semaglutide has been prescribed since 2017, giving clinicians nearly a decade of real-world safety data. Tirzepatide was approved in 2022.
- Are sensitive to GI side effects. While nausea rates are higher at the full dose, semaglutide's slower titration schedule (0.25 mg start) gives your body more time to adjust compared to tirzepatide's starting dose of 2.5 mg.
- Need an oral option. Rybelsus offers semaglutide in pill form for patients who prefer not to inject. Tirzepatide is injection-only.
When Mounjaro or Zepbound May Be the Better Choice
Tirzepatide is the newer, more potent option and has become the preferred choice for patients whose primary goal is maximum weight loss. Consider Mounjaro or Zepbound if you:
- Prioritize maximum weight loss. At the 15 mg dose, tirzepatide delivered 22.5% body weight reduction in SURMOUNT-1 — the highest of any approved GLP-1 therapy. Nearly 40% of participants lost over 25% of their body weight.
- Have obstructive sleep apnea. Zepbound received FDA approval for moderate-to-severe OSA in December 2024 — a unique indication no semaglutide product currently holds.
- Plateaued on semaglutide. Some patients who stop losing weight on Ozempic or Wegovy see renewed progress after switching to tirzepatide's dual-receptor mechanism.
- Tolerate GI side effects well. Tirzepatide's nausea rates are actually lower than semaglutide in some trials (22% vs 44%), though this varies by dose and study design.
- Can access Lilly's self-pay pricing. LillyDirect offers tirzepatide vials at $299–$499/month for self-pay patients — competitive with or cheaper than brand-name semaglutide for many people.
Important caveat: Tirzepatide does not yet have FDA approval for cardiovascular risk reduction. If heart disease prevention is a primary goal alongside weight loss, semaglutide (Wegovy) remains the evidence-backed choice for that specific indication.
Cost Comparison
Ozempic/Wegovy (semaglutide): List price runs $1,027–$1,349/month. With commercial insurance, copays range from $25 to $299/month depending on your plan and indication. Novo Nordisk offers savings programs for eligible patients. Medicare covers Ozempic for diabetes but generally does not cover Wegovy for weight loss.
Mounjaro/Zepbound (tirzepatide): List price runs $1,079–$1,086/month. Lilly's savings card can bring costs to $25/month for commercially insured patients (capped at $463/month). Self-pay patients can order vials through LillyDirect at $299–$499/month. Medicare covers Mounjaro for diabetes and Zepbound for sleep apnea.
Coverage for weight loss specifically remains a challenge for both drugs. As of 2026, major insurers continue to restrict or drop weight-loss coverage, pushing many patients toward self-pay or compounded alternatives — though compounded versions of both drugs have faced FDA crackdowns.
Side Effects Compared
Both medications cause similar gastrointestinal side effects, especially during dose escalation. The good news: most are mild to moderate and resolve within the first few weeks at each dose level.
Semaglutide side effect rates (2.4 mg dose): nausea 44%, diarrhea 30%, vomiting 25%, constipation 24%. Over 98% of GI events were classified as mild to moderate, and the median duration of nausea was about 8 days.
Tirzepatide side effect rates vary by dose: nausea 18–29%, diarrhea 17–23%, vomiting ~10%. The side-effect profile is broadly similar to semaglutide but with somewhat lower nausea rates in some trials.
Discontinuation due to side effects runs about 4–7% for both drugs — meaning the vast majority of patients are able to continue treatment after the adjustment period.
The Bottom Line
Tirzepatide (Mounjaro/Zepbound) wins for: Maximum weight loss, dual-mechanism potency, sleep apnea treatment, and potentially lower nausea at equivalent efficacy.
Semaglutide (Ozempic/Wegovy) wins for: Cardiovascular risk reduction, longer safety track record, broader insurance coverage, oral dosing option (Rybelsus), and more real-world prescribing data.
Neither drug is objectively "better" — the right choice depends on your health goals, insurance situation, and how your body responds. Many patients who start on one eventually try the other. Talk with your prescriber about which fits your specific clinical picture, and don't hesitate to switch if your first choice isn't delivering the results you expect.
References
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