An investigational peptide that activates GLP-1, GIP and glucagon receptors. It is being studied for obesity and type 2 diabetes and is not currently approved for general human use.

Is Retatrutide legal in Australia?

Retatrutide is not registered on the ARTG and is not approved by the TGA for general use. Access outside an approved clinical trial is generally not lawful. Regulations can change — check current TGA guidance.

Is Retatrutide approved for human use?

Not at the time of this review. It remains investigational pending Phase III completion and regulatory submissions.

How does Retatrutide compare to Semaglutide?

In published trial data, retatrutide produced greater mean weight loss than semaglutide. Long-term safety and durability data are still emerging.

Verified Peptide ReviewLast reviewed: 12 May 2026

Compound Profile · Metabolic

Retatrutide

Name: Retatrutide Review
Item: Retatrutide
Rating: 4.8
Author: Peptide Reviews Editorial Team

Retatrutide is a triple hormone receptor agonist targeting GLP-1, GIP and glucagon receptors. Clinical research shows exceptional results for weight loss and metabolic improvement.

LegalInvestigationalEvidenceStrongHuman useRestricted

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9.6/ 10

Peptide Score

Evidence

9.6

Safety

9.2

Regulatory

9.4

Transparency

9.2

Quick verdict

Strongest weight-loss results of any peptide in trials so far. But still investigational — not approved by the TGA, with long-term safety data still being collected.

Reality check

What this isn't

Not approved by the TGA
Phase II trial data only — Phase III ongoing
Gastrointestinal side effects common (nausea, diarrhoea)
Long-term safety data limited
Cardiovascular outcomes not yet established
Educational research review only — not medical advice

Results snapshot

~24%

Mean weight loss (top dose, 48 wks)

Weeks

338

Participants

Phase II

Trial phase

What this means: Reported reductions exceed any GLP-1 class peptide tested to date. Phase III trials are ongoing — these numbers are not final and have not been replicated long-term.

Reported timeline

What participants experienced

1
Week 0–4
Dose titration; gastrointestinal tolerability emerges as primary side-effect signal
2
Week 8–12
Reported appetite changes; early weight reductions
3
Week 24
Substantial weight loss in mid-to-high dose cohorts; metabolic markers (HbA1c, lipid profile) improving
4
Week 48
Peak reported reductions; weight-loss curve still trending downward at trial end
5
Beyond Week 48
Phase III data collecting — durability, cardiovascular outcomes and long-term safety unknown

01
Week 0–4
Dose titration; gastrointestinal tolerability emerges as primary side-effect signal
02
Week 8–12
Reported appetite changes; early weight reductions
03
Week 24
Substantial weight loss in mid-to-high dose cohorts; metabolic markers (HbA1c, lipid profile) improving
04
Week 48
Peak reported reductions; weight-loss curve still trending downward at trial end
05
Beyond Week 48
Phase III data collecting — durability, cardiovascular outcomes and long-term safety unknown

Deep dive

Full Retatrutide review

Retatrutide is a novel investigational peptide that activates three key hormone receptors: GLP-1, GIP and glucagon. This unique mechanism may lead to greater improvements in weight loss, blood sugar control and metabolic health.

It is being studied in late-stage clinical trials for obesity and type 2 diabetes. As of the last update, retatrutide is investigational and not approved for human use outside a clinical setting.

Retatrutide research hub

20 more articles on Retatrutide

Visit the hub

Mechanism

How Retatrutide Works: A Triple Hormone Receptor Agonist Explained

Mechanism

GLP-1, GIP and Glucagon: The Three Receptors Retatrutide Targets

Mechanism

Triple Agonism vs Dual Agonism: Why Retatrutide Is Different

Mechanism

The Mechanism of Retatrutide-Induced Weight Loss

Evidence

Retatrutide Phase 2 Trial: A Detailed Summary

Evidence

Retatrutide Phase 3 Trials: What's Coming and When

Alternatives

Looking at alternatives?

Compounds with comparable research interest but different evidence, regulatory status, or risk profile.

Metabolic

Semaglutide

Why consider it: Approved in Australia for type 2 diabetes and weight management. Smaller effect size than retatrutide, but multi-year safety data and cardiovascular outcome evidence (SELECT).

View profile

Metabolic

Tirzepatide

Evidence

4.6/ 5

LegalApproved (AU)

Why consider it: Approved in Australia. Dual GIP/GLP-1 mechanism. Currently the strongest approved-medicine option for weight loss in head-to-head data.

View profile

Metabolic

Liraglutide

Why consider it: Older, longer-track-record GLP-1 receptor agonist. Smaller effect size, but the most extensive real-world safety record in the class.

View profile