From celebrity red carpets to GP clinics, Mounjaro is everywhere. With its promise of significant appetite suppression and weight reduction, this once-weekly injection is fast becoming a popular treatment for obesity. But as with any medication, understanding the full picture is key, including the side effects, how long they last, and what could happen if you stop. HELLO! explores Mounjaro side effects and what to expect when you come off the drug, based on the latest clinical guidance and firsthand insights from leading doctors and pharmacists.
What is Mounjaro?
Mounjaro is the brand name for tirzepatide, a dual GLP-1/GIP receptor agonist that mimics two naturally occurring hormones in the body. Dr Angela Kwong, a GP with a special interest in obesity management, explains: "Mounjaro is approved in Australia for the treatment of type 2 diabetes, weight management in adults with obesity, or those with weight-related health conditions, and most recently, obstructive sleep apnoea in adults with obesity." Leading Pharmacist Jason Murphy, adds: "The active ingredient, tirzepatide, targets both GLP-1 and GIP receptors. That dual mechanism makes Mounjaro different from many other weight loss injections and helps deliver stronger appetite control and more effective weight loss results when used alongside diet and exercise."
© Getty ImagesCommon side effects
So what are the side effects of Mounjaro? According to Dr Kwong: "The most common side effects are gastrointestinal, nausea, vomiting, constipation, bloating, diarrhoea, and a reduced appetite. These tend to be mild and improve over time as your body adjusts to the medication." Jason agrees, noting that: "around one in ten people experience these side effects, mostly when they first start the treatment or when their dose increases. The good news is that these reactions are usually short-lived and can be managed with simple lifestyle adjustments."
© Getty ImagesStaying hydrated, eating smaller meals, and avoiding greasy, spicy or overly rich foods can help reduce discomfort. Regular light movement can also ease symptoms. Dr Kwong stresses the importance of not under-eating when appetite drops, saying: "A common mistake people make is to eat too little when they’re not feeling hungry. Running on empty can make nausea worse and leave you feeling drained." Jaosn adds: "If nausea lasts more than a few days, or if diarrhoea persists for over a week or includes blood, you should check in with your GP."
When do Mounjaro side effects typically subside?
One of the most common questions people have is how long the side effects of Mounjaro last. According to the experts, the adjustment period varies between individuals, but most symptoms ease once a 'steady state' is reached. "Side effects are usually most noticeable when the dose is increased," says Dr Kwong. "Following the prescribed escalation schedule carefully and checking in with your doctor is the best way to minimise discomfort." Jason confirms this, saying: "In most cases, side effects subside as your body gets used to the medication, so you shouldn’t have to worry too much. Most people find symptoms like nausea fade within a few days."
© Getty ImagesCan you just stop taking Mounjaro?
So what happens if you decide to stop taking Mounjaro? "The consumer medicine information clearly advises against stopping suddenly without medical advice," says Dr Kwong. "You need to work with your doctor on a plan that takes into account how long you've been on the medication and what your goals are. That might include tapering off slowly or transitioning to another support strategy."
Jason adds: "Before stopping Mounjaro, always speak with your GP or pharmacist. They may recommend a step-down approach, gradually reducing your dose over a few weeks to ease the transition and prevent a sudden return of symptoms." He explains that some people experience a return of appetite and cravings after stopping, especially if lifestyle habits haven’t been locked in."
That's why it's so important to use Mounjaro as part of a broader plan. If you’ve built strong routines with food and exercise, you’re much better placed to maintain your weight loss results."What happens after stopping Mounjaro? So what does life after Mounjaro really look like? Dr Kwong says the experience is different for everyone. "Some patients maintain their new weight and habits with ease. Others find old cravings creeping back in. It’s not a failure, it’s your body recalibrating. That’s why having a plan in place is essential."
Jason adds that education is key. "Understanding how the medication works, how your appetite may change, and when to seek support gives people the best chance of long-term success." As for long-term Mounjaro side effects, the research is still developing. Serious risks like pancreatitis or gallbladder issues are rare but can occur. Monitoring and regular reviews are essential. Meanwhile, ongoing studies continue to explore any possible links to other conditions. Dr Kwong adds: "We’re learning more every day, but for now, the focus remains on using the medicine safely and effectively, with medical oversight and lifestyle support at the core."
Expert bios
- Dr. Angela Kwong, MBBS DCH FRACGP is a Sydney-based GP and the NSW State Lead for the RACGP Specific Interests Group in Obesity Management. She is the Founder of Enlighten Me, an award-winning medically supervised weight management program and doctor designed meal replacement shake.
- Jason Murphy is the Head Pharmacist of Chemist4U. He graduated from Queen's University Belfast in 2007 and became a dedicated member of the Pharmaceutical Society of Northern Ireland. He focuses on weight management, combining clinical expertise with a passion for accessible healthcare.
