Semaglutide vs Tirzepatide Australia: Which GLP-1 Wins? (2025)

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Tirzepatide produces approximately 6 percentage points more weight loss than semaglutide in clinical trials — 20.9% versus 14.9% average body weight reduction. But in Australia, only semaglutide (Wegovy) has TGA approval for weight management. Tirzepatide (Mounjaro) is TGA-approved for Type 2 diabetes only. This article covers what each compound does differently, what the Australian access picture looks like right now, and which to ask your prescriber about.

Semaglutide vs tirzepatide: the comparison at a glance

	Semaglutide	Tirzepatide
Brand names (AU)	Wegovy, Ozempic	Mounjaro
Mechanism	GLP-1 receptor agonist	Dual GIP + GLP-1 agonist
TGA approval	Weight management (Wegovy, 2024)	Type 2 diabetes only
Weight management access	Approved pathway	Off-label only
Average weight loss	14.9% (STEP 1, 68 weeks)	20.9% (SURMOUNT-1, 72 weeks, 15mg)
PBS listed for weight loss	No	No
Monthly cost AUD	$129–$320	$180–$380 (off-label, compounded)
Prescription required	Yes — AHPRA	Yes — AHPRA
Nausea profile	Common at titration	Similar but may be lower

What does the clinical evidence actually show?

Semaglutide — STEP 1 trial data: The pivotal Phase 3 STEP 1 trial enrolled 1,961 adults with obesity (no Type 2 diabetes). At 68 weeks on 2.4 mg/week semaglutide: average body weight loss of 14.9%, versus 2.4% on placebo. 86.4% of participants lost at least 5% of body weight. The STEP trials established semaglutide as the most evidence-robust weight management medication available.

Tirzepatide — SURMOUNT-1 trial data: The SURMOUNT-1 Phase 3 trial enrolled 2,539 adults with obesity. At 72 weeks on 15 mg/week tirzepatide (highest dose): average weight loss of 20.9%, versus 3.1% on placebo. 91% of participants lost at least 5% of body weight at the highest dose. The superior result is attributable to tirzepatide's dual mechanism — adding GIP agonism to GLP-1.

Why does the GIP receptor make a difference? Semaglutide activates only GLP-1 receptors — slowing gastric emptying, suppressing appetite signalling in the brain, and improving insulin sensitivity. Tirzepatide activates both GLP-1 and GIP receptors. GIP (glucose-dependent insulinotropic polypeptide) has direct effects on adipose tissue — promoting fat oxidation and potentially contributing to better body composition outcomes. GIP also modulates GLP-1 receptor expression, which may partly explain why tirzepatide produces less nausea despite greater efficacy in some patients.

What is semaglutide approved for in Australia?

Semaglutide has two TGA-approved products in Australia with different indications:

Wegovy (2.4 mg/week): TGA-approved since 2024 for chronic weight management in adults with BMI ≥30, or BMI ≥27 with at least one weight-related comorbidity. Not PBS-listed for weight management — full out-of-pocket costs apply.

Ozempic (up to 1 mg/week): TGA-approved and PBS-listed for Type 2 diabetes management only. The PBS subsidy applies to diabetes — not weight loss. Off-label weight loss use is legal but not subsidised.

Access is straightforward: AHPRA-registered GP or telehealth practitioner, prescription to a licensed compounding or retail pharmacy. Most major Australian telehealth clinics (Juniper, Simple Online Doctor, hub.health, Mosh) have established pathways.

What is tirzepatide approved for in Australia?

Tirzepatide (Mounjaro) received TGA approval for the treatment of Type 2 diabetes in adults as a supplement to diet and exercise. It is not TGA-approved for weight management as of the date of publication. This is a meaningful distinction:

Patients with Type 2 diabetes can access Mounjaro through a standard prescription
Patients without Type 2 diabetes who want tirzepatide for weight management have no approved product
PBS listing for tirzepatide weight management is not available — TGA approval for this indication has not been granted

Writer note: verify TGA approval status for tirzepatide weight management at time of publication — this is subject to change.

Can you get tirzepatide for weight loss in Australia right now?

Some Australian telehealth clinics prescribe compounded tirzepatide off-label for weight management in patients without Type 2 diabetes. This is legal under Australian prescribing regulations — AHPRA-registered practitioners can prescribe off-label when they judge it clinically appropriate for the individual patient.

Practical implications:

Not all clinics offer this — it requires a practitioner willing to prescribe off-label
Compounded tirzepatide (not Mounjaro brand) is prepared by a licensed Australian compounding pharmacy
Higher cost than semaglutide: $180–$380 AUD/month vs $129–$320 for semaglutide
The regulatory environment for compounded GLP-1 agents is under active TGA review — this access pathway may change

Compare Australian clinics offering GLP-1 weight management programs →

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Head-to-head on cost in Australia

Semaglutide (starting dose, 0.25 mg/week): $129–$180 AUD/month at subscription-model clinics (Juniper, Simple Online Doctor, hub.health).

Semaglutide (maintenance dose, 1.7–2.4 mg/week): $200–$320 AUD/month.

Tirzepatide (off-label compounded, starting dose): $180–$250 AUD/month.

Tirzepatide (off-label compounded, maintenance dose): $280–$380 AUD/month.

The cost premium for tirzepatide ($50–$100/month above semaglutide) reflects the more complex synthesis and limited compounding competition relative to semaglutide. This gap is likely to narrow as more compounders enter the market.

Our recommendation: which to ask your prescriber about

For most Australians: Semaglutide (Wegovy/compounded) is the right starting point. TGA-approved, strong evidence base, accessible through multiple telehealth clinics, lower cost, and the most Australian practitioner experience behind it.

If body composition matters more than scale weight: Tirzepatide's GIP agonism shows more favourable body composition changes in early data — less lean mass loss relative to fat loss. If you're active and want to preserve muscle during weight loss, discuss tirzepatide with a practitioner willing to prescribe off-label.

If you've tried semaglutide without sufficient response: Tirzepatide is the evidence-based escalation option. The SURMOUNT trials show meaningful additional weight loss in populations who were previous GLP-1 partial responders.

Neither drug is appropriate without clinical monitoring. Both require baseline blood work and regular follow-up.

ProtocolHub provides educational information only. All GLP-1 therapies require consultation with an AHPRA-registered medical practitioner. This does not constitute medical advice.

Semaglutide vs Tirzepatide in Australia: The Weight Loss Results Are Striking — But the Access Is Completely Different