Why Does Mounjaro Increase Heart Rate?

Mounjaro is a dual GIP and GLP-1 receptor agonist — meaning it activates two appetite-regulating pathways simultaneously. GLP-1 receptors are found not only in the gut and brain but also in cardiac tissue, and stimulating them can produce a modest increase in heart rate. This is a known, documented effect seen across the GLP-1 receptor agonist class of medicines.

How much of an increase is commonly reported?

Many people describe an elevation of around 5–15 beats per minute above their usual baseline, though individual responses vary considerably. This effect is generally most noticeable in the early weeks of starting Mounjaro or after moving to a higher dose, and it often settles as the body adjusts. According to information published on the electronic Medicines Compendium (eMC), increased heart rate is listed among the recognised effects associated with tirzepatide.

Heart rate, exercise, and weight loss

Separately from Mounjaro's direct effect, many people on a weight-loss journey also become more active, which naturally raises average daily heart rate. Understanding your target heart rate for weight loss — sometimes described as the optimal heart rate zone for fat-burning exercise, typically framed as a moderate-intensity range — can help you interpret the numbers you are seeing. However, what counts as an ideal heart rate range for weight loss during exercise is very different from a persistent elevated resting heart rate, and it is important not to confuse the two.

If you are curious about how your metabolism and energy expenditure fit into your journey, understanding your basal metabolic rate can provide useful context alongside any heart rate data you are tracking, and you can explore how to calculate your basal metabolic rate to see how these figures relate to each other.

For a broader look at how tirzepatide works in the body, the complete guide to how Mounjaro works covers its mechanisms in detail. It is also worth noting that a similar effect has been observed with other GLP-1 medicines — if you are interested, you can read about whether Wegovy increases heart rate in the same way.

One of the most practical things you can do when you notice a change like an elevated heart rate is to log it consistently, so you have an accurate picture to bring to your prescriber rather than relying on memory. GLP Trackr's side-effect and symptom tracker lets you record how you feel day by day — including energy levels, heart palpitations, or any cardiovascular sensations you want to monitor — and surfaces patterns over time that can make your prescriber conversations far more productive.

Alongside symptom logging, the daily morning check-in captures mood, energy, and sleep in under a minute, giving you a running record of how your body is responding at different stages of your journey. If your heart rate changes coincide with a dose adjustment or a shift in your exercise habits, that context is right there in your log.

Ready to start building a clear record of your journey? Download GLP Trackr on the App Store or Google Play — your first seven days are completely free.

Important: if you experience a rapid, very high, or irregular heart rate, chest discomfort, shortness of breath, or any symptom that feels severe or worrying, contact your healthcare professional promptly — do not wait for your next scheduled appointment. GLP Trackr is a tracking tool that helps you record and communicate what you are experiencing; it is not a substitute for clinical assessment. Any decisions about your medication should always be made with your prescriber, never on your own.