Palpitations on Mounjaro: What They Are and When to Seek Help

A small number of people taking GLP-1 or dual GIP/GLP-1 receptor agonists like tirzepatide report noticing changes in their heart rhythm or a heightened awareness of their heartbeat. There are a few reasons this may happen:

• Heart-rate changes: GLP-1 receptor agonists are known to produce a modest increase in resting heart rate in some people. This is a recognised pharmacological effect and is reflected in the medicine's official product information.
• Dehydration: Gastrointestinal side effects such as nausea, vomiting, or diarrhoea — which are commonly reported, particularly in the early weeks — can lead to fluid loss. Dehydration is a well-known contributor to palpitations in general.
• Reduced calorie intake: Many people find their appetite decreases significantly on Mounjaro. A substantial drop in food or electrolyte intake can sometimes affect heart rhythm awareness.
• Anxiety or heightened body awareness: Starting a new medication often brings increased attention to bodily sensations, and some people find they notice their heartbeat more than usual.

It is important to note that palpitations can also have causes entirely unrelated to Mounjaro — including caffeine, stress, poor sleep, or underlying cardiac conditions. None of this content constitutes a diagnosis, and a healthcare professional is the right person to help you identify the cause in your specific situation.

For a more detailed look at how heart palpitations relate to this medicine, see our dedicated page on heart palpitations and Mounjaro, and if you are new to the medication, the broader guide to being on Mounjaro covers many of the commonly reported experiences people have in the early weeks.

When palpitations occur, keeping a clear log of when they happen, how long they last, what you were doing, and any accompanying symptoms gives you — and your prescriber — genuinely useful information. Vague recollections are much harder to act on than a timestamped record.

GLP Trackr's side-effect tracker lets you log palpitations (and other symptoms) with a note and timestamp each time they occur, so a pattern — if one exists — becomes visible over time. That record can be shared directly with your prescriber at your next appointment, giving them a clear picture rather than a rough estimate. Alongside side-effect logging, the app's daily check-in captures water intake and energy levels, which can help you spot whether dehydration or fatigue correlates with episodes. If you want to bring a summary to a clinical appointment, the doctor report feature pulls your logged data together in a readable format.

Some general self-care steps that many people on GLP-1 medicines find helpful — staying well hydrated, eating regular small meals with adequate protein, and limiting caffeine — are worth discussing with your prescriber or doctor as part of managing your overall wellbeing on the medication.

Always follow the guidance of your prescriber or doctor — they know your full medical history and are best placed to assess whether palpitations need investigation. If you experience palpitations that are severe, prolonged, happen alongside chest pain or shortness of breath, or simply feel wrong to you, seek medical attention promptly rather than waiting. Any concerns about your medication should be raised with your healthcare professional; if you believe you have experienced a side effect, you can also report it through your national reporting scheme (such as the UK's Yellow Card scheme).

You can find broader information on the Mounjaro journey, including other commonly reported side effects, on our Mounjaro overview hub.

Ready to start logging how you feel? GLP Trackr is free to try for 7 days — download it on the App Store or Google Play and keep a clear record of your symptoms to discuss with your prescriber.