Ozempic (semaglutide)
GLP-1
monoagonist · FDA 2017 · ~7-day half-life
Mounjaro (tirzepatide)
GLP-1 + GIP
dual agonist · FDA 2022 · ~5-day half-life
Both FDA-approved for type 2 diabetes. Head-to-head data from SURPASS-2 (1,879 patients, 40 weeks) favors Mounjaro on blood sugar and weight. Ozempic leads on cardiovascular outcomes. See full comparison below.
Key Takeaways
- Ozempic vs Mounjaro is a cross-molecule T2D comparison: Ozempic contains semaglutide (GLP-1 monoagonist); Mounjaro contains tirzepatide (GLP-1 + GIP dual agonist)
- In SURPASS-2, the only head-to-head trial, Mounjaro 15 mg reduced HbA1c by 2.30 percentage points vs 1.86 for Ozempic 1 mg, and produced 5.5 kg more weight loss
- Ozempic (semaglutide) has a proven cardiovascular benefit: the SELECT trial showed a 20% MACE reduction in over 17,000 patients with obesity and established CVD
- Both share the same GI side effect profile; SURPASS-2 found comparable nausea rates (17-22% vs ~18%)
- For a deeper molecular comparison including mechanism science, see the full molecular comparison of tirzepatide vs semaglutide
-2.30%
Mounjaro 15 mg HbA1c reduction (SURPASS-2)
-1.86%
Ozempic 1 mg HbA1c reduction (SURPASS-2)
5.5 kg
More weight loss with Mounjaro 15 mg vs Ozempic 1 mg
-20%
MACE reduction with semaglutide (SELECT trial, 2023)
Choosing between Ozempic vs Mounjaro for type 2 diabetes comes down to three things: blood sugar control, cardiovascular risk, and pen preference. Both are once-weekly injections. Both reduce HbA1c meaningfully. Both cause similar GI side effects. The differences matter clinically.
Ozempic (semaglutide, Novo Nordisk) is a GLP-1 receptor agonist approved in 2017. Mounjaro (tirzepatide, Eli Lilly) adds a second hormone pathway, GIP, making it a dual agonist approved in May 2022. In SURPASS-2, the only head-to-head randomized trial, all three Mounjaro doses outperformed Ozempic 1 mg on both HbA1c reduction and weight loss. Ozempic counters with the SELECT trial, a cardiovascular outcomes study showing a 20% reduction in major cardiac events.
This article covers the brand-level T2D comparison. For the full molecular mechanism science, see our tirzepatide vs semaglutide molecular comparison. For Mounjaro's obesity indication, see the tirzepatide hub.
Ozempic vs Mounjaro: Quick Comparison
The table below covers the key dimensions for T2D patients. Mounjaro superior values are highlighted in teal; Ozempic advantages in blue.
| Feature | Ozempic (semaglutide) | Mounjaro (tirzepatide) |
|---|---|---|
| Molecule | Semaglutide | Tirzepatide |
| Manufacturer | Novo Nordisk | Eli Lilly |
| Mechanism | GLP-1 receptor agonist (monoagonist) | Dual agonist (GLP-1 + GIP) |
| FDA T2D Approval | 2017 | May 2022 |
| Half-life | Approximately 7 days | Approximately 5 days |
| Starting dose (T2D) | 0.25 mg/week | 2.5 mg/week |
| Max T2D dose | 2.0 mg (1.0 mg standard trial ceiling) | 15 mg |
| Pen type | Dial-a-dose pen | Auto-injector (hidden needle) |
| SURPASS-2 HbA1c reduction | -1.86 pp (1 mg arm) | -2.30 pp (15 mg arm) |
| SURPASS-2 weight difference | Reference arm | 5.5 kg more (15 mg vs 1 mg sema) |
| Proven CV benefit (MACE) | Yes (SELECT 2023, -20% MACE) | Data emerging (CVOT ongoing) |
| List price (approx.) | ~$900-$1,100/month | ~$900-$1,100/month |
The core difference in one sentence
Mounjaro (tirzepatide, Eli Lilly) activates both GIP and GLP-1 receptors; Ozempic (semaglutide, Novo Nordisk) activates GLP-1 only. Both are once-weekly subcutaneous injections FDA-approved for type 2 diabetes, and both showed statistically significant superiority over placebo in their respective approval trials.
Different Drugs, Different Mechanisms
Both medications mimic natural gut hormones. Mounjaro targets one more receptor than Ozempic. That extra pathway produces measurable differences in insulin sensitivity, appetite, and fat metabolism.
Ozempic (semaglutide): GLP-1 monoagonist
Ozempic was developed by Novo Nordisk and received FDA approval for type 2 diabetes in 2017. It activates GLP-1 receptors, mimicking the gut hormone that:
- Slows gastric emptying, reducing post-meal glucose spikes
- Suppresses appetite via central nervous system signaling
- Stimulates insulin release when blood sugar is elevated
- Suppresses glucagon, reducing hepatic glucose output
Half-life: approximately 7 days. Max T2D dose: 2.0 mg, with 1.0 mg the standard ceiling used in T2D trials including the SURPASS-2 comparator arm. The dial-a-dose pen allows flexibility across dose steps.
Mounjaro (tirzepatide): GIP + GLP-1 dual agonist
Mounjaro was developed by Eli Lilly and received FDA approval for type 2 diabetes in May 2022. It activates both GLP-1 and GIP receptors. GIP adds:
- Enhanced insulin sensitivity in muscle and fat tissue
- Direct effects on adipose tissue that may amplify fat loss
- Possible synergy with GLP-1 for stronger appetite suppression at lower absolute doses of each agonist
Half-life: approximately 5 days. Max T2D dose: 15 mg. Pre-set auto-injector pens with a hidden needle, one pen per dose level. For the weight loss indication, Lilly markets the same molecule as Zepbound; this article focuses on Mounjaro's T2D indication.
SURPASS-2: The Only Head-to-Head Trial
SURPASS-2 is the landmark randomized trial that directly compared tirzepatide against semaglutide in 1,879 patients with type 2 diabetes over 40 weeks. Published in the New England Journal of Medicine in 2021, it remains the only head-to-head evidence base for this comparison.
The study enrolled adults with type 2 diabetes and mean HbA1c of 8.28%, mean age 56.6 years, on background metformin therapy. Participants were randomized to tirzepatide 5 mg, 10 mg, or 15 mg once weekly, or semaglutide 1.0 mg once weekly.
HbA1c results (blood sugar control)
| Treatment arm | HbA1c reduction (pp) | vs Semaglutide 1 mg |
|---|---|---|
| Semaglutide 1 mg (Ozempic) | -1.86 | Reference |
| Tirzepatide 5 mg (Mounjaro) | -2.01 | p=0.02 vs semaglutide |
| Tirzepatide 10 mg (Mounjaro) | -2.24 | p<0.001 vs semaglutide |
| Tirzepatide 15 mg (Mounjaro) | -2.30 | p<0.001 vs semaglutide |
All three tirzepatide doses achieved statistically significant superiority over semaglutide 1 mg. The 15 mg dose produced a 0.44 percentage point greater reduction in HbA1c.
Weight loss results
SURPASS-2 reported weight results as treatment differences compared to semaglutide 1 mg, not as absolute percentage changes. Tirzepatide produced greater weight loss at every dose:
| Tirzepatide dose | Additional weight loss vs semaglutide 1 mg |
|---|---|
| 5 mg | -1.9 kg more |
| 10 mg | -3.6 kg more |
| 15 mg | -5.5 kg more |
For obesity-trial context using the weight-loss indication formulations: tirzepatide 15 mg produced 20.9% body weight loss at 72 weeks in SURMOUNT-1, while semaglutide 2.4 mg produced 14.9% at 68 weeks in STEP 1. These are different trials, different populations, and different doses from SURPASS-2.
Important Limitation of SURPASS-2
The semaglutide comparator in SURPASS-2 was 1.0 mg, the standard T2D dose, not the 2.4 mg Wegovy obesity dose. This means the comparison was designed for T2D-indication-to-T2D-indication equivalency. Tirzepatide still achieved statistically significant superiority at all three doses in this setting.
SURPASS-2 enrolled T2D patients, not a pure obesity population. Results may not fully generalize to people without diabetes. Tirzepatide's superiority was statistically robust at all three doses regardless.
Plan Your Dosing Schedule
Use the free GLP3Planner calculators to visualize drug levels and build a titration plan for either medication.
Dosing and Titration Comparison
Both are once-weekly subcutaneous injections with gradual escalation schedules that span roughly five months to reach the maximum dose. The pen types differ. Mounjaro uses pre-set auto-injectors with a hidden needle, one pen per dose strength. Ozempic uses a dial-a-dose pen where you select the dose yourself.
Mounjaro titration (T2D indication)
| Phase | Dose (weekly) | Duration |
|---|---|---|
| Start | 2.5 mg | 4 weeks |
| Escalation 1 | 5 mg | 4 weeks |
| Escalation 2 | 7.5 mg | 4 weeks |
| Escalation 3 | 10 mg | 4 weeks |
| Escalation 4 | 12.5 mg | 4 weeks |
| Maximum | 15 mg | Maintenance |
Plan your full Mounjaro titration schedule with the Mounjaro calculator. For a printable reference, see the tirzepatide dosing guide.
Ozempic titration (T2D indication)
| Phase | Dose (weekly) | Duration |
|---|---|---|
| Start | 0.25 mg | 4 weeks |
| Escalation 1 | 0.5 mg | 4 weeks |
| Escalation 2 | 1.0 mg | 4 weeks (standard T2D ceiling) |
| Extended (if needed) | 2.0 mg | Approved max for T2D indication |
Plan your Ozempic titration with the Ozempic calculator. For full protocols, see the semaglutide dosing guide.
Side Effects: Ozempic vs Mounjaro in SURPASS-2
SURPASS-2 compared both drugs under identical trial conditions, so it's the cleanest head-to-head side effect data we have. The overall GI profile was similar between groups.
Doctor Mike Hansen (MD) covers Ozempic vs Mounjaro head-to-head. 749K views.
Shared GI side effects
| Side effect | Mounjaro (tirzepatide, SURPASS-2) | Ozempic (sema 1 mg, SURPASS-2) |
|---|---|---|
| Nausea | 17-22% across doses | ~18% |
| Diarrhea | Slightly higher vs semaglutide | Lower than tirzepatide |
| Constipation | Comparable | Comparable |
| Vomiting | Comparable | Comparable |
| Peak timing | First 4-8 weeks of each dose escalation; improves at stable dose | |
Where they differ on side effects
SURPASS-2 data suggests Mounjaro causes slightly more diarrhea; Ozempic slightly more nausea at comparable doses. Both share the same class-level serious adverse event warnings: rare pancreatitis (seek immediate care for severe abdominal pain), thyroid C-cell tumors in rodents (black box warning; avoid if you have a personal or family history of medullary thyroid carcinoma or MEN-2), and dehydration risk from persistent GI symptoms.
For the full side effect profile of Mounjaro, see tirzepatide side effects.
Managing GI Side Effects
- Eat smaller, more frequent meals during dose escalation
- Avoid fatty and greasy foods for the first few weeks at each dose step
- Stay well hydrated throughout treatment
- Talk to your prescriber about delaying titration if symptoms are severe
Free calculators for both medications. No account needed.
Cardiovascular Outcomes: Ozempic's Proven Edge
For T2D patients with existing heart disease, this is the part of the comparison that matters most clinically.
Ozempic (semaglutide): SELECT trial, 2023
The SELECT trial (NEJM 2023) enrolled over 17,000 patients with obesity and established cardiovascular disease but without type 2 diabetes. It demonstrated a 20% reduction in major adverse cardiovascular events (MACE) including heart attack and stroke with semaglutide 2.4 mg, making it the first weight-loss medication to demonstrate a cardiovascular mortality benefit in a dedicated outcome trial.
Mounjaro (tirzepatide): cardiovascular data still emerging
Tirzepatide's cardiovascular safety profile is considered favorable based on SURPASS-2 and other SURPASS trials, but a dedicated cardiovascular outcomes trial (SURMOUNT-CVOT) is ongoing. Tirzepatide does not yet have a completed cardiovascular outcomes trial showing a MACE reduction comparable to SELECT. For T2D patients with high cardiac risk, this is a meaningful clinical distinction when choosing between the two medications.
SELECT used semaglutide 2.4 mg (the Wegovy obesity dose) in a population without diabetes. Ozempic's approved 1.0 mg T2D dose has its own cardiovascular data: SUSTAIN-6 (Marso et al., NEJM 2016) showed a 26% relative risk reduction in cardiovascular events in T2D patients. Both trials point to semaglutide's cardiac advantages. SELECT is larger and more recent.
Cost and Insurance
Both Ozempic and Mounjaro are brand-name medications with similar list prices, typically in the $900-$1,100 per month range without insurance. Prices fluctuate with manufacturer savings programs, formulary changes, and compounding pharmacy availability; do not rely on a single figure.
- T2D indication for both: Both Ozempic and Mounjaro are approved for type 2 diabetes, giving them better formulary access than weight-loss-only indications in many insurance plans
- Savings cards: Novo Nordisk and Eli Lilly offer manufacturer savings cards that can reduce monthly cost significantly for eligible commercially insured patients
- Compounded versions: Compounded semaglutide and tirzepatide have been available through 503A/503B pharmacies, though the FDA shortage-list designation has been changing. Consult your prescriber about current legal status in your region
- Switching coverage: If your plan covers one but not the other, that coverage decision may be the practical answer to the "which one" question
For detailed Mounjaro pricing information, see tirzepatide weight loss and cost overview.
Which Should You Choose? (Decision Framework)
The decision between Ozempic and Mounjaro is a clinical one. Work through these questions with your prescriber, not as a self-prescribing checklist.
| Decision point | Ozempic | Mounjaro |
|---|---|---|
| Blood sugar control (T2D) | Strong (SURPASS-2: -1.86 pp) | Superior (SURPASS-2: -2.30 pp) |
| Weight loss priority | Meaningful (SURPASS-2 reference) | Greater (5.5 kg more at 15 mg) |
| Cardiovascular risk (established CVD) | Proven MACE reduction (SELECT) | Favorable; CVOT ongoing |
| Pen preference | Dial-a-dose (visible needle option) | Auto-injector (hidden needle) |
| Insurance/cost | Similar list price; check formulary for your plan | |
Medical Disclaimer
This article is for educational purposes only. Ozempic and Mounjaro are prescription medications. The information here does not constitute medical advice and must not replace a conversation with your prescribing clinician. Clinical decisions about which medication is appropriate for you depend on your full medical history, comorbidities, laboratory values, and current medications.
Frequently Asked Questions
Is Mounjaro better than Ozempic?
In the SURPASS-2 head-to-head trial (1,879 T2D patients, 40 weeks), all three Mounjaro doses outperformed Ozempic 1 mg on both HbA1c reduction and weight loss. Mounjaro 15 mg reduced HbA1c by 2.30 percentage points vs 1.86 for Ozempic 1 mg. Whether Mounjaro is better for you depends on your cardiovascular risk, pen preference, and insurance coverage.
Do Mounjaro and Ozempic have the same side effects?
Largely yes. Both cause nausea, diarrhea, constipation, and vomiting, mostly mild to moderate and peaking during dose escalation. In the SURPASS-2 head-to-head trial, nausea rates were comparable at 17-22% for Mounjaro vs approximately 18% for Ozempic. Mounjaro may cause slightly more diarrhea; Ozempic slightly more nausea, but the overall side effect burden is similar.
Can I switch from Ozempic to Mounjaro?
Yes, switching is possible under prescriber guidance. Ozempic and Mounjaro are not dose-equivalent; your prescriber will determine the appropriate Mounjaro starting dose. Most patients restart titration from 2.5 mg to minimize GI side effects. Always discuss the switch timing with your healthcare provider, particularly if you have cardiovascular disease or other comorbidities.
Why did SURPASS-2 compare Mounjaro to Ozempic 1 mg and not 2.4 mg?
SURPASS-2 (2021) used the FDA-approved T2D dose of semaglutide 1 mg, which is the Ozempic indication. The 2.4 mg dose (Wegovy) was not yet widely approved for obesity at the time of the trial. This makes it a T2D-indication-to-T2D-indication comparison, and Mounjaro still outperformed Ozempic at all three tested doses with statistical significance.
Which is better for cardiovascular protection, Ozempic or Mounjaro?
Ozempic (semaglutide) currently has the edge. The SELECT trial (NEJM 2023, more than 17,000 patients) demonstrated a 20% reduction in major cardiovascular events (MACE) in people with obesity and established cardiovascular disease. Mounjaro's cardiovascular outcome data is still emerging from an ongoing trial. For T2D patients with high cardiac risk, this distinction matters clinically.
What is the difference between Ozempic and Wegovy, and between Mounjaro and Zepbound?
Ozempic and Wegovy contain the same molecule (semaglutide) at different doses for different FDA indications: Ozempic (up to 2.0 mg) for type 2 diabetes, Wegovy (2.4 mg) for obesity. Mounjaro (up to 15 mg) and Zepbound (same doses) work the same way: Mounjaro is approved for type 2 diabetes, Zepbound for obesity and weight management. See our detailed Ozempic vs Wegovy comparison for more.
How long does it take Mounjaro and Ozempic to work?
Both medications begin affecting blood sugar within the first week of dosing. Meaningful weight changes typically become noticeable after 4-12 weeks, with maximum benefit at the highest tolerated dose after several months of titration. Mounjaro generally produces greater overall weight loss. Individual response varies considerably based on starting weight, diet, and other factors.
Are Mounjaro and Ozempic available as compounded versions?
Compounded semaglutide and tirzepatide have been available through 503A/503B compounding pharmacies, though the regulatory landscape has been evolving with FDA shortage-list changes. Both brand-name versions have large-trial safety data behind them. Check with your prescriber about current compounded availability and legal status in your region before going that route.
Which drug is newer, Ozempic or Mounjaro?
Ozempic (semaglutide) received FDA approval for type 2 diabetes in 2017. Mounjaro (tirzepatide) received FDA approval for type 2 diabetes in May 2022. Mounjaro is the newer drug. Both have since had their obesity-indication counterparts approved: Wegovy (2021) and Zepbound (2023), respectively.
Can I use the GLP3Planner calculator for both Ozempic and Mounjaro?
Yes. GLP3Planner supports both Ozempic (semaglutide) and Mounjaro (tirzepatide) in its free pharmacokinetic calculator. Use the Mounjaro calculator to visualize tirzepatide drug levels and plan your titration schedule, or the Ozempic calculator for semaglutide. Both are free with no account required and show real-time plasma concentration curves.
Free Calculators for Ozempic and Mounjaro
Visualize drug levels, plan your titration schedule, and track your doses over time. No account needed.
References
- Frias JP, Davies MJ, Rosenstock J, et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2). N Engl J Med. 2021;385(6):503-515. doi: 10.1056/NEJMoa2107519. Primary head-to-head efficacy and safety data used throughout this article.
- Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT). N Engl J Med. 2023;389(24):2221-2232. doi: 10.1056/NEJMoa2307563. 20% MACE reduction with semaglutide in 17,000+ patients.
- FDA. Ozempic (semaglutide) Prescribing Information. FDA. 2017 (updated 2021). Official FDA label for Ozempic including approved T2D dosing.
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med. 2022;387(3):205-216. doi: 10.1056/NEJMoa2206038. 20.9% mean weight loss at 72 weeks with tirzepatide 15 mg.
- Marso SP, Bain SC, Consoli A, et al. Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6). N Engl J Med. 2016;375(19):1834-1844. doi: 10.1056/NEJMoa1607141. 26% MACE relative risk reduction with semaglutide in T2D patients.
- Wilding JPH, Batterham RL, Calanna S, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021;384(11):989-1002. doi: 10.1056/NEJMoa2032183. 14.9% mean weight loss at 68 weeks with semaglutide 2.4 mg.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Ozempic and Mounjaro are prescription medications that require evaluation and prescription by a licensed healthcare provider. Clinical data presented here comes from published peer-reviewed trials; individual patient results will vary. Always consult your prescribing clinician before starting, switching, or stopping any medication. Neither GLP3Planner nor its authors are responsible for clinical decisions made based on this content.
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