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Key takeaways
Ozempic and Mounjaro are brand-name prescription medications for blood sugar management in people with Type 2 diabetes.
Both Ozempic and Mounjaro cause gastrointestinal side effects, but Ozempic typically causes them more frequently.
Compared to Ozempic, Mounjaro tends to have a slightly lower risk of side effects and tends to be more effective for weight management and blood sugar management.
Drug side effects and benefits can vary from person to person, so consult a healthcare professional about whether Ozempic or Mounjaro is right for you.
Celebrities and social media have created significant buzz around injectable medications like Ozempic (semaglutide) and Mounjaro (tirzepatide). These two brand-name drugs are sometimes prescribed off-label for weight loss, but they’re not approved for that purpose. Mounjaro and Ozempic are both approved by the Food and Drug Administration (FDA) for the treatment of Type 2 diabetes. Ozempic has two additional FDA-approved uses as well. If you’re considering Ozempic or Mounjaro, you may wonder which is better for you, especially if the drugs’ potential side effects are a factor.
What’s the difference between Ozempic and Mounjaro?
The main difference between Ozempic and Mounjaro is their active ingredient and how they work. Ozempic contains semaglutide, whereas Mounjaro contains tirzepatide.
Because of their different ingredients, Ozempic and Mounjaro belong to overlapping but not identical drug classes. Semaglutide and tirzepatide are classified as glucagon-like peptide-1 receptor agonists, or GLP-1 agonists, but since tirzepatide also targets a second receptor, it is classified as a dual GIP/GLP-1 receptor agonist. Activating these receptors is what helps Ozempic and Mounjaro regulate blood sugar levels and reduce appetite.
Ozempic and Mounjaro are both FDA-approved for blood sugar control in the treatment of Type 2 diabetes. Ozempic is also approved to reduce the risk of major adverse cardiovascular events in adults with both Type 2 diabetes and heart disease, and to prevent the worsening of kidney disease and cardiovascular death in adults with Type 2 diabetes and chronic kidney disease (CKD). As of now, Mounjaro has not been approved for those uses.
Finally, Ozempic and Mounjaro have different dosages. Ozempic dosage starts at 0.25 mg injected once weekly and can be increased to a maximum of 2 mg once weekly. Mounjaro’s starting dose is 2.5 mg, injected once weekly. The maximum Mounjaro dose is 15 mg once weekly. But that doesn’t mean Mounjaro is 10 times stronger than Ozempic—their active ingredients work differently and require different dosages to achieve their effects. Your healthcare provider will prescribe a dosing schedule that aligns with your treatment plan.
An important note: Ozempic and Mounjaro are not FDA approved for weight loss. The brand-name weight loss drugs Wegovy (semaglutide) and Zepbound (tirzepatide) contain the same active ingredients as Ozempic and Mounjaro, respectively, and are FDA approved for weight loss.
What are the common side effects of Ozempic?
Common Ozempic side effects include gastrointestinal issues such as nausea and diarrhea. In clinical trials, nausea was the most common side effect, with 16% of participants affected, based on the 0.5 mg dose (percentages vary slightly, depending on the dose). The next most commonly reported side effects were diarrhea (9%) and stomach pain (7%), followed by vomiting and constipation (both 5%). Some Ozempic users also report muscle pain, fatigue, and eye issues.
RELATED: Can Ozempic cause heart palpitations?
What are the common side effects of Mounjaro?
Most Mounjaro side effects are also gastrointestinal. In clinical trials, nausea and diarrhea were the most commonly reported side effects, affecting 12% of Mounjaro users (based on the 5 mg dose; other doses may vary in the percentage affected). Other common side effects included indigestion (8%), constipation (6%), and stomach pain (6%).
Serious side effects of Ozempic and Mounjaro
Both drugs may be associated with serious side effects in rare cases. If you have symptoms of an allergic reaction, such as trouble breathing, hives, or swelling, get emergency medical help. You should also get urgent medical help for acute symptoms like severely low blood sugar, vision changes, a lump in the neck, or any other concerning symptoms. This is not a full list of serious side effects, and others may occur. Consult your healthcare provider for more information about possible side effects.
Compare Ozempic vs. Mounjaro side effects |
||||
|---|---|---|---|---|
| Ozempic (0.5 mg dose) | Mounjaro (5 mg dose) | |||
| Side effect | Applicable? | Frequency | Applicable? | Frequency |
| Nausea | Yes | 16% | Yes | 12% |
| Vomiting | Yes | 5% | Yes | 5% |
| Constipation | Yes | 5% | Yes | 6% |
| Diarrhea | Yes | 9% | Yes | 12% |
| Indigestion | Yes | 3.5% | Yes | 8% |
| Stomach pain | Yes | 7% | Yes | 6% |
Frequency is not based on data from a head-to-head trial and may vary by dose. This may not be a complete list of adverse effects that can occur. Please refer to your healthcare provider to learn more.
Source: DailyMed (Mounjaro), DailyMed (Ozempic)
Is Mounjaro better than Ozempic?
From a side-effect point of view, Mounjaro may be better than Ozempic. It may also be better for weight loss (an off-label use).
“Patients do report fewer side effects with tirzepatide, though this is variable, and I have had patients with no side effects on both medications,” says Mir Ali, MD, board-certified general surgeon, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, California.
In clinical trials, every side effect except constipation had a higher incidence rate in Ozempic than in Mounjaro. Six percent of Mounjaro clinical trial participants reported constipation, whereas only 5% of Ozempic clinical trial participants experienced constipation.
As for effectiveness, Michelle Lin, DO, family medicine provider and owner of My Family Doc in Las Vegas, Nevada, points to data suggesting that Mounjaro gets slightly better results than Ozempic:
- Weight loss: In a 2024 study of 18,386 adults with overweight or obesity, tirzepatide users reduced their body weight by 15.3%, and semaglutide users reduced theirs by 8.3% after 12 months. “Overall, Mounjaro has been shown to have higher rates of weight loss than Ozempic,” concludes Dr. Lin. Another 2025 study found that people taking tirzepatide lost close to 50% more weight than people taking semaglutide.
- Blood sugar management. Research also suggests that tirzepatide lowers average blood glucose levels more significantly than semaglutide.
Ultimately, only a healthcare provider familiar with your medical history, health condition(s), side effect concerns, and other medications you’re taking can decide whether Ozempic or Mounjaro is the best drug for you.
- Ozempic – semaglutide injection, solution, DailyMed (2025)
- Mounjaro – tirzepatide injection, solution, DailyMed (2025)
- Semaglutide vs tirzepatide for weight loss in adults with overweight or obesity, JAMA Network (2024)
- Tirzepatide versus semaglutide once weekly in patients with Type 2 diabetes, The New England Journal of Medicine (2021)
- Tirzepatide as compared with semaglutide for the treatment of obesity, The New England Journal of Medicine (2025)