Long Term Effects of Mounjaro: What We Know (October 2026)

01 · The core answer

Are there long term effects of Mounjaro?

Yes, there are long term effects, and most are the intended ones: lower weight, and better blood pressure, cholesterol and blood-sugar measures while you keep taking it. In trials, weight loss on tirzepatide came with average improvements in waist size, blood pressure, cholesterol and blood-sugar measures, and most participants with prediabetes returned to normal blood-sugar levels.² These are trial-average secondary outcomes, not promises.

If you want a deeper look at related questions, see our guides on Mounjaro long-term side effects and whether it has long term effects.

02 · Your decision

What should you do with this information?

If you are deciding whether to start, weigh the known benefits against the known risks, and be realistic that this is a medicine many people take for a long time. If you are already taking it, keep your monthly reviews, report new symptoms and ask your prescriber what your stopping plan would look like before you need one.

If you are ready to explore treatment, the Mounjaro pen consultation is free and reviewed by a GPhC-registered prescriber.

03 · Benefits over time

Benefits seen with long-term use

The pivotal weight-loss trial gives the clearest picture of sustained benefit. In the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone.² These are trial averages — individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.²

Many people want to know how likely a meaningful result is. At 72 weeks, 85% of participants on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of their body weight.² Half of participants on 10mg and 57% on 15mg lost at least 20% of their body weight.²

Beyond the scales, trial participants saw average improvements in waist size, blood pressure, cholesterol and blood-sugar measures. That is why prescribers talk about weight management as health management rather than appearance. Our blog on the health risks of obesity explains what those measures protect against over the years.

04 · Long-term side effects

Do side effects last long term?

For most people, the digestive effects of tirzepatide are most noticeable around starting and after dose increases, then ease as the body adjusts. The most common, affecting more than 1 in 10 people, are nausea, diarrhoea, vomiting, constipation and abdominal discomfort, and for most people they ease within days to a few weeks as the body adjusts.¹³

This is why the dose ladder is gradual. If a new dose is hard to tolerate, prescribers can hold the current dose longer before stepping up — speak to your clinical team rather than pushing through severe symptoms.

Persistent symptoms deserve attention, not endurance. If nausea, constipation or stomach discomfort do not settle, or they return and stay, tell your clinical team. Our related guides cover whether Mounjaro can cause lasting effects and what to expect when taking it for a long time.

05 · Serious risks

Serious but uncommon risks to know about

Serious side effects are uncommon but need urgent attention.¹³ Seek immediate medical help for severe, persistent stomach pain that may spread to your back, with or without vomiting, which could be pancreatitis. Also seek immediate medical help for pain in the upper right abdomen, fever or yellowing of skin or eyes, which could be a gallbladder problem, or for swelling of the face or throat and difficulty breathing, which can signal a severe allergic reaction.¹³

Your prescriber will take extra care, or may recommend against treatment, if you have a history of pancreatitis, severe gut or digestive disease, diabetic retinopathy, or gallbladder problems.¹ It should not be used during pregnancy or while trying to conceive, and should be stopped at least one month before trying to conceive. If you become pregnant during treatment, stop the medicine and tell your prescriber promptly. Always share your full medical history and medicine list during consultation.

If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar such as shakiness, sweating and confusion. Your prescriber may need to adjust those medicines.¹³ Suspected side effects can be reported through the MHRA Yellow Card scheme, which is how rarer long-term signals are picked up.¹⁹

06 · Liver, kidneys, thyroid

Liver, kidneys and thyroid

Mounjaro is not known to damage kidneys or liver directly, and no dose adjustment is needed for mild to moderate kidney or liver impairment.¹ The practical risk is indirect: severe vomiting or diarrhoea can cause dehydration, which can strain the kidneys. Keep fluids up and get medical help straight away if you cannot keep fluids down — dehydration needs medical help straight away. People with severe impairment need individual prescriber assessment.

Yellowing of the skin or eyes, with upper right abdominal pain or fever, could be a gallbladder problem and needs medical help straight away.

On the thyroid: in rodent studies tirzepatide caused thyroid C-cell tumours. It is not known whether this applies to humans, and no increase has been shown in human trials.¹ As a precaution, tell your prescriber if you or a close relative have had medullary thyroid cancer or the inherited condition MEN 2. Routine thyroid monitoring is not required for most people.

You may see this called the "black box warning" online. That is US labelling terminology; for UK patients, the relevant step is to tell your prescriber if you or a close relative have had medullary thyroid cancer or MEN 2.

07 · Mood and mental health

Mood and mental health over time

Regulators have looked specifically at whether this class of medicine is linked to low mood or suicidal thoughts. The EMA's safety committee reviewed the evidence and concluded in 2024 that it does not support a causal link, and the MHRA keeps this under continuous review.¹⁷ If you have thoughts of harming yourself or ending your life, get help straight away.

If you have thoughts of harming yourself or ending your life, get help straight away. Call 999 or go to A&E if you are in immediate danger. In England you can call NHS 111 and choose the mental health option, any time. You can also call Samaritans free on 116 123, day or night. Tell your prescriber about any change in your mood while taking Mounjaro.

That said, any big change in weight, appetite and routine can affect how you feel. Tell your prescriber about any history of depression, and seek help promptly if your mood drops or you have distressing thoughts during treatment.

08 · Stopping Mounjaro

What happens when you stop?

Tirzepatide has a half-life of about five days, so after a final dose it takes roughly four to five weeks to clear the system. There is no way to speed this up, and nothing needs doing while it clears.²

Speak to your prescriber before stopping so you can agree a plan. In SURMOUNT-4, people who stopped tirzepatide after 36 weeks regained on average 14% of body weight over the following year, while those who continued treatment lost a further 5.5% on average. Stopping should always be planned with your prescriber, with diet and activity habits ready to carry the load. Our page on staying on Mounjaro long term goes further.

09 · What is still unknown

What is still unknown

Regulators and the manufacturer continue to collect real-world safety data, which is normal for newer medicines. Our guide on what we know about this drug class covers the wider picture, and our Wegovy long-term side effects page covers the older semaglutide option.

Supplements marketed as "natural Ozempic" or the "poor man's Ozempic", such as berberine, are low-cost supplements with no clinical oversight. They are not equivalent to licensed medicines, and nothing "mimics" them naturally. The dramatic weight-loss claims attached to them are not backed by the trial evidence behind prescription treatment.

Which is safer, Mounjaro or Ozempic? Ozempic is semaglutide licensed for type 2 diabetes; it is not a UK weight-loss medicine, and prescribing it privately for weight loss is off-label. The licensed weight-management options are Mounjaro and Wegovy, and the safer choice depends on your health history. That is a prescriber decision.

10 · NHS and private routes

Getting treatment with proper follow-up

Mounjaro is available on the NHS, but access is being phased in over several years.⁶ NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition, and the NHS primary-care rollout began in June 2025 with the highest-need groups first (initially BMI 40+ with four or more qualifying conditions).⁴ Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.

Whichever route you take, long-term safety depends on follow-up. With us, treatment is reviewed by a GPhC-registered prescriber (GPhC 9012878), with ongoing monthly reviews, dose-titration and side-effect support, and repeat orders re-check suitability with no auto-shipping. You can explore our weight loss clinic for the full picture.