Does Mounjaro cause heart palpitations?

Feeling your heart race, flutter or pound can be unsettling, especially if you've recently started Mounjaro. According to the patient information leaflet, a fast pulse is a common side effect when the treatment is used for type 2 diabetes, but otherwise uncommon when used for weight management. Even so, heart palpitations may happen for many different reasons that aren’t linked to the medication itself.

In many cases, palpitations are temporary and not caused by a serious underlying problem. They may be triggered by factors such as dehydration, stress, caffeine, changes in blood sugar levels, or an increase in physical activity. However, any new, persistent or worsening symptoms should be discussed with a healthcare professional rather than being assumed to be a normal side effect.

In this guide, we'll explore whether Mounjaro can cause heart palpitations, what the evidence says about changes in heart rate, other possible causes, how to manage symptoms, and when it's important to seek medical advice.

What's the difference between heart palpitations and a fast heart rate?

Mounjaro can make your heart beat faster, but an increased heart rate isn’t quite the same as palpitations. A fast pulse is a recognised side effect of Mounjaro, while palpitations are not listed separately in the patient leaflet.

According to the British Heart Foundation , palpitations are the sensation of becoming aware of your heartbeat or noticing a change from its usual rhythm. People describe them as:

• a fluttering feeling in the chest
• the heart racing or pounding
• skipped or extra beats

In other words, a faster heart rate is something that can be measured, while palpitations are something you feel. And palpitations can have many causes that have nothing to do with your medication. So, palpitations on Mounjaro do not necessarily mean Mounjaro is the cause.

The British Heart Foundation explains that most people experience palpitations at some point in their lives and, in many cases, they are not caused by a serious heart condition. Even so, it’s a good idea to speak to a healthcare professional about any new, persistent, or worrying symptoms.

How does Mounjaro affect your heart rate?

Mounjaro can cause a small increase in heart rate for some people.

The official product information gives more detail from clinical trials:

• in studies of people with type 2 diabetes, the biggest average rise in heart rate was 3-5 beats per minute
• in a weight management study of people without type 2 diabetes, 2.4%, 4.9%, and 6.3% of people taking the 5 milligram (mg), 10mg, and 15mg doses had a rise in heart rate of more than 20 beats per minute at two or more visits in a row, compared with 1.2% of people taking a placebo (a dummy treatment)

So, most people in these studies experienced only a small increase in heart rate. Larger increases were uncommon but happened more often at higher doses.

Why am I experiencing heart palpitations on Mounjaro?

Experiencing palpitations while taking Mounjaro doesn’t automatically mean Mounjaro caused them. There are lots of other common triggers, and some are linked to the changes that can come with treatment, rather than the treatment itself.

Dehydration

Dehydration on Mounjaro is common in people who suffer with certain common side effects like vomiting, nausea, or diarrhoea, which can all cause loss of fluids. The NHS lists a fast heartbeat as a sign of dehydration, so be mindful of that.

Low blood sugar

If you take Mounjaro alongside a sulphonylurea or insulin for type 2 diabetes, low blood sugar (hypoglycaemia) is very common. The leaflet lists a fast heartbeat among the warning signs, along with sweating, dizziness, feeling hungry, and confusion.

Caffeine, alcohol, and nicotine

The British Heart Foundation lists smoking, caffeine, alcohol, stress and lack of sleep among the common triggers for palpitations. Due to its effects on appetite, Mounjaro can make you tired as you eat less throughout the day. So, if you’ve started relying on extra coffee or energy drinks to get through the day, this could be playing a part.

Exercise and increased physical activity

Strenuous physical activity is another common trigger. If you’ve recently started exercising more as part of your weight loss journey, you may notice your heartbeat more than before.

Stress, anxiety, and excitement

Strong emotions like anxiety, excitement, and stress can all bring on palpitations. Starting a new treatment or making big lifestyle changes can be stressful in itself.

Hormonal changes

Hormonal changes during periods, pregnancy, or menopause can cause palpitations, according to the BHF.

Other health conditions and medicines

Some health conditions, such as an overactive thyroid or anaemia, can also cause palpitations. So can some medicines, including certain asthma inhalers and cold and cough remedies. Your GP can check for those if needed.

How to manage heart palpitations while taking Mounjaro

In many cases, a few simple changes can help you feel calmer and more in control. Often the easiest fix isn't to stop treatment, but to avoid the potential triggers.

Stay hydrated

The Mounjaro patient leaflet advises drinking plenty of fluids to avoid dehydration, especially if you’re dealing with sickness or diarrhoea. Keeping a water bottle with you through the day is an easy habit to build. Our guide to the benefits of drinking water has more ideas for you.

Reduce caffeine intake

The British Heart Foundation lists smoking, caffeine, alcohol, stress and lack of sleep among the common triggers for palpitations.

Limit alcohol

Alcohol is also a common trigger for palpitations, and drinking too much can also lead to dehydration. If you notice palpitations after drinking, it may be worth cutting back. For more information, check out our guide to whether you can drink alcohol on Mounjaro.

Find ways to manage stress

The NHS recommends stress-management techniques such as mindfulness, breathing exercises, physical activity and relaxation techniques to help manage anxiety and stress. Just a 50-10 minutes a day can be a good place to start. This is important as stress can also lead to emotional eating, which impact your progress on the medication.

Monitor your blood sugar

If you have type 2 diabetes and take insulin or a sulphonylurea and feel your heart racing, it’s worth checking your blood sugar. Your doctor should tell you how to treat low blood sugar if it happens.

Do heart palpitations go away on Mounjaro?

For many people, yes. Whether palpitations settle depends on their cause. Some episodes resolve on their own, while others may need medical assessment or treatment. If they persist, recur or worsen, contact your healthcare professional for assessment.

Palpitations can last anywhere from a few seconds to a few days. It’s also worth knowing that Mounjaro’s digestive side effects, like nausea and diarrhoea, are most common when you first start treatment and ease over time for most people. As these settle, the risk of dehydration-related palpitations may ease too.

If your palpitations don’t settle, or they’re affecting your everyday life, speak to our clinicians. They can review your treatment and may suggest a lower dose or a check-up with your GP.

“Palpitations can feel worrying, but if they're linked to factors such as dehydration or gastrointestinal side effects while taking Mounjaro, they may improve as these symptoms settle. If they keep happening or are affecting your day-to-day life, please speak to your clinical team. We can review how you’re getting on and may recommend adjusting your dose or speaking to your GP for further checks.”

Niya MansuriPrescribing Pharmacist

When should you seek medical advice for heart palpitations?

Most palpitations are not a sign of anything serious, but some symptoms do need checking.The NHS recommends seeking medical advice if palpitations are becoming more frequent, lasting longer than usual, or are accompanied by symptoms such as dizziness, fainting, chest pain or shortness of breath.

Get medical help immediately if a fast heartbeat comes with breathing problems or swelling of your lips, tongue, or throat. The Mounjaro patient leaflet lists these as possible signs of a severe allergic reaction, which is rare.

Call 999 or attend your nearest A&E department if a rapid heartbeat occurs alongside severe symptoms such as difficulty breathing, chest pain, confusion, severe dizziness, or signs of a serious allergic reaction.

If you're concerned about persistent palpitations, contact your GP, NHS 111, or your prescribing healthcare professional for advice.

Support for Mounjaro side effects

Noticing your heart racing can be worrying, but you don’t have to work out what’s going on by yourself.

If you’re a myBMI patient, your treatment plan includes ongoing clinical support with side effects. If you have questions about palpitations or any other side effect, our clinical team are here to help you find a way forward that works for you.

Sources

• Heart palpitations. (2026) NHS. [Accessed October 2026]
• Dehydration. (2026) NHS. [Accessed October 2026]
• Heart palpitations. (2025) British Heart Foundation. [Accessed October 2026]
• Breathing exercises for stress. (2026) NHS. [Accessed October 2026]
• Mounjaro (tirzepatide) Summary of Product Characteristics. (2026) electronic Medicines Compendium (emc). [Accessed October 2026]