Retatrutide vs Mounjaro vs Ozempic: what's the difference?

What is the difference between retatrutide, Mounjaro, and Ozempic?

Retatrutide, Mounjaro, and Ozempic differ in three ways: the molecule inside each one, which hormone receptors its description names, and whether any regulator has approved it. The US Ozempic label describes semaglutide as a GLP-1 receptor agonist (GLP-1, glucagon-like peptide-1, is the fullness signal). The US Mounjaro label describes tirzepatide as a GIP receptor and GLP-1 receptor agonist (GIP, glucose-dependent insulinotropic polypeptide, is the meal-and-insulin signal). Retatrutide has no label: its developer's 2022 paper titles it a triple glucagon, GIP and GLP-1 receptor agonist, an in vitro receptor-assay description that does not establish effects in people (Coskun et al., Cell Metabolism, 2022). The TGA states that retatrutide is in clinical trials and has not been approved by the TGA or any comparable regulator (TGA safety alert, 14 September 2026).

Glucagon behaves differently from GLP-1 and GIP: it is the signal your liver listens for when food has stopped arriving and stored energy needs releasing.

Is retatrutide the same as Mounjaro?

Retatrutide is not the same molecule as Mounjaro. Mounjaro is a prescription medicine first registered on the Australian Register of Therapeutic Goods on 23 December 2022 (TGA AusPAR, 20 September 2024) and carrying initial US approval from 2022 (US Mounjaro label, DailyMed, 2 September 2026). Its active ingredient is tirzepatide, a 39-amino-acid peptide (Coskun et al., Molecular Metabolism, 2018) that the US Mounjaro label describes as a GIP receptor and GLP-1 receptor agonist. Zepbound is a second US-labelled medicine built on that same tirzepatide molecule (US Zepbound label, DailyMed, 2 September 2026). Retatrutide is a separate experimental peptide, with a different amino-acid sequence and a different research code.

Both compounds share a developer, which is exactly why the names get tangled. A shared developer is not a shared molecule. The pattern in the family tree is worth noticing, though: the locks never change. They are the gut-hormone signals your body has used after every meal of your life. What changes is the key.

Is Mounjaro the same molecule as Ozempic?

Mounjaro and Ozempic are different medicines with different active molecules. The US Ozempic label and US Wegovy label list semaglutide as the active ingredient, which the Ozempic label describes as a GLP-1 receptor agonist. The US Mounjaro label and US Zepbound label list tirzepatide, which the Mounjaro label describes as a GIP receptor and GLP-1 receptor agonist. In SURPASS-2, an open-label, 40-week trial of 1,879 adults with type 2 diabetes funded by the tirzepatide developer, the estimated HbA1c (a three-month blood-sugar marker) change was -2.30 points in the highest tirzepatide trial arm against -1.86 points with semaglutide, a result for that population only (Frias et al., New England Journal of Medicine, 2021).

Those numbers belong to the trial that produced them and nowhere else. SURPASS-2 compared tirzepatide with semaglutide in diagnosed patients, under clinical supervision, against one blood marker chosen before the trial began. That is a narrow question, answered carefully. It is not a league table of molecules.

Which is better, retatrutide or Mounjaro?

The TRIUMPH-5 registry record checked on 14 October 2026 had no posted head-to-head result, so it cannot establish which is better. TRIUMPH-5 (NCT06662383), a registered head-to-head trial of retatrutide against tirzepatide, the molecule in Mounjaro, enrols 800 adults and lists its primary completion as estimated for November 2026. Indirect estimates link separate trials through placebo. A 2026 network meta-analysis of 58 randomised trials in 24,214 adults without diabetes put placebo-subtracted weight loss at -22.10% for retatrutide (95% confidence interval -25.60% to -18.60%) and -19.28% for tirzepatide (-20.39% to -18.16%), intervals that overlap, and its authors note limited head-to-head evidence (Chen et al., BMJ Medicine, 2026).

Tirzepatide's record is far longer. Mounjaro has a US label with initial approval in 2022 (US Mounjaro label, DailyMed, 2 September 2026), and the TGA states that retatrutide has not been approved by the TGA or any comparable regulator (TGA safety alert, 14 September 2026). A 2026 systematic review of 38 randomised trials in 25,816 adults with overweight or obesity without diabetes gave placebo-subtracted weight loss of up to -22.1% for retatrutide and -19.0% for tirzepatide, and its authors state that heterogeneity precluded quantitative synthesis (Moiz et al., Annals of Internal Medicine, 2026). A 2026 BMJ network meta-analysis of 262 randomised trials (99,791 adults with overweight or obesity) rated tirzepatide's one-year weight loss, 14.9% against lifestyle change alone, as moderate to high certainty, and it grouped retatrutide with two other emerging agents that it said may produce similar or greater reductions, at very low to low certainty (Nong et al., BMJ, 2026).

Side effects count in any comparison. In a network meta-analysis covering 58 trials in 24,214 adults without diabetes, low-certainty indirect evidence suggested higher rates of stopping treatment with retatrutide and better tolerability with mazdutide; its abstract gives no discontinuation-specific count, so the review total does not establish that outcome's denominator (Chen et al., BMJ Medicine, 2026). A question such as why retatrutide is better than tirzepatide assumes a result that no head-to-head trial found for this page has reported. The study findings page lists the registered trials.

Is retatrutide better than Ozempic or semaglutide?

The NCT06260722 registry record checked on 14 October 2026 had no posted head-to-head result for retatrutide against semaglutide, the molecule in Ozempic and Wegovy. A Phase 3 trial in type 2 diabetes, NCT06260722 (1,250 adults, open-label), reached its actual primary completion on 27 August 2026 and has no results posted (ClinicalTrials.gov, checked 14 October 2026). In a 2026 systematic review of 38 randomised trials in 25,816 adults with overweight or obesity without diabetes, placebo-subtracted weight loss reached up to -22.1% for retatrutide and -14.8% for subcutaneous semaglutide, figures from different trials, populations and lengths in a review whose authors state that heterogeneity precluded quantitative synthesis, so they are not a ranking (Moiz et al., Annals of Internal Medicine, 2026).

Retatrutide's cardiovascular and kidney outcomes trial, NCT06383390, is active and not recruiting, with primary completion estimated for February 2029 (ClinicalTrials.gov, checked 14 October 2026).

What is retatrutide similar to?

On receptor description alone, retatrutide is closest to tirzepatide among the medicines on this page. The US Mounjaro label describes tirzepatide as a GIP receptor and GLP-1 receptor agonist, and the developer's 2022 paper titles retatrutide a triple agonist that adds the glucagon receptor, an in vitro receptor-assay description that does not establish effects in people (Coskun et al., Cell Metabolism, 2022). The US Ozempic label describes semaglutide as a GLP-1 receptor agonist. A 2026 meta-analysis of 19 randomised trials in adults with overweight or obesity groups mazdutide, survodutide, cotadutide and efinopegdutide as dual GLP-1 and glucagon agonists without GIP, a classification from a synthesis whose abstract gives no participant count (Amjad et al., Diabetes, Obesity and Metabolism, 2026). A combination of cagrilintide and semaglutide was also assessed in a network meta-analysis (Chen et al., BMJ Medicine, 2026).

Sport Integrity Australia describes retatrutide as a triple receptor agonist that targets GIP and glucagon receptors in addition to GLP-1, and says it is not on the 2026 World Anti-Doping Agency Prohibited List (checked 14 October 2026). That List's class S0 covers any pharmacological substance with no current governmental approval for human therapeutic use that no other section addresses (WADA Prohibited List 2026, page 4), so a missing name does not establish permission in sport. Similar names and shared receptors do not make two compounds the same thing, and each one needs its own trial record.

Is retatrutide approved for osteoarthritis, and what have trials studied?

No. Retatrutide is approved for no condition, according to the TGA (TGA safety alert, 14 September 2026), and knee osteoarthritis pain is one of the outcomes studied in obesity trials. In TRIUMPH-1, the 574 participants with knee osteoarthritis recorded WOMAC pain scores (a 1 to 10 scale where higher means worse pain) that changed by -3.2 to -3.6 across the three retatrutide arms against -1.9 with placebo, in the paper's hybrid estimand, a subgroup result from a developer-funded obesity trial read from its abstract (Jastreboff et al., New England Journal of Medicine, 2026). A dedicated trial, TRIUMPH-4 (NCT05931367, 445 adults with obesity and knee osteoarthritis), is completed with no results posted (ClinicalTrials.gov, checked 14 October 2026).

A hybrid estimand is a way of handling events such as stopping treatment, and this paper applied a hypothetical strategy to events that suggest treatment failure. In the 574 participants with knee osteoarthritis in the developer-funded TRIUMPH-1 obesity trial, the paper also reports an intention-to-treat result, where the retatrutide arms changed by -3.4 to -4.1 against -2.5 with placebo, a subgroup result read from the abstract that does not describe other participants (Jastreboff et al., NEJM, 2026). Entry to the osteoarthritis subgroup required knee pain for more than 12 weeks and moderate changes on a knee X-ray (ClinicalTrials.gov NCT05929066).

Is a retatrutide clinical trial recruiting in Australia?

One recruiting retatrutide trial lists Australian sites as of 14 October 2026. It is NCT07165028, a Phase 3 trial in adults with metabolic dysfunction-associated steatotic liver disease (MASLD) who are at risk of liver outcomes, and its sites include Fiona Stanley Hospital in Murdoch. Entry rules include liver fat of 8% or more and no other liver disease (ClinicalTrials.gov, checked 14 October 2026). The other five Australian-site records are completed or active and not recruiting. Each trial sets its own rules, and this page is not an invitation to enrol.

The study findings page lists the main registered retatrutide trials with their first-posted dates and status. The registry is the place where a trial's entry rules and contacts are published.

Evidence limits

What has the research not shown yet?

Lining those two percentages up and declaring a winner is the most natural thing in the world to do, and it is the one thing the evidence cannot support. Different trials. Different lengths — 48 weeks against 72. Different people, recruited under different rules. A percentage only means something while it is still attached to the study that produced it.

A third figure gets quoted alongside them. In a smaller imaging study of 98 adults whose liver fat started at 10% or higher, by authors including developer employees, the highest retatrutide trial arm averaged an 82.4% drop in liver fat at 24 weeks, one study, one trial arm, 24 weeks, and far too narrow to build a conclusion on (Sanyal et al., Nature Medicine, 2024). TRIUMPH and TRANSCEND are the Phase 3 programmes that could answer the larger question, and none of their results found for this page is a head-to-head comparison.

Which retatrutide percent is the trial result?

TRIUMPH-1 has two public headline figures, so keep each source beside its number. The June 2026 ADA briefing reports 28.3% average weight loss in the highest trial group. The September 2026 journal summary reports 25.0% for that group. Both describe retatrutide over 80 weeks. A third record, the 2025 design paper, sets out the study plan. It does not report those weight results.

ADA means the American Diabetes Association. Its June briefing does not name the method behind that figure. The September paper names a treatment-regimen estimand: a rule for which outcomes count in the estimate. Different counting rules might explain the gap, but that remains unconfirmed here.

The September paper reports a 3.9% average weight loss with placebo, which has no active drug. These are group averages from Jastreboff and colleagues' NEJM paper, checked 17 October 2026. They cannot predict your own result. Giblin and colleagues' 2025 design paper explains the study questions. A plan cannot supply a result, even when another page cites it.

Is research material a substitute for Mounjaro or Ozempic?

Research-use-only material is not a substitute for Mounjaro or Ozempic. Mounjaro and Ozempic are prescription medicines with US labels, dispensed and supervised. Laboratory reference material is not those medicines, not a cheaper route to them, and not for human or animal use. Where a research compound and a medicine happen to share a molecule, that shared identity is a fact of chemistry and nothing more. Retatrutide has no approved medicine, according to the TGA (TGA safety alert, 14 September 2026), so there is nothing for laboratory material to stand in for.

Price questions land in the same place. What laboratory material costs is a question about synthesis — how long the amino-acid chain is, how pure the finished powder runs, and how much testing sits behind that purity number. It is never a comparison with what a pharmacy charges. This site's retatrutide reference material listing is freeze-dried laboratory stock. Available reports cover historical samples; matching current certification is unverified. Reading that paperwork is a skill of its own — what a certificate of analysis records, what a third-party report proves, how a batch stays traceable — and the quality and verification hub walks through it.