Mounjaro and Kidney Stones: Can It Cause Them? (October 2026)

01 · The core answer

Can Mounjaro cause kidney stones?

There is no established direct link between Mounjaro and kidney stones. Kidney stones do not appear as a listed side effect in the product information, and the medicine is not known to damage the kidneys or liver directly.¹¹³

What the product information does flag is an indirect route. Severe vomiting or diarrhoea can cause dehydration, which can strain the kidneys, so you should keep fluids up and get medical help straight away if you cannot keep fluids down.¹ But dehydration is the thing worth guarding against, and it is within your control.

If you want the wider picture, our guides on whether kidney stones are a side effect and whether Mounjaro can cause kidney issues go into related questions.

02 · Your decision

Can you take Mounjaro if you have kidney stones?

Having had a kidney stone does not appear in the list of reasons not to take Mounjaro, but your prescriber needs to know about it. The documented reasons for caution are an allergy to tirzepatide or its ingredients, pregnancy or trying to conceive, and a history of pancreatitis, severe gut or digestive disease, diabetic retinopathy or gallbladder problems.¹ Mounjaro must not be used during pregnancy, and it 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.

In practice, a prescriber will want to know whether your stones were recent, whether you have been advised to restrict anything, whether you have any ongoing kidney problem, and what else you take. People with severe kidney impairment need individual prescriber assessment, while no dose adjustment is needed for mild to moderate kidney impairment.¹

Our fuller answer is in can I take Mounjaro if I have kidney stones.

03 · What to do next

What should you do next?

What you do depends on which of three situations you are in. Use this table as a quick guide, and treat it as signposting rather than a diagnosis.

For broader reading on how the whole group of weight-loss injections is viewed, see can weight loss injections cause kidney stones.

04 · What the label says

What the product information says about kidneys

The product information describes Mounjaro as not known to damage kidneys or liver directly, with no dose adjustment needed for mild to moderate kidney or liver impairment.¹ It then names the practical risk: severe vomiting or diarrhoea can cause dehydration, which can strain the kidneys.¹³

Kidney stones are not on the list of side effects in the UK Mounjaro patient leaflet. That means they are not a listed side effect, not that a link is impossible, so tell your prescriber about any new or lasting symptom.

A stone can occur in anyone, including people who take no medicine at all. Starting a new treatment around the same time as developing a stone makes the two look connected, but timing alone does not show cause. Anyone who suspects a link should tell their prescriber and can report it through the Yellow Card scheme, which is how regulators detect patterns that individual cases cannot show.¹⁹

05 · The dehydration pathway

The dehydration pathway explained

Dehydration is the realistic concern on Mounjaro, and it has a clear route. The medicine slows how quickly the stomach empties and helps you feel fuller sooner, which many people welcome.¹ Some people also drink less than usual because they feel full, nauseous or simply less inclined to think about food and drink at all.

Add vomiting or diarrhoea, which are among the digestive effects people may notice while their body adjusts, and fluid loss can outpace intake. The product information is explicit that this can strain the kidneys, and it tells you to keep fluids up and get medical help straight away if you cannot keep fluids down.¹

Dehydration is also most likely to bite at certain moments: dose increases, a stomach bug, hot weather, or a busy day when meals and drinks get skipped. Planning for those moments is more useful than worrying in general.

06 · Weight loss and stones

Weighing a stone history against the benefits

Whether weight loss changes stone risk is a legitimate question to raise with your prescriber, particularly if you have a history of stones.

It also helps to keep the benefit side in view. 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, and individual results vary.

Weight management is also linked to wider health changes. In trials, weight loss on tirzepatide came with average improvements in waist size, blood pressure, cholesterol and blood-sugar measures.¹ These are trial-average secondary outcomes, not promises, but they are why prescribers talk about weight management as health management rather than appearance.

The sensible reading is balance. A past stone is something to disclose and plan around, not necessarily a reason to rule out treatment. That decision belongs to you and your prescriber, with the full history in front of you both.

07 · Other injections and stones

Do other weight-loss injections cause kidney stones?

This question comes up for every medicine in the class, including semaglutide (Wegovy). Tirzepatide acts on two gut-hormone receptors, GIP and GLP-1, while semaglutide acts on one, but both slow stomach emptying.¹

So the practical advice overlaps. Keep fluids up, take vomiting and diarrhoea seriously, and tell your prescriber about any history of stones before you start. If you use a different medicine, speak to your prescriber or pharmacist about any new symptom.

For wider reading, our pages on whether weight loss drugs cause kidney stones and on how this medicine class relates to kidney stones cover the topic from other angles. If you are weighing medicines against each other, the Wegovy pen page shows what is available, and your prescriber can discuss which suits you.

08 · Warning signs and help

Warning signs: when to get help

Get medical help straight away if you have severe pain, if you cannot keep fluids down, or if anything feels seriously wrong. Pain from a stone, from the gallbladder and from the pancreas can all be severe and can feel alike, which is exactly why it needs assessing.

Some serious side effects of Mounjaro need urgent attention whatever you suspect. Seek immediate medical help for severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis), or for pain in the upper right abdomen, fever or yellowing of skin or eyes (possible gallbladder problems).¹ Signs of a severe allergic reaction, such as swelling of the face or throat and difficulty breathing, also need immediate medical help.

If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion), because your prescriber may need to adjust those medicines.¹

Do not wait for a scheduled review if you are unwell. Contact your clinical team, or get medical help straight away through the NHS urgent advice service or emergency services where pain is severe. Tell whoever treats you that you use Mounjaro, so they can factor it in.

09 · Staying hydrated on treatment

Practical ways to keep fluids up

The most useful thing you can do is make drinking a habit rather than a decision. Because the medicine can dull appetite and slow stomach emptying, thirst cues are easy to ignore. Small, regular drinks through the day work better than trying to catch up in the evening.

• Keep a bottle where you work, drive or relax, and refill it as a routine.
• Drink alongside meals and between them, in small amounts if you feel full quickly.
• Plan extra fluid for hot weather, exercise, travel and any day you feel unwell.
• After a dose increase, pay particular attention for the first few days, when digestive effects are most likely to be noticed.
• If you are vomiting or have diarrhoea, sip frequently and get medical help straight away if you cannot keep fluids down.

If a doctor has given you specific fluid or diet advice because of past stones, follow that advice.

Our ongoing monthly reviews, dose-titration and follow-up assessments by the prescribing team include side-effect support, so you can raise hydration, nausea or any new symptom at each check-in rather than carrying on alone.

10 · Starting treatment safely

Starting Mounjaro if you have a stone history

Starting treatment with a stone history is a conversation, not a form field. Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber, and used alongside a reduced-calorie diet and increased physical activity.

• Free online consultation. A short health questionnaire, no charge, no obligation. Include your stone history and any medicines you take.
• Prescriber review. Your answers are reviewed by a GPhC-registered prescriber, not a scoring script. Payment is taken when you place the order; if the prescriber decides the treatment is not suitable, the order is refunded automatically in full.
• Dispensing and dispatch. Dispensed by our registered pharmacy, with same-day dispatch when ordered by 3pm.
• Delivery. Free next-day tracked delivery in temperature-controlled, discreet packaging. Saturday delivery is £14.99.

Our Mounjaro comes through official LillyDirect supply, and repeat orders re-check suitability, with no auto-shipping, so a change in your health can be picked up. You can see how it all fits together on our weight loss clinic page.

11 · Reporting and further reading

Reporting a symptom and what happens next

If you think Mounjaro may have caused a symptom, you can report it yourself through the MHRA Yellow Card scheme.¹⁹ You do not need to be certain of the cause. Reports from patients and clinicians help regulators identify patterns that a single case cannot show, and the scheme also covers counterfeit medicine concerns.⁷

Report in addition to, not instead of, speaking with your prescriber. They can look at the whole picture, including your dose, your other medicines, your fluid intake and any digestive effects, and decide whether anything should change.

If you stop treatment, 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.¹ That is worth knowing if you are deciding whether to pause while a symptom is investigated: talk it through with your prescriber first.

Mounjaro (tirzepatide) is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. Individual results vary. This page is information, not a substitute for medical advice.