Ozempic vs Mounjaro vs Wegovy: Which GLP-1 is Best for Weight Loss in Australia?

By Dr. Jason Maani | Medically reviewed July 2026

GLP-1 receptor agonists have transformed weight management in Australia. But with Ozempic, Wegovy and Mounjaro all available — and more on the way — choosing the right one is genuinely confusing.

This guide cuts through the marketing and gives you a science-based comparison: how each drug works, what results to expect, what they cost in Australia, and which is most appropriate for different situations.

What Is a GLP-1 Medication?

GLP-1 (glucagon-like peptide-1) is a hormone produced in your gut after eating. It signals your brain to reduce appetite, slows stomach emptying, and regulates insulin. GLP-1 receptor agonists are synthetic versions of this hormone — they mimic its effects continuously, helping you feel full sooner and eat less overall.

All three medications discussed here (Ozempic, Wegovy, Mounjaro) work via this pathway, but they differ in their molecular targets, dosing, and clinical outcomes.

Ozempic (Semaglutide 0.25–2mg weekly)

What it is: Ozempic contains semaglutide, a GLP-1 receptor agonist developed by Novo Nordisk. It is TGA-approved in Australia primarily for Type 2 diabetes but widely prescribed off-label for weight management.

How it works: Weekly subcutaneous injection. Doses are escalated from 0.25mg to a maximum of 2mg over several months to reduce side effects.

Weight loss results: Clinical trials show average weight loss of 12–15% of body weight over 68 weeks. Real-world results in Australia typically range from 8–12% depending on lifestyle adherence.

Cost in Australia:

• With PBS listing for Type 2 diabetes: approximately $32–$44/month (general) or $6.60/month (concession)
• Off-label/private prescription: $200–$350/month
• Currently subject to supply shortages in Australia (as of 2026)

Best suited for: People with Type 2 diabetes and overweight/obesity who need dual metabolic and weight management benefits.

Limitations: Not TGA-approved for weight loss specifically. Supply constraints remain an issue. Does not target GIP receptors (see Mounjaro).

Wegovy (Semaglutide 2.4mg weekly)

What it is: Wegovy is the same active ingredient as Ozempic (semaglutide) but at a higher dose (2.4mg vs 2mg max) and specifically TGA-approved for chronic weight management in adults with obesity or overweight with weight-related comorbidities.

How it works: Weekly injection, dose escalation over 16–20 weeks to 2.4mg. The higher dose produces stronger appetite suppression than Ozempic.

Weight loss results: The STEP trial program showed average weight loss of ~15–17% of body weight over 68 weeks — the highest among the semaglutide preparations. Some participants achieved 20%+ loss.

Cost in Australia:

• Currently not PBS-listed for weight management
• Private cost: approximately $350–$500/month
• Some private health insurers may partially cover with documented obesity diagnosis

Best suited for: Adults with BMI ≥30, or BMI ≥27 with weight-related conditions (sleep apnoea, high blood pressure, high cholesterol), who want the highest-evidence semaglutide option specifically approved for weight loss.

Limitations: Significant cost without PBS support. Side effects (nausea, vomiting, constipation) are more pronounced at 2.4mg dose.

Mounjaro (Tirzepatide 2.5–15mg weekly)

What it is: Mounjaro contains tirzepatide, developed by Eli Lilly. It is unique because it is a dual GIP/GLP-1 receptor agonist — it activates both the glucose-dependent insulinotropic polypeptide (GIP) receptor and the GLP-1 receptor simultaneously.

How it works: Weekly injection, escalated from 2.5mg to a maximum of 15mg over approximately 20 weeks. The dual mechanism produces stronger metabolic effects than GLP-1 alone.

Weight loss results: The SURMOUNT trial program showed average weight loss of ~20–22% of body weight — the highest of any currently available injectable weight loss medication. Some participants lost over 25% of body weight.

Cost in Australia:

• TGA-approved (2024) but not currently PBS-listed for weight management
• Private cost: approximately $350–$600/month depending on dose
• Gaining traction rapidly; PBS listing discussions ongoing as of 2026

Best suited for: Adults seeking the highest achievable weight loss from injectable medication, particularly those who have not achieved satisfactory results with semaglutide-based treatments, or those with Type 2 diabetes where dual metabolic benefits are important.

Limitations: Highest cost. Relatively newer — long-term safety data still accumulating beyond 3 years.

Head-to-Head Comparison

Side Effects: What to Expect

All three medications share a common side effect profile due to their GLP-1 mechanism:

• Nausea (most common, especially during dose escalation — usually improves after 4–6 weeks)
• Vomiting (less common; triggered by eating too quickly or large portions)
• Constipation or diarrhoea
• Fatigue during escalation
• Injection site reactions (mild, temporary)

Rare but serious: pancreatitis, gallbladder disease, thyroid concerns (based on animal studies; human risk unclear). Discuss your full medical history with your prescribing doctor.

Mounjaro tends to have a slightly different nausea profile due to GIP action — some patients find it better tolerated than semaglutide at equivalent weight loss results.

Who Should Be Prescribed Which Medication?

Start with Ozempic if:

• You have Type 2 diabetes and can access PBS pricing
• Budget is a primary constraint
• You want an established, well-studied option

Choose Wegovy if:

• You do not have diabetes but need the highest-evidence semaglutide option
• You want a medication specifically TGA-approved for weight management
• You can afford private costs or have insurance coverage

Choose Mounjaro if:

• You want maximum possible weight loss from injectable medication
• You have already tried semaglutide without adequate results
• You have Type 2 diabetes and want the strongest dual metabolic benefit
• Budget is flexible

Consider bariatric surgery instead if:

• Your BMI is above 40, or above 35 with serious comorbidities
• You’ve tried GLP-1 medications without achieving your target
• You want a permanent structural solution rather than ongoing medication

For more information on how GLP-1 medications compare to surgical options, read our guide: GLP-1 vs Bariatric Surgery: Which is Right for You?

Important: You Can’t Get These Without a Prescription

All three medications require a prescription from a registered medical practitioner in Australia. They are not available over the counter. Prescribing should follow a clinical assessment including BMI, metabolic history, and comorbidities.

Be wary of online providers that offer these medications without thorough clinical assessment. The 99 Percent connects Australians with science-backed information to help make informed decisions with their doctor.

Frequently Asked Questions

Q: Can I switch between Ozempic, Wegovy and Mounjaro? A: Yes, switching is possible and sometimes clinically appropriate — for example, moving from Ozempic to Mounjaro if results plateau. Always do this under medical supervision with appropriate washout or tapering periods.

Q: How long do you need to take GLP-1 medications for weight loss? A: Clinical evidence shows weight regain occurs when these medications are stopped. Most evidence suggests ongoing use is needed to maintain results, similar to blood pressure or cholesterol medication. This is one reason some patients and doctors prefer bariatric surgery as a one-time structural intervention.

Q: Is Ozempic or Mounjaro better for weight loss in Australia? A: The clinical data clearly shows Mounjaro (tirzepatide) produces greater average weight loss (20–22%) than Ozempic (12–15%). However, individual responses vary, PBS access for Ozempic in diabetes significantly reduces cost, and not everyone needs maximum weight loss. The “best” medication depends on your individual circumstances, budget and medical history.

Q: Are GLP-1 medications covered by Medicare in Australia? A: Ozempic is PBS-listed for Type 2 diabetes. Wegovy and Mounjaro are not currently PBS-listed for weight management in Australia as of July 2026, meaning they require private prescription at full cost.

Q: What happens if I stop taking GLP-1 medication? A: Most people regain a significant portion of lost weight within 12 months of stopping. The STEP 4 trial found participants regained approximately two-thirds of lost weight within a year of discontinuing Wegovy. This is a biological response, not a failure of willpower.

Q: Is Mounjaro available in Australia? A: Yes. Mounjaro (tirzepatide) received TGA approval in Australia in 2024 and is available via private prescription from doctors who have undergone relevant training. It is not currently PBS-listed for weight management.

The Bottom Line

For most Australians weighing up GLP-1 options:

• Mounjaro produces the most weight loss — roughly 20–22% on average
• Wegovy is the most specifically approved for weight management and produces strong results at 15–17%
• Ozempic is the most accessible for people with diabetes due to PBS coverage
• All require ongoing use to maintain results

The right choice depends on your medical history, budget, access, and treatment goals. Work with a doctor experienced in weight management — not just a telehealth prescriber — to get the most from whichever option you choose.

Explore our full guide to GLP-1 medications or learn about surgical weight loss options if medication alone isn’t achieving your goals.

Dr. Jason Maani is the founder of The 99 Percent and specialises in evidence-based weight management education for Australians. This article is for information purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.