Mounjaro vs Ozempic: Weight Loss, Diabetes and Cost Compared

Weight loss results compared

Tirzepatide (Mounjaro/Zepbound):

• SURPASS‑2 (T2D; tirzepatide vs semaglutide 1 mg): Tirzepatide led to larger body‑weight reductions (approx. −7.6 to −11.2 kg depending on 5–15 mg) vs −5.7 kg with semaglutide 1 mg at 40 weeks, and greater HbA1c reductions [NEJM 2021].
• SURMOUNT‑1 (obesity without diabetes): Mean weight loss ~15% (5 mg), ~19.5% (10 mg) and ~20.9% (15 mg) at 72 weeks vs 3.1% with placebo [NEJM 2022].
• SURMOUNT‑2 (obesity with T2D): Mean weight loss ~13–15% at 72 weeks vs 3–4% with placebo [NEJM 2023].

Semaglutide (Ozempic/Wegovy):

• Ozempic 1 mg (T2D): Typically ~4–6 kg average loss across SUSTAIN programme, dose and baseline dependent.
• STEP‑1 (Wegovy 2.4 mg; obesity without diabetes): Mean weight loss 14.9% at 68 weeks vs 2.4% with placebo [NEJM 2021].

Interpretation: For people prioritising weight loss alone, tirzepatide generally produces greater mean loss than semaglutide 1 mg. For obesity without diabetes with published outcomes data, semaglutide 2.4 mg (Wegovy) and tirzepatide (Zepbound) both show large reductions; head‑to‑head obesity trials are not yet published.

See semaglutide vs tirzepatide weight loss detail Ask about a safe starting dose

Diabetes control (HbA1c, glucose)

• SURPASS‑2: Tirzepatide lowered HbA1c by −2.0 to −2.3% vs −1.86% with semaglutide 1 mg at 40 weeks, and more participants reached HbA1c <7% [NEJM 2021].
• SUSTAIN (semaglutide): Robust HbA1c reductions across multiple T2D populations, with additional weight loss vs comparators [programme summary; NEJM].

Clinical takeaway: For T2D needing larger HbA1c and weight improvements in one agent, tirzepatide may have an edge; individual response, tolerability and access still decide.

Tirzepatide for type 2 diabetes Ozempic Australia guide

Cardiovascular outcomes

• Semaglutide:
  • SUSTAIN‑6 (T2D): 26% relative reduction in major adverse cardiovascular events (MACE); HR 0.74 (95% CI 0.58–0.95) vs placebo [NEJM 2016].
  • SELECT (overweight/obesity, no diabetes): 20% MACE reduction with semaglutide 2.4 mg; HR 0.80 (95% CI 0.72–0.90) [NEJM 2023].
• Tirzepatide: A dedicated cardiovascular outcomes trial (SURPASS‑CVOT) has been in progress. At our last update, peer‑reviewed CVOT results were not yet fully published. Clinicians should consider existing semaglutide outcomes data when CV risk is a major driver.

Discuss your CV risk and medicine choice

Dosing, titration and devices

• Ozempic (semaglutide, weekly pen): Start 0.25 mg weekly 4 weeks → 0.5 mg → consider 1 mg (or 2 mg where appropriate). Wegovy uses a separate 2.4 mg titration schedule for obesity.
• Mounjaro (tirzepatide, weekly pen): Start 2.5 mg weekly 4 weeks → 5 mg → then step‑up by 2.5 mg increments (7.5, 10, 12.5, 15 mg) as tolerated and clinically indicated.
• Both are injected subcutaneously once weekly; rotate sites and pair with nutrition, movement and sleep strategies for best outcomes.

Semaglutide dosage guide Tirzepatide dosage guide

Side effects and key safety differences

Common to both: nausea, vomiting, diarrhoea/constipation, reduced appetite, reflux. Usually mitigated by slow titration, smaller/earlier meals, adequate fluids and fibre.

Important cautions and differences:

• Diabetic retinopathy risk (semaglutide): Rapid HbA1c reductions can transiently worsen pre‑existing diabetic retinopathy; monitor closely if baseline retinopathy is present (SUSTAIN‑6 signal).
• Severe GI disease/gastroparesis: Avoid in known severe GI motility disorders; GLP‑1/GIP agonists slow gastric emptying.
• Pancreatitis and gallbladder disease: Stop and evaluate if severe abdominal pain occurs; history of pancreatitis requires careful risk–benefit discussion.
• Renal considerations: Dehydration from GI effects can worsen renal function; maintain fluids and monitor in CKD.
• Thyroid C‑cell tumours: Contraindicated with personal/family history of medullary thyroid carcinoma or MEN2.
• Pregnancy and breastfeeding: Not recommended. Planning pregnancy typically requires stopping semaglutide at least 2 months prior and tirzepatide at least 1 month prior. Use effective contraception and obtain individual medical advice.
• Other medicines: Delayed gastric emptying can alter absorption of oral drugs with a narrow therapeutic index; review your medication list with a prescriber.

Ozempic side effects Mounjaro side effects

Cost in Australia (private and PBS)

Indicative private pharmacy pricing (varies by pharmacy, dose and stock). Monthly totals assume one pen per 4 weeks at the stated dose:

• Ozempic (semaglutide for T2D):
  • 0.25–0.5 mg weekly: approximately $130–$170 per month.
  • 1 mg weekly: approximately $130–$170 per month (higher‑strength pen may change cost).
  • 2 mg weekly: approximately $180–$230 per month.
• Mounjaro (tirzepatide for T2D):
  • 2.5–5 mg weekly: approximately $310–$360 per month.
  • 7.5–10 mg weekly: approximately $330–$420 per month.
  • 12.5–15 mg weekly: approximately $350–$450 per month.

PBS co‑payments for eligible T2D prescriptions: general patient co‑pay typically around $31–$32 per script and concessional around $7–$8 per script at the time of our last update. Check current amounts with Services Australia and your pharmacist.

PBS eligibility (summary, check item rules):

• Confirmed diagnosis of type 2 diabetes mellitus.
• Inadequate glycaemic control on lifestyle plus first‑line therapy (commonly metformin) unless contraindicated/intolerant.
• Use as an adjunct to diet and exercise, often in combination with other glucose‑lowering agents per PBS restriction wording.
• Not for type 1 diabetes or diabetic ketoacidosis.

PBS references: PBS Ozempic listings • PBS Mounjaro listings

Ask us to estimate your monthly cost Ozempic cost guide Mounjaro cost guide

Australian approvals and availability

• Ozempic (semaglutide 0.25–2 mg): TGA‑approved for T2D and PBS‑listed for eligible patients. Australia experienced supply shortages; see TGA advisories and check local pharmacy stock. TGA: semaglutide ARTG search • Ozempic shortage notice
• Mounjaro (tirzepatide 2.5–15 mg): TGA‑approved for T2D and PBS‑listed for eligible patients. TGA: tirzepatide ARTG search
• Wegovy (semaglutide 2.4 mg for obesity): TGA‑approved for chronic weight management in adults with BMI‑based criteria; not PBS‑listed. Initial Australian supply has been staged with ongoing constraints; see our Wegovy guides for updates.
• Zepbound (tirzepatide for obesity): TGA‑approved for chronic weight management. At last update, national availability remained limited and not PBS‑listed; check pharmacy channels and TGA notices for timing and stock updates.

Wegovy Australia guide Mounjaro Australia guide

Who may prefer which option?

• Prioritising maximum weight loss with T2D: Tirzepatide (Mounjaro) often yields larger mean weight and HbA1c reductions vs semaglutide 1 mg (SURPASS‑2).
• Established CV outcomes evidence needed now: Semaglutide has published MACE reduction in T2D (SUSTAIN‑6) and in those with overweight/obesity without diabetes (SELECT).
• Obesity without diabetes: Wegovy (semaglutide 2.4 mg) and Zepbound (tirzepatide) are the indicated brands. Choice depends on access, tolerability and clinician advice.
• GI tolerability challenges or retinal disease history: Semaglutide requires specific retinopathy monitoring; both need slow titration and supportive care to reduce nausea.

Get a tailored recommendation

Safe switching between semaglutide and tirzepatide

Only switch under clinician supervision. A conservative framework often used in practice:

• Semaglutide → Tirzepatide: Give approximately 1 week after the last semaglutide dose, then start tirzepatide 2.5 mg weekly and re‑titrate (2.5 → 5 → 7.5 mg, etc.) based on tolerance and glucose control.
• Tirzepatide → Semaglutide: Give approximately 1 week after the last tirzepatide dose, then start semaglutide 0.25 mg weekly and re‑titrate (0.25 → 0.5 → 1 mg; Wegovy schedule differs).
• Monitor GI symptoms, glucose, and (if applicable) retinopathy. Adjust other glucose‑lowering agents as needed to reduce hypoglycaemia risk.

Ozempic prescription in Australia Mounjaro prescription in Australia

How to access legally and safely in Australia

• Consult an Australian‑registered prescriber (in‑clinic or telehealth). Assessment includes medical history, medications, pregnancy planning and CV risk.
• Use TGA‑approved brands dispensed by Australian pharmacies. Avoid grey‑market or compounded substitutes where a standard product exists, unless specifically advised by your prescriber.
• Prioritise lifestyle supports (nutrition, activity, sleep, psychology) to improve results and minimise side effects.

Buy semaglutide: legal routes Buy tirzepatide: legal routes Talk to a GLP‑1 prescriber

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Complete this form to request guidance on Mounjaro vs Ozempic, PBS eligibility, and safe dosing. A clinician‑led service will contact you by phone or email.

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Medical disclaimer

This page is for general education about “mounjaro vs ozempic” and related Australian access pathways. It is not personal medical advice. Decisions about prescription medicines must be made with a qualified prescriber who understands your medical history, medications, pregnancy plans and risks. If you have alarming symptoms, seek urgent medical care.

Key sources and guidance

• Frías JP et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS‑2). NEJM 2021. https://www.nejm.org/doi/full/10.1056/NEJMoa2107519
• Jastreboff AM et al. Tirzepatide Once Weekly for Obesity (SURMOUNT‑1). NEJM 2022. https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
• Frias JP et al. Tirzepatide in Obesity with Type 2 Diabetes (SURMOUNT‑2). NEJM 2023. https://www.nejm.org/doi/full/10.1056/NEJMoa2307563
• Wilding JPH et al. Once‑Weekly Semaglutide in Adults with Overweight or Obesity (STEP‑1). NEJM 2021. https://www.nejm.org/doi/full/10.1056/NEJMoa2032183
• Marso SP et al. Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN‑6). NEJM 2016. https://www.nejm.org/doi/full/10.1056/NEJMoa1611925
• SELECT Trial Investigators. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. NEJM 2023. https://www.nejm.org/doi/full/10.1056/NEJMoa2314253
• TGA Ozempic shortage notices. https://www.tga.gov.au/news/safety-alerts/shortage-of-ozempic-semaglutide
• TGA ARTG public summaries: Semaglutide. https://www.tga.gov.au/resources/artg?search=semaglutide
• TGA ARTG public summaries: Tirzepatide. https://www.tga.gov.au/resources/artg?search=tirzepatide
• PBS medicines search: Ozempic. https://www.pbs.gov.au/pbs/search?term=Ozempic
• PBS medicines search: Mounjaro. https://www.pbs.gov.au/pbs/search?term=Mounjaro