People who stop using Mounjaro regain weight and reverse other health benefits, study shows

Experts found greater weight regain after withdrawal of Mounjaro was associated with greater reversal of improvements not only in weight, but also in measures including waist circumference, levels of 'bad' cholesterol, blood pressure, and blood glucose levels. Picture: Niall Carson/PA Wire

People who stop using the weight-loss jab Mounjaro not only tend to regain weight but also experience a reversal of other health improvements, research suggests.

Mounjaro, which contains the active ingredient tirzepatide, has become a popular weight-loss medication, with studies suggesting it can help people lose an average of 20% of their body weight after 72 weeks of treatment.

However, research has previously found people who stop using tirzepatide tend to regain much of the weight they have lost.

Now experts studying results from a clinical trial known as Surmount-4 say other benefits seen with the medication, such as reduced blood pressure and lower levels of “bad” cholesterol, also go into reverse upon stopping the jabs.

Writing in the journal Jama Internal Medicine, the team of researchers — which included experts from the pharmaceutical company that makes Mounjaro, Eli Lilly — report how the Surmount-4 trial involved participants with obesity or who were overweight and had at least one weight-related health problem.

All participants received tirzepatide for 36 weeks, alongside diet and exercise support, before being randomly split into two equal-sized groups, one of which continued the medication for a further 52 weeks, while the other switched to a placebo for this period. Both participants and researchers were unaware at the time as to who was in which group.

The team focused on results from 308 participants who had lost at least 10% of their body weight by the end of the initial 36-week period before switching to the placebo, finding one year after stopping tirzepatide, 82% of these participants had regained 25% or more of their initial weight reduction.

The team found greater weight regain at the end of the study was associated with greater reversal of improvements not only in weight, but also in measures including waist circumference, levels of “bad” cholesterol, blood pressure, and blood glucose levels.

“Overall, at week 88, participants with 75% or more weight regain after tirzepatide withdrawal reversed cardiometabolic parameters to baseline (week 0) values,” the team wrote, although they note those with up to 50% weight regain still showed improvements in these areas compared with the start of the study.

Another piece of research suggests women who stop using weight-loss medications such as tirzepatide or semaglutide before becoming pregnant or early in pregnancy tend to gain more weight while pregnant and have a higher risk of preterm delivery, gestational diabetes, and hypertensive disorders of pregnancy than those who had not used such drugs.

The Guardian