Mounjaro vs Ozempic- Key Differences & Outcomes

Is the war on diabetes and obesity over? The treatment landscape for type 2 diabetes and obesity has changed drastically in the past few years. Two of the most sought-after injectable treatments today are Tirzepatide (Mounjaro & Zepbound)  and Semaglutide (Ozempic & Wegovy). Both treatments are safe, effective and clinically proven- but they work slightly differently. Naturally, many patients will wonder, “Which treatment is right for me? Ozempic or Mounjaro?”, and this is where understanding the key differences and benefits of these treatment options helps patients make an informed decision together with their healthcare provider.

In this article, we’ll break down the differences between Mounjaro and Ozempic, including how they work, what they treat, their effectiveness, side effects, availability and cost.

Caption: Mounjaro vs Ozempic – key differences

Caption: Mounjaro and Ozempic both activate the GLP-1 pathway, while only Mounjaro activates the GIP pathway.

Semaglutide (Ozempic)

Ozempic targets only GLP-1 receptors, which:

• Stimulate insulin release and lower blood sugar levels
• Slow digestion and gastric emptying
• Promote moderate weight loss (10-15% of body weight)

Mounjaro (Tirzepatide)

Mounjaro is a dual pathway medication, acting by mimicking the function of two hormones:

• GIP (glucose-dependent insulinotropic polypeptide)
• GLP-1 (glucagon-like peptide-1)

This dual action helps:

• Increase Insulin secretion and reduce blood sugar levels
• Reduce appetite and food cravings
• Delay gastric emptying
• Promote significant weight loss (20-25% of body weight)

Caption: Tirzepatide (Mounjaro) is a dual-action medication working through GLP-1 and GIP pathways

Mounjaro vs Ozempic- clinical studies

SURPASS-2 Trial: Tirzepatide (Mounjaro) versus Semaglutide (Ozempic) for diabetes

In clinical trials, Tirzepatide (Mounjaro) gave improved results compared to Semaglutide (Ozempic) for diabetes control and weight loss. The SURPASS-2 trial treated patients with type 2 diabetes with Tirzepatide (Mounjaro) and Semaglutide (Ozempic). The results of this landmark clinical trial were published in the New England Journal of Medicine 2021. In this 40-week study, 1879 patients were randomly assigned, in a 1:1:1:1 ratio, to receive tirzepatide at a dose of 5 mg, 10 mg, or 15 mg or semaglutide at a dose of 1 mg per week. At baseline, the mean Hba1c level was 8.28%, the mean age 56.6 years, and the mean weight 93.7 kg. The primary end point was the change in the Hba1c level. Tirzepatide at all doses was more effective than semaglutide, with greater reduction in Hba1c (ie better diabetic control) and weight. The side effect profile of both medications was similar.

Caption: SURPASS 2 trial- Semaglutide versus tirzepatide for diabetes (Hba1c and fasting glucose levels)

For diabetes treatment

Both Semaglutide (Ozempic) and Tirzepatide (Mounjaro) are effective treatments for diabetes, helping to lower Hba1c and fasting blood glucose levels effectively. In the SURPASS 2 trial,  Tirzepatide, aka Mounjaro, at all doses (5mg, 10mg and 15mg) was more effective at lowering Hba1c and blood glucose levels compared to Semaglutide 1mg, aka Ozempic.

• Mounjaro: Hba1c reductions up to 2.0–2.4%
• Ozempic: Hba1c reductions up to 1.5–1.8%

Caption: SURPASS 2 trial Tirzepatide versus Semaglutide for weight loss in diabetic patients (weight loss in kg and by percentage of body weight), lipid levels

For Weight Loss

Tirzepatide is licensed for weight loss and treatment of obesity under the brand name Zepbound, while Semaglutide is licensed under the brand name Wegovy. In the SURPASS 2 trial, Tirzepatide at all doses (5mg, 10mg and 15mg) was found to result in greater weight loss than semaglutide 1mg.

Both Tirzepatide and Semaglutide treatment can lead to significant weight loss.

• Tirzepatide: Average loss of 20-25% of body weight (at 15 mg)
• Semaglutide: Average loss of 10–15% of body weight (at 2 mg)

Conclusion

Both Tirzepatide (Mounjaro) and Semaglutide (Ozempic) are once-weekly injections for the treatment of diabetes and obesity. Due to the dual pathway mechanism of Tirzepatide (Mounjaro), this medication has greater effects on blood sugar levels and weight loss than Semaglutide (Ozempic). However, due to global supply shortages, Tirzepatide (Mounjaro) is not yet available in Singapore and is expected to become available in 2026-2027. Patients who have been started on Tirzepatide (Mounjaro) by their doctors overseas are able to bring in the medications for personal usage, and may also approach selected medical clinics to obtain the supply of Tirzepatide (Mounjaro).

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