Wegovy vs Mounjaro Australia: Which Weight Loss Injection Is Right for You?
Key Takeaways
Wegovy and Mounjaro are the two most effective weight loss medications in Australia. Here's how they compare on efficacy, cost, side effects and access.
Two Medications, One Question Everyone Is Asking
Wegovy and Mounjaro are the two most effective weight loss medications available in Australia right now. Both are TGA-approved for chronic weight management in adults. Both are weekly injections. Both are private prescription medications not yet subsidised by the PBS for weight management. And both consistently outperform everything that came before them in terms of average weight loss achieved in clinical trials.
So which one is right for you? This guide covers the clinical differences, the trial data side by side, the practical cost and access differences, and the situations where one might be preferred over the other.
The Fundamental Difference: One Hormone vs Two
Wegovy (semaglutide 2.4mg) is a GLP-1 receptor agonist. It mimics glucagon-like peptide-1, a gut hormone that reduces appetite, slows gastric emptying, and improves insulin sensitivity. It activates one receptor type.
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist. It activates both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor simultaneously. GIP receptors are found in fat tissue, muscle, brain, and pancreas. The additional GIP activation appears to produce greater appetite suppression and more significant changes in fat metabolism than GLP-1 agonism alone.
This mechanistic difference is the primary reason Mounjaro produces greater average weight loss than Wegovy in clinical trials.
The Trial Data: Side by Side
The most relevant comparison comes from the STEP (semaglutide) and SURMOUNT (tirzepatide) trial programs:
- Wegovy (semaglutide 2.4mg) — STEP 1: Mean weight loss of ~15–17% of body weight over 68 weeks
- Mounjaro (tirzepatide 10mg) — SURMOUNT-1: Mean weight loss of ~19.5% of body weight over 72 weeks
- Mounjaro (tirzepatide 15mg) — SURMOUNT-1: Mean weight loss of ~20.9% of body weight over 72 weeks
A direct head-to-head trial (SURMOUNT-5) comparing tirzepatide to semaglutide 2.4mg confirmed tirzepatide's superiority: participants on tirzepatide lost approximately 47% more weight than those on semaglutide.
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Our GPs can assess your suitability for tirzepatide via bulk billed telehealth. No referral, no waiting room.
These are averages across large populations. Individual responses vary — some patients do exceptionally well on semaglutide; others find tirzepatide produces significantly better results for them personally.
Side Effects: How Do They Compare?
The side effect profiles of Wegovy and Mounjaro are broadly similar, as both act on GLP-1 receptors:
- Gastrointestinal effects (nausea, vomiting, diarrhoea, constipation): Common to both; worst during dose escalation
- Injection site reactions: Mild and similar for both
- Rare serious effects: Pancreatitis risk applies to both; thyroid C-cell tumour risk in those with relevant personal/family history
Mounjaro uses a slower escalation schedule (starting at 2.5mg, increasing every 4 weeks) compared to Wegovy (starting at 0.25mg, increasing every 4 weeks). Some patients report Mounjaro is better tolerated during the early titration phase due to the very low starting dose.
Cost Comparison in Australia (2026)
Both are private prescription medications for weight management — neither is PBS-subsidised for this purpose. Approximate monthly costs at pharmacy:
- Wegovy (titration doses): ~$160–$220/month
- Wegovy (maintenance 2.4mg): ~$200–$250/month
- Mounjaro (2.5mg–5mg starting doses): ~$180–$270/month
- Mounjaro (10mg–15mg maintenance): ~$280–$350/month
Mounjaro at maintenance doses is meaningfully more expensive than Wegovy. For some patients, this is a decisive factor.
Which Should You Choose?
There is no universal answer, but here is a practical framework:
Wegovy may be preferable if:
- Cost is a significant consideration
- You have previously tolerated semaglutide well (e.g., on Ozempic)
- Your GP recommends it based on your clinical history
Mounjaro may be preferable if:
- Maximum weight loss efficacy is the priority
- You have type 2 diabetes (tirzepatide has a particularly strong evidence base for metabolic improvement)
- You tried semaglutide and found the results insufficient
- Your GP assesses it as the better clinical fit for your situation
The right answer is ultimately between you and your GP. Weight Loss GP Australia offers bulk billed telehealth consultations where our GPs can help you assess which medication suits your clinical situation and goals.
Wondering if Mounjaro is right for you?
Request an appointment and our GPs will assess your suitability for tirzepatide — bulk billed through Medicare. No referral required.
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