Mounjaro: what you need to know

What Is Mounjaro?

Mounjaro is a prescription medicine that contains the active ingredient tirzepatide. It belongs to a group of medicines known as GIP and GLP-1 receptor agonists and is manufactured by Eli Lilly and Company.

In December 2025, Medsafe authorised Mounjaro for use in New Zealand for both type 2 diabetes and chronic weight management in adults. It is supplied as a multi-dose, pre-filled injection pen and is taken once a week.

Because Mounjaro is a prescription medicine, it should only be used under the supervision of a healthcare provider. They will assess whether it is appropriate for your individual situation.

How Does Mounjaro Work?

Mounjaro works by activating two natural hormone pathways in the body: GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1). These hormones play a role in regulating blood sugar levels and appetite.

By targeting both GIP and GLP-1 receptors, Mounjaro helps the body release insulin when blood sugar levels rise and helps limit the amount of glucose the liver releases into the bloodstream. It also slows how quickly food leaves the stomach and influences signals in the brain that affect hunger and fullness.

Together, these actions can help improve blood sugar control in people with type 2 diabetes and support weight loss when used as part of a broader weight management plan.

Mounjaro for Weight Management

Mounjaro is also approved in New Zealand for chronic weight management in adults who are overweight or living with obesity. It is intended to be used alongside a reduced-energy diet and increased physical activity.

By influencing appetite, slowing digestion, and helping regulate blood sugar, Mounjaro can support gradual weight loss over time. Some people may also use it to help maintain weight loss once it has been achieved.

Health New Zealand | Te Whatu Ora recommends balanced eating patterns and regular physical activity as the foundation of long-term weight management. More information is available on the Health New Zealand website.

Weight loss results vary from person to person. Individual responses vary, and maintaining healthy lifestyle habits remains important over the long term.

Who May Be Eligible for Mounjaro?

Mounjaro may be considered for adults with type 2 diabetes who need support to improve their blood sugar control. It may be used on its own or alongside other diabetes medicines, depending on your individual treatment plan.

For weight management, Mounjaro is approved for adults who are overweight or living with obesity. Your healthcare provider will review your overall health, past medical history, and treatment objectives to determine whether Mounjaro is right for you.

Because Mounjaro is a prescription medicine, suitability is decided on an individual basis. Your healthcare provider will consider any existing health conditions, other medicines you are taking, and potential risks before prescribing it.

Who Should Not Use Mounjaro?

You should not use Mounjaro if you are allergic to tirzepatide or any of its ingredients.

Mounjaro should not be used during pregnancy. If you are pregnant, intend to become pregnant, or there is a possibility you could be pregnant, speak with your healthcare provider before starting treatment.

Mounjaro is not approved for use in children or adolescents under 18 years of age.

In some situations, Mounjaro may still be prescribed, but extra care or monitoring may be needed. Tell your healthcare provider if you:

Because Mounjaro slows digestion, it can affect how some medicines taken by mouth work. This includes oral contraceptive pills. Your healthcare provider may recommend an additional or different form of contraception when starting Mounjaro or after increasing your dose.

Your healthcare provider will review your health history and current medicines before deciding whether Mounjaro is right for you.

• Have severe digestive problems, including delayed stomach emptying (gastroparesis)
• Have had pancreatitis (inflamed pancreas)
• Have diabetes-related eye problems
• Have heart failure
• Have kidney or liver problems
• Have experienced thoughts of self-harm or suicide
• Are taking insulin or certain other diabetes medicines that can cause low blood sugar

What Results Might Be Expected?

People using Mounjaro for type 2 diabetes may notice improvements in their blood sugar levels over time. Your healthcare provider will usually monitor your HbA1c and other blood sugar readings to assess how well the medicine is working. The pace and extent of improvement can vary from person to person.

For those using Mounjaro for weight management, gradual weight loss may occur as treatment continues. In clinical studies, many participants experienced meaningful reductions in body weight when Mounjaro was used alongside changes in diet and physical activity. However, results are not the same for everyone.

Some people notice changes within the first few weeks, while for others it may take longer. Consistency with weekly dosing and maintaining healthy lifestyle habits remain important factors in achieving and sustaining progress.

How Is Mounjaro Taken?

Mounjaro is given as a once-weekly injection under the skin, using a pre-filled pen. You can take it at any time of day, with or without food.

Treatment usually begins at a lower dose, which is gradually increased over time. Increasing the dose gradually gives your body time to adapt and may lower the chance of unwanted side effects. The maximum recommended dose in New Zealand is 15 mg once weekly.

For more detailed information about dosing schedules, missed doses, and how to use the injection pen, see our comprehensive Mounjaro dosage guide.

It is important to use Mounjaro exactly as prescribed and not to change your dose without medical advice.

Will I Need to Pay for Mounjaro?

Mounjaro is currently not publicly funded in New Zealand. This means you will need to pay for it yourself. You may also be required to cover any consultation costs with your healthcare provider. Your pharmacist can advise you on current availability and pricing.

What Are the LongTerm Effects of Mounjaro Use?

Mounjaro may be used for an extended period where appropriate, and ongoing treatment should be reviewed regularly by a healthcare provider.

As with many newer medicines, safety information is collected over time. The side effects currently described in the New Zealand Consumer Medicine Information can happen at any stage of treatment, and regular monitoring is important to ensure the medicine remains suitable.

If you are considering long-term use, your healthcare provider will assess the potential benefits and risks based on your individual health circumstances and how well you are tolerating treatment.

A Final Word

Mounjaro may be a helpful treatment option for some adults living with type 2 diabetes or for those seeking support with chronic weight management, but may not be suitable for everyone. Your medical history, current health conditions, and personal circumstances will all influence whether it’s the right choice.

Before starting treatment, it’s important to share your full medical history with your healthcare provider. This includes any past or existing health conditions, family medical history, and all medicines you are currently taking.

By having an open and informed discussion, you and your healthcare provider can decide on a treatment plan that is safe, appropriate, and aligned with your individual health needs.

Important safety information

Prescription medicine. Mounjaro® is approved in New Zealand for improving blood sugar control in adults with type 2 diabetes, as an adjunct to diet and exercise, and for chronic weight management in adults with obesity, or overweight with at least one weight-related comorbidity, in conjunction with a reduced-energy diet and increased physical activity. Mounjaro® contains the active ingredient tirzepatide and is available as a solution for injection in a pre-filled pen (2.5 mg/0.5 mL, 5 mg/0.5 mL, 7.5 mg/0.5 mL, 10 mg/0.5 mL, 12.5 mg/0.5 mL and 15 mg/0.5 mL). Mounjaro® has risks and benefits. Ask your healthcare provider if Mounjaro® is right for you. Use strictly as directed. If you experience side effects, see your doctor, pharmacist, or healthcare professional. For more information, see the Consumer Medicine Information (tirzepatide) available at: https://www.medsafe.govt.nz/Consumers/cmi/m/Mounjaro.pdf