Can Weight Loss Injections Cause Kidney Stones?

GLP-1 receptor agonists like semaglutide and tirzepatide work by acting on appetite-regulating pathways, slowing gastric emptying, and reducing food noise. Their most commonly reported side effects are gastrointestinal — nausea, constipation, diarrhoea — rather than kidney-related. According to the electronic Medicines Compendium (eMC) product information for both Mounjaro and Wegovy, kidney stones do not appear in the listed common adverse effects.

Why the question comes up

There are a few reasons people make the connection. Reduced appetite can sometimes mean drinking less fluid, and lower fluid intake is a well-known risk factor for kidney stones regardless of any medication. Significant dietary changes — eating less, shifting food choices — can also alter the balance of minerals processed by the kidneys. None of this is specific to GLP-1 medicines, but it is worth being aware of if you are already prone to kidney stones or have been advised to maintain high fluid intake.

When to seek advice

If you experience flank pain, blood in urine, or pain on urination while taking Mounjaro or Wegovy, contact your healthcare professional promptly rather than assuming it is a known side effect of your medication. These symptoms need proper assessment. Any unusual or persistent symptom that concerns you should always be discussed with your prescriber or doctor — they know your full medical history and can advise accordingly.

It is also worth noting that questions about less common or serious symptoms are different in nature from the topic of cancer risk, which some people also ask about. For broader questions along those lines, you may find it useful to read about whether weight loss injections can cause cancer or explore what is currently known about weight loss injections and cancer risk. Both pages cover a separate and distinct topic, but the same principle applies: factual, neutral information alongside clear guidance to speak to your prescriber.

If you ever notice a side effect you are unsure about, consider reporting it through your national pharmacovigilance scheme — such as the UK's Yellow Card scheme — as well as telling your healthcare team.

One of the most practical things you can do if you have any concern about kidney stones — or any other ongoing symptom — is keep a clear record over time. GLP Trackr's side-effect tracker lets you log how you feel day to day, so that if something recurs or worsens, you have a timeline to bring to your prescriber rather than trying to recall details from memory.

Hydration is another area where the app can help. Because reduced appetite on GLP-1 medicines can mean it is easy to forget fluids as well as food, GLP Trackr includes a daily water target and check-in so you can make sure you are hitting a reasonable intake consistently — something that matters for general kidney health regardless of medication. You can also use the daily morning check-in to note energy levels and wellbeing, building a fuller picture of how you are doing week to week.

The weight loss injections guide covers a broader range of topics relevant to your journey, from managing common side effects to understanding how these medicines work.

GLP Trackr is a tracking and journaling tool — it is not a substitute for your prescriber's advice, and nothing logged in the app replaces a clinical assessment. If symptoms are severe, persistent, or worrying, contact your healthcare professional promptly.

Start logging your symptoms and daily hydration — GLP Trackr is free to try for 7 days on the App Store and Google Play.