Ozempic, Wegovy and Mounjaro: Which GLP-1 Medication Is Best for Weight Loss in Australia?
Ozempic, Wegovy and Mounjaro: Which GLP-1 Medication Is Best for Weight Loss in Australia?
GLP-1 receptor agonists have transformed non-surgical weight management. Ozempic, Wegovy and Mounjaro are now prescribed widely in Australia — and with good reason. These medications produce significantly greater weight loss than any previous drug therapy. But they work differently, have different approved indications, and suit different patients.
This guide breaks down each medication plainly, so you can have an informed conversation with your doctor about what may be right for you.
What Are GLP-1 Medications and How Do They Work?
GLP-1 (glucagon-like peptide-1) is a hormone naturally released by your gut after eating. It signals the brain to feel full, slows the rate at which your stomach empties, reduces appetite, and — in people with type 2 diabetes — helps regulate blood sugar.
GLP-1 medications mimic or enhance these effects, producing prolonged appetite suppression and reduced caloric intake. Explore our full guide to GLP-1 medications.
Ozempic (Semaglutide) — Weekly Injection for Diabetes, Used Off-Label for Weight
Active ingredient: Semaglutide
Approved use in Australia: Type 2 diabetes management
Dosing: Once weekly subcutaneous injection
Weight loss above placebo: 8–10kg
Ozempic is TGA-approved in Australia for blood sugar control in adults with type 2 diabetes. At higher doses, it also produces significant weight loss and is widely prescribed off-label for obesity management.
It works as a GLP-1 receptor agonist — increasing feelings of satiety, reducing appetite, and delaying gastric emptying. Common side effects include nausea, reflux, bloating and constipation, which typically improve as doses are titrated gradually upward.
Wegovy (High-Dose Semaglutide) — Approved for Chronic Weight Management
Active ingredient: Semaglutide (higher dose than Ozempic)
Approved use in Australia: Chronic weight management in adults with obesity or overweight with weight-related conditions
Dosing: Once weekly subcutaneous injection
Weight loss above placebo: 8–12% of body weight over 1–1.5 years
Wegovy uses the same active ingredient as Ozempic (semaglutide) but at a higher dose specifically approved for weight management. In clinical trials, patients lost an average of 8–12% of their total body weight over 1–1.5 years when combined with lifestyle changes.
It works through the same GLP-1 pathway — reducing appetite and slowing gastric emptying. Side effects mirror Ozempic: nausea, reflux, bloating and constipation are most common, particularly during dose escalation phases.
Mounjaro (Tirzepatide) — Dual-Action for Maximum Results
Active ingredient: Tirzepatide
Approved use in Australia: Type 2 diabetes; weight management approval in progress
Dosing: Once weekly subcutaneous injection
Weight loss above placebo: 10–12kg; clinical trials show 12–18% total body weight loss
Mounjaro is the newest and most powerful of these three medications. Unlike semaglutide, which targets only the GLP-1 pathway, tirzepatide targets both GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptors. This dual action produces stronger appetite suppression and significantly better weight loss outcomes.
In clinical trials, patients lost an average of 12–18% of their total body weight over 1–1.5 years — making Mounjaro the most effective weight loss medication currently available. Side effects are similar to Wegovy and include nausea, reflux, bloating, diarrhoea or constipation, particularly during dose increases.
Head-to-Head Comparison
| Feature | Ozempic | Wegovy | Mounjaro |
|---|---|---|---|
| Active ingredient | Semaglutide | Semaglutide (higher dose) | Tirzepatide |
| Mechanism | GLP-1 agonist | GLP-1 agonist | GLP-1 + GIP dual agonist |
| Dosing | Weekly injection | Weekly injection | Weekly injection |
| Average weight loss | 8–10kg | 8–12% body weight | 12–18% body weight |
| TGA weight loss approval | No (off-label) | Yes | Pending |
| Best for | Type 2 diabetes + weight loss | Primary weight management | Maximum non-surgical weight loss |
How Do GLP-1 Medications Compare to Surgery?
Even the best GLP-1 medications produce weight loss roughly 5 times less than bariatric surgery on average. Surgery produces 30–50% total body weight loss versus 8–18% with medication. Surgery also produces more durable remission of conditions like type 2 diabetes and sleep apnoea.
That said, GLP-1 medications are appropriate for many patients — particularly those not yet eligible for surgery, those with BMI in the 30–40 range, or those who prefer a non-surgical path. Read our comparison of weight loss surgery vs Ozempic for heart health.
They’re also used post-bariatric surgery to manage weight regain, alongside dietary intervention and behavioural support.
Important Considerations
- Weight returns when medication stops. Unlike surgery, GLP-1 medications must be continued indefinitely to maintain results. Most patients regain weight after stopping. This is an important cost and lifestyle consideration.
- They don’t work alone. Best results combine medication with dietary changes, regular exercise and behavioural support.
- Not suitable for everyone. People with a personal or family history of medullary thyroid carcinoma or MEN2 syndrome should not use GLP-1 medications. Always consult your GP or specialist.
Understand why weight comes back and how to support lasting results through a combination approach. Compare all weight loss options or speak with Dr. Maani’s team about what’s right for you.
Frequently Asked Questions
Is Mounjaro better than Ozempic for weight loss?
In clinical trials, Mounjaro (tirzepatide) produces significantly greater weight loss than Ozempic (semaglutide) — averaging 12–18% total body weight versus 8–10kg. This is because Mounjaro targets both GLP-1 and GIP hormone pathways, while Ozempic targets GLP-1 alone.
Is Ozempic approved for weight loss in Australia?
Ozempic is TGA-approved in Australia for type 2 diabetes management. It’s commonly prescribed off-label for weight loss. Wegovy — the same active ingredient at a higher dose — is approved specifically for chronic weight management.
How much weight can you lose on Wegovy in Australia?
Clinical trials show an average of 8–12% total body weight loss over 1–1.5 years on Wegovy, combined with lifestyle changes. Individual results vary based on starting weight, diet, and exercise habits.
Do you regain weight after stopping Ozempic or Mounjaro?
Yes. Most patients regain a significant portion of the weight lost after stopping GLP-1 medications. This is a key difference from bariatric surgery, which produces structural changes that continue to assist weight management long-term.