Mounjaro: How It Works and Side Effects
- Canaan Aumua
- Jan 13
- 3 min read
Understanding Mounjaro (Tirzepatide)
Mounjaro, also known by its generic name Tirzepatide, is a new weight loss and diabetes medication developed by Eli Lilly. It’s part of a newer class of drugs that work on multiple hormone pathways to help regulate blood sugar and support weight management. Unlike other GLP-1 medications like Wegovy and Ozempic, Mounjaro also activates GIP (glucose-dependent insulinotropic polypeptide) receptors — which researchers believe may lead to enhanced weight loss and improved metabolic control.
How Mounjaro Works
Tirzepatide works by mimicking two natural hormones involved in appetite regulation and glucose metabolism: GLP-1 (glucagon-like peptide-1) and GIP. These hormones help your body release insulin after eating, slow down gastric emptying (which helps you feel fuller for longer), and reduce appetite.By targeting both pathways, Mounjaro may have a more powerful effect on both blood sugar control and weight loss compared to medications that only activate GLP-1. Clinical trials have shown significant weight reduction in people using tirzepatide, with some patients losing up to 20% of their body weight.
Benefits of Mounjaro for Weight Loss
Mounjaro is currently approved in some countries for the treatment of type 2 diabetes, and it's being evaluated for weight loss in people without diabetes as well. Here’s what early research shows about its benefits:
Substantial weight reduction, especially in higher doses
Improved blood sugar levels
Better appetite control and reduced food cravings
Slower gastric emptying, which helps with satiety
Lowered risk factors for heart disease and metabolic syndrome
Expected Side Effects of Mounjaro
As with other GLP-1 based medications, Mounjaro can cause side effects, especially when starting treatment or increasing your dose. Most side effects are related to the gastrointestinal system and are typically mild to moderate in severity:
Vomiting
Diarrhoea
Constipation
Bloating or abdominal discomfort
Decreased appetite
Nausea
These symptoms often lessen over time as your body adjusts. Starting on a lower dose and gradually increasing it can help minimise discomfort.
Serious Side Effects and When to Seek Help
Although rare, some users may experience more serious side effects. It’s important to be aware of these and seek medical attention if you notice:Signs of pancreatitis (persistent severe abdominal pain, nausea, vomiting)
Signs of thyroid issues (lump in the neck, hoarseness, difficulty swallowing)
Allergic reactions (rash, itching, swelling, trouble breathing)
Severe gastrointestinal symptoms that don’t improve
Always consult with a GP or your prescribing clinician if you have concerns while taking Mounjaro.
Comparing Mounjaro to Other Weight Loss Medications
Compared to other GLP-1 medications such as Wegovy or Ozempic, Mounjaro may offer enhanced results due to its dual-action approach. In clinical trials, tirzepatide has shown greater average weight loss than semaglutide — with patients achieving up to 22.5% weight reduction at higher doses.However, it’s important to remember that effectiveness can vary from person to person, and what works best depends on your medical history, goals, and access to treatment options.
Is Mounjaro Available in New Zealand?
As of now, Mounjaro is not available for prescription in New Zealand. Regulatory approval is still pending, and it may take some time before it becomes available through the public or private system.In the meantime, Pocket Lab offers a Weight Loss Care Plan featuring another clinically proven GLP-1 medication — Wegovy — which is available via prescription through an online consult.
Our virtual GP team will assess your needs and provide ongoing support throughout your weight loss journey.
Mounjaro isn’t available right now, but Wegovy is another alternative that is available. Take our free weight loss program eligibility quiz and find out if it’s right for you.
