Short answer: Slightly, on average. In the label trials, resting heart rate rose by about 2 to 3 beats per minute on Ozempic, 1 to 4 on Wegovy, 2 to 4 on Mounjaro and 1 to 3 on Zepbound, compared with placebo. Wegovy carries a warning: some people had larger jumps, and the label says to check heart rate regularly and stop Wegovy if resting heart rate stays up. Its leaflet says to report a racing or pounding heart that lasts several minutes.
| Medicine and trials | On the medicine | Placebo |
|---|---|---|
| Ozempic 0.5 mg and 1 mg, type 2 diabetes | Up 2 to 3 beats per minute | Down 0.3 |
| Wegovy, adults, weight reduction | Up 1 to 4 beats per minute more than placebo | n/a |
| Mounjaro, type 2 diabetes | Up 2 to 4 beats per minute | Up 1 |
| Zepbound, weight reduction | Up 1 to 3 beats per minute | No increase |
These are averages across thousands of people. Averages hide the spread, which is what the Wegovy and Mounjaro labels describe next.
The Wegovy label reports the largest change from baseline each person had at any visit. In the adult weight-reduction trials, more people on Wegovy than on placebo had a peak rise of 10 to 19 beats per minute (41% versus 34%) and of 20 or more (26% versus 16%). In the trial of people aged 12 and older with a normal starting heart rate, 54% on Wegovy versus 39% on placebo had a peak rise of 20 or more.
The Mounjaro label reports episodes of a fast regular heartbeat (sinus tachycardia) with a rise of 15 or more beats per minute in 4.6%, 5.9% and 10% of people on 5, 10 and 15 mg, against 4.3% on placebo. Among people enrolled in Japan the figures were higher, up to 23% on 15 mg. The label says the clinical relevance of these heart rate increases is uncertain.
Wegovy is the only one of the four with heart rate increase in its Warnings and Precautions section. It tells prescribers to monitor heart rate at regular intervals consistent with usual practice, to ask patients to report palpitations or a racing heartbeat at rest, and to stop Wegovy if a patient has a sustained increase in resting heart rate.
The Wegovy leaflet puts it this way: tell your healthcare provider if you feel your heart racing or pounding in your chest and it lasts for several minutes. It also says your provider should check your heart rate while you take Wegovy.
The bigger picture on the heart is different from the heart rate numbers. Wegovy is FDA approved to lower the risk of heart attack, stroke and heart-related death in adults with established heart disease and obesity or overweight. In Mounjaro's heart outcomes trial against dulaglutide (another GLP-1 medicine), major heart events happened to 12.1% on Mounjaro and 13.0% on dulaglutide, meeting the goal of not being worse.
The leaflets list a fast heartbeat among the signs of low blood sugar, which is more likely with insulin or a sulfonylurea (see low blood sugar on GLP-1 medicines). The Mounjaro and Zepbound leaflets list a very rapid heartbeat among signs of a serious allergic reaction, alongside face or throat swelling and trouble breathing, and say to get medical help right away.
If you have a watch or cuff that measures resting heart rate, a few readings taken at the same time of day, logged with your dose dates, give your prescriber more to go on than a single reading in the clinic. Dose Track keeps those notes next to each dose.
Read more on Dose Track: GLP-1s, testosterone and blood pressure · Wegovy side effects · Ozempic side effects · Mounjaro side effects · Zepbound side effects