Mounjaro vs Ozempic: how they differ.
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Mounjaro and Ozempic are the two GLP-1-type injections Australians search for most. They are often spoken about as if they were the same thing. They are not: they contain different medicines, are approved for different uses and sit differently on the PBS. This page sets out the differences in plain terms, with the trial evidence.
Mounjaro (tirzepatide) acts on two gut-hormone receptors, GIP and GLP-1; Ozempic (semaglutide) acts on GLP-1 only. In Australia, Mounjaro is approved for type 2 diabetes, weight management and sleep apnoea in adults with obesity, but is not on the PBS. Ozempic is approved for type 2 diabetes and is PBS-listed for it; it is not approved for weight management. In head-to-head trials, tirzepatide led to greater weight loss than semaglutide.
- Different medicines: tirzepatide (Mounjaro, by Eli Lilly) versus semaglutide (Ozempic, by Novo Nordisk).
- Mounjaro is approved for weight management in Australia; Ozempic is not, so its use for weight loss is off-label.
- Ozempic is PBS-listed for type 2 diabetes; Mounjaro is not PBS-listed for anything.
- In SURMOUNT-5, tirzepatide averaged 20.2% weight loss versus 13.7% on semaglutide 2.4 mg (the Wegovy dose).
- Both commonly cause nausea, diarrhoea, vomiting and constipation. Which suits you is a decision for your doctor.
- Mounjaro: TGA-registered for type 2 diabetes, weight management and obstructive sleep apnoea in adults with obesity. Not PBS-listed for any use. PBS medicine status.
- Ozempic: TGA-registered for type 2 diabetes, including type 2 diabetes with chronic kidney disease. PBS-listed for type 2 diabetes only (Authority Required). PBS item 15311W.
- Weight management with semaglutide: the registered brand is Wegovy, which is not PBS-listed. Ozempic vs Wegovy.
- Documents checked: Mounjaro CMI (September 2026) and PI (2 October 2026); Ozempic CMI (August 2026) and PI (25 September 2026).
What is the difference between Mounjaro and Ozempic?
The main difference is the medicine inside. Mounjaro contains tirzepatide, which acts on both the GIP and GLP-1 receptors. Ozempic contains semaglutide, which acts on the GLP-1 receptor only. They are also approved for different uses in Australia and are treated differently by the PBS.
| Mounjaro | Ozempic | |
|---|---|---|
| Medicine | Tirzepatide | Semaglutide |
| How it acts | GIP and GLP-1 receptors (dual) | GLP-1 receptor only |
| Approved uses in Australia | Type 2 diabetes; weight management in adults with overweight or obesity; moderate-to-severe sleep apnoea in adults with obesity | Type 2 diabetes; type 2 diabetes with chronic kidney disease |
| Approved for weight management? | Yes | No (weight loss is listed as a side effect) |
| How often | Once a week | Once a week |
| Dose range | 2.5 mg to 15 mg | 0.25 mg to 2 mg |
| Pen | KwikPen: four weekly doses at one strength | Multi-dose pens: 0.25/0.5 mg, 1 mg, 2 mg |
| PBS | Not listed for any use | Listed for type 2 diabetes (Authority Required) |
Sources: Mounjaro CMI, Ozempic CMI, PBS item 15311W, PBS tirzepatide status.
How do Mounjaro and Ozempic work?
Both copy gut hormones your body releases after eating. These hormones prompt insulin release when blood sugar rises, slow how fast the stomach empties and act on appetite centres in the brain. Ozempic copies one hormone, GLP-1. Mounjaro copies two, GLP-1 and GIP.
Neither is insulin, a stimulant or a supplement. More detail: how Mounjaro works.
Is Mounjaro stronger than Ozempic?
In the trials that compared them directly, tirzepatide led to more weight loss than semaglutide. In SURMOUNT-5, adults with obesity lost an average of 20.2% on tirzepatide over 72 weeks compared with 13.7% on semaglutide 2.4 mg, the dose used in Wegovy rather than Ozempic.
| Trial | Who | Comparison | Main result |
|---|---|---|---|
| SURPASS-2 (NEJM 2021) | 1,879 adults with type 2 diabetes on metformin, 40 weeks | Tirzepatide vs semaglutide 1 mg (an Ozempic dose) | Greater HbA1c (blood sugar) reduction with tirzepatide: 2.01 to 2.30 points vs 1.86. Weight loss was also greater. |
| SURMOUNT-5 (NEJM 2025) | 751 adults with obesity, no diabetes, 72 weeks | Tirzepatide vs semaglutide 2.4 mg (the Wegovy dose) | Weight change −20.2% vs −13.7%; waist −18.4 cm vs −13.0 cm. |
Sources: SURPASS-2; SURMOUNT-5. Both trials were open-label (participants knew which medicine they were on) and funded by the maker of tirzepatide.
“Stronger” on average does not mean better for every person. Health history, side effects, cost and which uses each medicine is approved for all matter, and those are for your doctor to weigh.
How much weight do people lose on each?
The numbers come from different trials with different people, so they cannot be compared directly. Mounjaro’s weight-management trial enrolled people with obesity and no diabetes; Ozempic’s trials enrolled people with type 2 diabetes, who tend to lose less weight on any treatment.
| Medicine and trial | Who | Average weight change |
|---|---|---|
| Mounjaro, SURMOUNT-1 (72 weeks) | Adults with obesity or overweight, no diabetes | −15.0% (5 mg), −19.5% (10 mg), −20.9% (15 mg) vs −3.1% placebo |
| Ozempic, SUSTAIN 1 (30 weeks) | Adults with type 2 diabetes | −3.7 kg (0.5 mg), −4.5 kg (1 mg) vs −1.0 kg placebo |
| Ozempic, SUSTAIN FORTE (40 weeks) | Adults with type 2 diabetes | −6.9 kg (2 mg) vs −6.0 kg (1 mg) |
Sources: SURMOUNT-1; Ozempic Australian PI. Mounjaro figures count everyone who started (treatment-regimen analysis).
More on what these numbers mean in practice: Mounjaro results.
Which has more side effects, Mounjaro or Ozempic?
Both have similar side effects, mainly nausea, diarrhoea, vomiting and constipation, which are most common while the dose is being increased. Rates rise with dose for both. Because the figures come from different trials, they show the pattern rather than a fair contest.
| Side effect data | Mounjaro | Ozempic |
|---|---|---|
| Nausea in pooled trials | 12.2% (5 mg), 15.4% (10 mg), 18.3% (15 mg) vs 4.3% placebo | 17.0% (0.5 mg), 19.9% (1 mg) |
| Stopped because of stomach side effects | 3.0% to 6.6% by dose vs 0.4% placebo | 3.9% (0.5 mg), 5.9% (1 mg) |
| Hair loss | Listed in the CMI; 5.1% on 5 mg in SURMOUNT-1 | Listed in the CMI |
Sources: Mounjaro Australian PI; Ozempic Australian PI.
Both CMIs list serious but less common effects, including inflamed pancreas, gallbladder problems, severe allergic reactions and sudden changes in vision. Details: Mounjaro side effects and Ozempic side effects.
Can Ozempic be used for weight loss in Australia?
Ozempic is not approved for weight management in Australia; its approved uses are type 2 diabetes and type 2 diabetes with kidney disease. A doctor prescribing it for weight loss would be prescribing off-label, outside the approved uses, and the PBS subsidy applies only to type 2 diabetes.
Off-label prescribing is not banned, but Ahpra’s September 2026 guidance reminds doctors of their duties when they do it, including informed consent and a sound clinical reason. The TGA’s shortage database showed no active Ozempic shortage on 9 November 2026. Ahpra, 16 September 2026; TGA shortage database.
The semaglutide brand registered for weight management is Wegovy, at higher doses. See Ozempic vs Wegovy and Ozempic in Australia.
Can you switch from Ozempic to Mounjaro?
Switching is a decision for your doctor, who will decide the starting dose and timing. These medicines are not taken together: the Australian documents advise against combining a GLP-1-type medicine with another of the same type.
If you see either medicine sold online without a prescription, or as vials or “compounded” versions, it is not a lawful supply. Read how to spot an illegal seller.
Does what you eat differ between them?
No. The food questions are the same for both: getting enough protein, fibre and fluid from smaller meals, and finding foods that sit well on queasy days. Neither medicine needs a special diet, and food does not change how either works.
Free guides: Mounjaro diet plan, what to eat on Ozempic, protein on a GLP-1 and foods for nausea.
What is the difference between Mounjaro and Ozempic?
Mounjaro contains tirzepatide, which acts on the GIP and GLP-1 receptors. Ozempic contains semaglutide, which acts on GLP-1 only. In Australia Mounjaro is approved for weight management and type 2 diabetes but is not on the PBS; Ozempic is approved for type 2 diabetes and is PBS-listed for it.
Is Mounjaro stronger than Ozempic?
In head-to-head trials tirzepatide led to more weight loss. In SURMOUNT-5, people lost an average of 20.2% on tirzepatide compared with 13.7% on semaglutide 2.4 mg, the Wegovy dose, over 72 weeks.
Is Ozempic approved for weight loss in Australia?
No. Ozempic is approved for type 2 diabetes. Use for weight loss is off-label. The semaglutide brand registered for weight management is Wegovy.
Is Mounjaro or Ozempic on the PBS?
Ozempic is PBS-listed for type 2 diabetes. Mounjaro is not PBS-listed for any use; Eli Lilly declined the type 2 diabetes listing recommended in March 2026.
Which has fewer side effects, Mounjaro or Ozempic?
Both commonly cause nausea, diarrhoea, vomiting and constipation, mostly while the dose is being increased. The available figures come from different trials, so they cannot settle which is easier to take.
Can you take Mounjaro and Ozempic together?
No. They are not used together. Switching from one to the other is a decision for your doctor.
Related explainers: Mounjaro in Australia · Ozempic in Australia · Mounjaro vs Wegovy · Ozempic vs Wegovy · Mounjaro results
Primary sources checked for this page.
- Mounjaro KwikPen Consumer Medicine Information (Australia), prepared September 2026.
- Mounjaro Australian Product Information, revised 2 October 2026.
- Ozempic Consumer Medicine Information (Australia), prepared August 2026.
- Ozempic Australian Product Information, revised 25 September 2026.
- Frías et al., SURPASS-2, New England Journal of Medicine, 2021.
- Jastreboff et al., SURMOUNT-1, New England Journal of Medicine, June 2022.
- Aronne et al., SURMOUNT-5, New England Journal of Medicine, 2025.
- PBS item 15311W: semaglutide (Ozempic), retrieved 9 November 2026.
- PBS medicine status: tirzepatide, information current at 1 November 2026.
- Ahpra: crackdown on reckless prescribing as regulator ramps up peptides oversight, 16 September 2026.
- TGA Medicine Shortage Reports Database: semaglutide, retrieved 9 November 2026.
Editorial method: Australian regulatory documents (the TGA-approved Product Information and Consumer Medicine Information, the TGA and the PBS) were checked first, then peer-reviewed trial publications. Trial numbers are group averages and say which analysis they come from. Status statements are dated and may change. A named clinical review is pending; until then this is editorial research, not clinical opinion. See the Preptide editorial policy.
Important: General information only, not medical advice. Brand names are registered trademarks of their respective owners; Preptide is independent and is not affiliated with, endorsed by or sponsored by any medicine manufacturer. Preptide is food, not medication, and does not prescribe, sell, recommend or promote prescription medicines. Talk to your doctor or pharmacist about any medicine. In an emergency call 000. Read our editorial policy and Health Acknowledgement.