What the studies show
In SURMOUNT-4, all participants first took tirzepatide for 36 weeks and lost about 21% of their weight on average. Then half were switched to placebo: over the following year they regained around 14% on average, while the group staying on tirzepatide kept losing weight. More than 80% of those who stopped regained at least a quarter of the weight they had lost – and blood pressure and blood sugar got worse along with it.
For semaglutide, the extension of the STEP-1 study showed a similar picture: one year after stopping, about two thirds of the lost weight had come back on average.
Why does this happen?
Obesity is a chronic disease with strong biological counter-regulation: hunger hormones rise and energy expenditure falls. GLP-1 medications dampen these signals – but only while they are working. That is not personal failure, it is biology.
How to prepare
- Always plan stopping or reducing with your doctor – don’t stop abruptly on your own
- Lock in habits while the injection is still helping: protein-rich eating, portion sizes, regular meals
- Make strength training a habit – more muscle mass makes maintaining your weight easier
- Keep tracking your weight and waist after stopping and react early
- Look for support: nutritional counselling, exercise – and talking with others going through the same thing
When to see a doctor
- You want to stop or reduce the dose
- After stopping, your weight, blood pressure or blood sugar rise significantly
- You take the medication for diabetes – then never stop without talking to your doctor
In an emergency: 112.
FAQ
Do you regain weight after stopping Mounjaro?
Most people do. In the SURMOUNT-4 study, participants regained around 14% of their weight on average after switching to placebo.
Can you taper off the weight-loss injection?
There is little study data on this so far. Whether and how you reduce should be planned with your doctor.
Do I have to take the weight-loss injection for life?
That varies from person to person. Studies show that the effect usually fades without the medication. The decision belongs in your doctor’s hands.
Sources
This article does not replace medical advice. It gives no dosing recommendations. As of September 2026.