I am asked this question by my patients all the time. The simple, unvarnished truth is that—in the absence of another medical or surgical intervention—people who quit injectables can expect to regain 100% of what they lost. It usually takes eighteen months or so.
I don’t blame people for being confused, because you can’t really get a straight answer by searching the internet. Overall, the information is vague and all over the place. Most sources (Good Morning America, for instance) suggest that you can expect to regain around two thirds of the lost weight. That’s the exact response I got when I asked Google’s AI assistant, “Do you regain weight when you stop Wegovy?” It said:
Yes, most people regain a significant portion of lost weight after stopping Wegovy. Studies show that within 12 to 18 months of stopping, patients often regain two-thirds or more of the weight lost, …
I have found Google’s answers to be spot-on for many medical questions, but here they didn’t get it quite right.[i] We shouldn’t be too hard on Google here, because their answer derived from sources that set them up for that error.[ii]
The confusion about the extent of regain comes from the fact that it takes eighteen months or more to happen. Relatively few of the thousands of published studies on injectable weight-loss meds did any follow-up at all after treatment was discontinued,[iii] but thirty-five randomized, placebo-controlled studies did. The problem is that none of them followed up beyond the one-year mark. Not one. Because weight regain usually takes eighteen months, the studies ended too soon to capture it. The authors of these studies dutifully reported what they saw, which, alas, reflected only part of the regain.
There are a lot of medical studies published, and it is impossible to dive deeply into all of them.[iv] What interested doctors (me included) often do to save time is read a summary of the study called “the abstract.” The abstract reports numerical results, but those results often leave out an important piece of the story. Such is the case here.
Without digging more deeply into these regain studies, you might miss the fact that the headline numbers tell an incomplete story. Deeper in the publication and its appendices, you find the detailed charts and graphical data that tell the real story. Graphical data from the weight regain trials show that regain was still going strong at one year. A visual abstract (I had never seen one of these before) from a recent meta-analysis in the British Medical Journal (BMJ) provides a pithy visual summary of the state of the data:
There you have it. They conclude, “People return to their baseline weight within 1.7 years on average after stopping treatment with any weight-management medication, and just 1.5 years after using semaglutide or terzepatide.”[v] Such has been my experience as well.
So, complete weight regain is the norm. Some studies have looked at ways to mitigate regain (using metformin, for instance), but so far, none of them have been successful.
[i] In fairness to Google, their answer did technically endorse the possibility of complete weight regain. I still deduct points because the rest of the answer heavily suggested “partial weight regain” was the reality.
[ii] Google’s AI is trained on the published medical literature and popular media commentary about those studies. It seems to be, at least. Google doesn’t have the advantage that I do, which is that I knew the correct answer ahead of time. How? Well, I have been prescribing GLP-1 agonists for over twenty years, so I have long experience with what happens when patients stop them.
[iii] Why would they? Continuing to follow patients costs real money, and Eli Lilly, et al., who are the studies’ usual sponsors, have no clear incentive to go out of their way to prove that discontinuation of their meds leads to total weight regain.
[iv] Trying to educate yourself about a subject in medicine is sometimes described as trying to take a sip from a wide-open fire hydrant.
[v] West S, Scragg J, Aveyard P, Oke J L, Willis L, Haffner S J P et al. Weight regain after cessation of medication for weight management: systematic review and meta-analysis BMJ 2026; 392 :e085304 doi:10.1136/bmj-2025-085304