Fast comparison: which helps people lose more weight on average?
- Average results: Wegovy ~15% at 68 weeks (STEP-1); Mounjaro up to ~22.5% at 72 weeks on 15 mg (SURMOUNT-1).
- Head-to-head: Tirzepatide ~20.2% vs Semaglutide 2.4 mg ~13.7% at 72 weeks (SURMOUNT-5).
- Mechanism: Wegovy is a GLP-1 receptor agonist; Mounjaro is a dual GIP/GLP-1 agonist.
- Dosing cadence: Both are weekly with gradual dose escalation to improve tolerability.
- Tolerability: GI side effects are common for both; slow titration and dietary changes help.
- Australia: Weight management use is typically private prescription; supply and cost vary by pharmacy.
Average weight loss results in clinical trials
Wegovy (semaglutide 2.4 mg)
- STEP-1 trial (people with obesity/overweight without diabetes): ~14.9–15% average loss at 68 weeks with lifestyle support.
- High proportion achieved ≥5%, ≥10% and ≥15% loss compared with placebo.
Mounjaro (tirzepatide)
- SURMOUNT-1 (without diabetes): up to ~22.5% average loss at 72 weeks on 15 mg; ~20.9% on 10 mg; ~15% on 5 mg.
- Head-to-head SURMOUNT-5: tirzepatide ~20.2% vs semaglutide 2.4 mg ~13.7% at 72 weeks.
Important: These are averages under clinical supervision with diet and activity support. Individual responses vary by dose, adherence, side effects, and health status.
How Wegovy and Mounjaro work
- Wegovy: GLP-1 receptor agonist (semaglutide) slows gastric emptying, reduces appetite and cravings, and supports lower caloric intake.
- Mounjaro: Dual GIP/GLP-1 receptor agonist (tirzepatide) combines pathways that appear to further suppress appetite and may enhance metabolic effects, which likely contributes to higher average weight loss in trials.
GLP-1 Australia Guide for background on this class.
Dosing and titration
Wegovy weekly escalation
- Typical schedule: 0.25 mg → 0.5 mg → 1.0 mg → 1.7 mg → 2.4 mg (each step usually 4 weeks apart).
- If side effects occur, prescribers may pause or step back before re-escalation.
Mounjaro weekly escalation
- Common schedule: 2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg (step-up typically every 4 weeks).
- Target dose depends on response and tolerability; not all patients need the highest dose.
Side effects, safety and who should avoid them
Common side effects
- Both: nausea, vomiting, diarrhoea, constipation, bloating, reflux, reduced appetite.
- Tips: slower titration, smaller meals, higher protein, low-fat meals during escalation, hydration, avoid overeating.
Serious risks and warnings
- Possible risks: pancreatitis, gallbladder issues, severe GI symptoms, dehydration, kidney issues in susceptible patients.
- Contraindications: personal/family history of medullary thyroid carcinoma (MTC) or MEN2; avoid in pregnancy and typically during breastfeeding.
- Interactions and comorbidities should be reviewed with a prescriber (especially diabetes medications).
Cardiovascular data: semaglutide has demonstrated cardiovascular risk reduction in certain high-risk groups; cardiovascular outcomes data for tirzepatide are emerging.
How quickly results appear
- Weeks 1–4: appetite and portion changes often begin during the first dose steps.
- Months 2–3: steadier fat loss as doses approach maintenance.
- Months 6–12: cumulative weight loss; lifestyle support remains critical for long-term results.
Access, cost and availability in Australia
- Regulatory status: Wegovy (semaglutide) is approved for weight management; tirzepatide (Mounjaro) is approved for diabetes, with weight-management branding and availability evolving.
- PBS: generally limited to diabetes indications; weight-loss use usually requires a private prescription.
- Costs: private pricing varies by dose, brand and pharmacy; supply can fluctuate.
Wegovy Australia Guide | Mounjaro Australia Guide
Wegovy Cost Australia | Mounjaro Cost Australia
Wegovy Prescription Australia | Mounjaro Prescription Australia
Wegovy vs Mounjaro: which is better for you?
- If maximum average weight loss is your priority: tirzepatide has shown greater averages in trials and head-to-head comparisons.
- If you prefer a more established cardiovascular evidence base: semaglutide currently has broader CV outcomes data.
- If you’re sensitive to GI side effects: either can work with slower titration; some patients tolerate one better than the other.
- If you also have type 2 diabetes: tirzepatide and semaglutide both improve glycaemic control; discuss which integrates best with your regimen.
- Access and cost: availability, pharmacy pricing and PBS eligibility may steer the practical choice.
Semaglutide vs Tirzepatide: Deeper Comparison
Frequently asked questions
Which works better for weight loss on average?
In head-to-head data, tirzepatide produced higher average loss (~20.2% vs ~13.7% with semaglutide 2.4 mg at 72 weeks). Individual responses vary.
How long should I stay on treatment?
Trials ran for 68–72 weeks. Long-term management plans are individual and depend on goals, side effects, cost, and medical review.
Can I use them without diabetes?
Yes, weight management use is possible; approvals, branding and availability differ. In Australia, weight-loss scripts are typically private.
Do I still need diet and exercise?
Yes. Trials included lifestyle support, which improves results and helps maintain weight loss.
Are there cardiovascular differences?
Semaglutide has demonstrated cardiovascular event reduction in some populations. Tirzepatide CV outcomes data are emerging.
What if I can’t tolerate the target dose?
Many patients do well on intermediate doses. Prescribers can pause or reduce steps to balance efficacy and side effects.
Is this medical advice?
No. This page is general information. Seek personalised guidance from a qualified Australian prescriber.
Get help choosing between Wegovy and Mounjaro
Send a message to get guidance on eligibility, dosing, side effects and local availability in Australia.
Final takeaway
For most people comparing Wegovy vs Mounjaro, tirzepatide shows higher average weight loss in trials, while semaglutide offers strong long-term data and broad clinical experience. The best choice depends on your goals, health history, tolerability, access and budget.