Zepbound in Australia: the same active ingredient as Mounjaro, a different brand.

Zepbound is a brand name, not a different medicine. It is what Eli Lilly calls tirzepatide in the United States when it is prescribed for chronic weight management.

The US Food and Drug Administration (FDA) approved Zepbound on 8 November 2023 for adults with a BMI of 30 or more, or a BMI of 27 or more with at least one weight-related condition. In the same announcement, the FDA said Zepbound should not be used with Mounjaro or with another GLP-1 receptor agonist. That warning makes sense once you know both names contain the same active ingredient.

Tirzepatide works on two hormone receptors, GIP and GLP-1, which is why it is sometimes described as a "dual agonist". The newer investigational medicine retatrutide adds a third receptor, glucagon; our retatrutide vs tirzepatide explainer covers that comparison. For how tirzepatide acts on appetite and blood sugar, see how Mounjaro works.

Medicine companies often use different brand names in different markets or for different uses. The name on the box tells you who markets it and where; the active ingredient tells you what it is.

In Australia, tirzepatide is supplied under the brand name Mounjaro. Zepbound is the US brand name. Australian supply is the Mounjaro KwikPen from Eli Lilly Australia, used for both type 2 diabetes and weight management.

Every Australian record we checked for this page uses the Mounjaro name: the PBS medicine status page for tirzepatide, the September 2026 Mounjaro KwikPen CMI, and RACGP newsGP reporting on the TGA's weight-management decision. We did not locate a Zepbound entry in the material we reviewed, but we have not been able to confirm its absence from a TGA page, so we do not state that as a fact. If you want to check a product name yourself, the TGA's Australian Register of Therapeutic Goods (ARTG) is the official source.

Practically, this means an Australian looking for information on "Zepbound" is usually looking for information on Mounjaro. The Australian Product Information and CMI for Mounjaro are the documents that apply here, rather than US Zepbound labelling, which is written for a different regulator and market.

The KwikPen itself is relatively new. According to newsGP, it was registered in 2024 and replaced single-use vials in Australia.

Six strengths, from 2.5 mg to 15 mg per weekly dose. Each dose is 0.6 mL, and each KwikPen is "a multiple-dose (4 doses), pre-filled Pen that is used once a week, on the same day each week", according to the CMI.

The CMI describes adults starting at 2.5 mg weekly for 4 weeks, then 5 mg weekly, with the doctor able to increase the dose by 2.5 mg every 4 weeks if needed, to a maximum of 15 mg weekly. For children and adolescents with type 2 diabetes the maximum is 10 mg. The CMI also says to refrigerate pens at 2 to 8 degrees Celsius, not to freeze them, and to keep them in the carton away from light. The full schedule is in our Mounjaro doses guide.

Your prescriber decides the dose. Nothing on this page is a recommendation about which strength, or which brand, suits any individual.

In SURMOUNT-1, adults without diabetes lost an average of 15.0 to 20.9 per cent of body weight over 72 weeks, depending on dose, compared with 3.1 per cent on placebo. These are averages from one trial population, not a prediction for any person.

The figures above use the treatment-regimen estimand, which counts people regardless of whether they stopped treatment: 15.0 per cent on 5 mg, 19.5 per cent on 10 mg and 20.9 per cent on 15 mg. Lilly's efficacy-estimand figures, which estimate the result if everyone had stayed on treatment, were 16.0, 21.4 and 22.5 per cent. The results were published by Jastreboff and colleagues in the New England Journal of Medicine in June 2022.

Because Zepbound and Mounjaro contain the same active ingredient, trial evidence on tirzepatide is relevant to both names. Side effects and precautions for Australians are set out in the Australian CMI; our Mounjaro side effects guide summarises them, and tirzepatide in Australia gives the wider regulatory picture.

No. Food guidance does not depend on the brand name on the pen. What matters for meals is how your appetite and tolerance change day to day, which is a conversation for you, your prescriber and, if you have one, your dietitian.

Many people whose appetite has changed find smaller, protein-forward meals and regular fluids easier to manage than large plates. That is general food information, not a claim that any food changes how a medicine works. Our 7-day Mounjaro food plan, GLP-1 portion guide and protein guide go into detail.