Weight Loss Injections Australia — Ozempic vs Mounjaro vs Wegovy Compared

Ozempic and Wegovy contain the same active molecule — semaglutide — at different doses. Mounjaro contains tirzepatide, a different compound with a dual receptor mechanism. This distinction matters for both weight loss magnitude and liver disease treatment pathways.

Ozempic (semaglutide 1mg) activates GLP-1 receptors in the brain and gut, reducing appetite and slowing gastric emptying. It was developed and TGA-approved for type 2 diabetes. Many Australians use it off-label for weight management, though Wegovy is the TGA-approved weight loss dose of semaglutide.

Mounjaro (tirzepatide) activates both GLP-1 and GIP receptors simultaneously. The additional GIP pathway contributes to its superior average weight loss in head-to-head trials. TGA-approved for weight management in Australia since September 2024.

Wegovy (semaglutide 2.4mg) is the higher-dose semaglutide formulation specifically approved for weight management and — since April 2026 — for MASH with moderate to advanced fibrosis (F2–F3). The ESSENCE trial data underpinning the MASH indication used this 2.4mg dose.

The SURMOUNT-5 trial directly compared tirzepatide and semaglutide, finding approximately 20% body weight reduction with Mounjaro versus approximately 14% with semaglutide at 72 weeks. Wegovy's weight loss results in its own trials fall in the 14–17% range.

For maximum weight reduction, Mounjaro currently leads on average trial data. However, individual response varies — some patients achieve excellent results on semaglutide and do not tolerate tirzepatide, and vice versa. Dose titration speed, adherence, concurrent diet, and baseline metabolic status all influence outcomes.

Weight loss of 7–10% produces clinically meaningful liver fat reduction in MASLD. Weight loss of 10% or more is associated with MASH resolution in many patients. All three medications can achieve these thresholds — Mounjaro reaches them faster on average.

Ozempic vs Mounjaro — detailed comparison →

Mounjaro vs Wegovy — detailed comparison →

Type 2 diabetes: Ozempic is PBS-subsidised at $31.60 per prescription for T2D, making it the most accessible option. Mounjaro is also TGA-approved for T2D but is not PBS-listed. Both produce liver benefit through weight loss and glycaemic improvement.

Weight management without diabetes: Mounjaro or Wegovy are the TGA-approved choices. Mounjaro produces greater average weight loss; Wegovy has a narrower PBS pathway for patients with established cardiovascular disease meeting BMI criteria.

Confirmed MASH with F2–F3 fibrosis: Wegovy is the only TGA-approved treatment for this indication as of April 2026. This is not a comparison question — it is a regulatory and evidence-based decision. Referral to a hepatologist or gastroenterologist is appropriate.

MASLD without confirmed MASH: Any of the three medications provides meaningful benefit through weight loss. Choice depends on cost, tolerance, and whether you have type 2 diabetes qualifying for PBS Ozempic.

All three GLP-1 medications improve liver health, primarily through weight loss, improved insulin sensitivity, and direct hepatic effects of GLP-1 receptor activation. The magnitude of liver benefit correlates with weight loss achieved.

Semaglutide (Ozempic/Wegovy): The most mature liver evidence base. ESSENCE trial: 62.9% MASH resolution at 72 weeks with Wegovy 2.4mg. TGA provisional approval for MASH in April 2026.

Tirzepatide (Mounjaro): Phase 2 liver data shows significant liver fat and enzyme improvement. SYNERGY-NASH phase 3 results expected 2026. Greater average weight loss suggests greater liver fat reduction.

Approximately 30% of Australian adults have MASLD, and many do not know it. Starting a weight loss injection without baseline liver assessment means undiagnosed fibrosis may go unmonitored during treatment.

Ozempic and fatty liver →

Wegovy and fatty liver →

Mounjaro and liver disease →

Weight loss injections and liver health →

All GLP-1 receptor agonists — Ozempic, Wegovy, and Mounjaro — carry an increased risk of gallstones and gallbladder-related events. Meta-analysis data suggests approximately 27% higher gallstone risk compared to non-GLP-1 users.

Rapid weight loss itself increases gallstone formation regardless of medication class. The combination of GLP-1-mediated gallbladder hypomotility and significant weight reduction creates a dual risk pathway.

Symptoms to watch for include right upper abdominal pain (especially after fatty meals), nausea, vomiting, and fever. Gallstone pancreatitis is a medical emergency requiring immediate hospital assessment.

GLP-1 medications and gallstones — full guide →

The MJA September 2025 consensus statement recommends MASLD assessment for all GLP-1 patients with metabolic risk factors. This applies regardless of which injection you take.

The recommended Australian pathway:

1. FIB-4 score from routine blood tests (ALT, AST, platelets, age) — no additional cost if bloods are already done
2. Liver elastography (FibroScan or guided transient elastography) if FIB-4 is indeterminate (1.3–2.67) or if you have metabolic risk factors
3. Annual liver function tests during treatment, with repeat elastography at 12 months to assess liver fat and fibrosis response

Several Australian clinics accept self-referral for liver elastography — you do not always need a specialist referral to book a baseline scan.

FibroScan in Australia — costs and clinics →

Find a liver elastography clinic near you →

Cost is often the deciding factor. Current approximate monthly costs at maintenance dose:

• Ozempic (PBS, T2D): $31.60 per prescription (~$120–$180/month depending on dose and pharmacy)
• Ozempic (private, off-label weight loss): $150–$250/month
• Wegovy (private): $300–$395/month
• Wegovy (PBS, narrow eCVD listing): $31.60 per prescription if eligible
• Mounjaro (private): $285–$690/month depending on dose

Add liver monitoring costs: FIB-4 is free from existing bloods; elastography is typically $150–$300 per scan at private Australian clinics.

Wegovy PBS status — who qualifies →