This is the question people ask least often before starting and most often around month six. It deserves a straight answer, because it shapes whether treatment makes sense for you at all.

The short version

Most people regain a substantial share of the weight they lost.

This is not a failure of willpower and it is not unique to any one medication. It is what the follow-up data shows, and it follows directly from how these drugs work.

Why it happens

GLP-1 receptor agonists work while they are in your system. They slow gastric emptying and act on the appetite signalling in your brain — effects that stop when the medication stops.

Within weeks of discontinuing, appetite typically returns toward where it was. The food preoccupation that quietened down tends to come back. Portions that felt like plenty start feeling like not enough again.

There is also a physiological piece that has nothing to do with the drug: after weight loss, the body reduces energy expenditure and adjusts hunger hormones in ways that favour regain. That happens after weight loss by any method, and it is part of why sustained loss is difficult without ongoing support.

What the follow-up data shows

In the extension study following STEP 1, participants who stopped semaglutide regained most of the weight they had lost within about a year, and the cardiometabolic improvements moved back toward baseline alongside it.

Follow-up on tirzepatide showed the same pattern: participants switched to placebo after the initial treatment period regained substantially, while those who continued maintained their loss.

The consistent finding across programmes is that these medications work as ongoing treatment rather than a course you complete.

What this means before you start

It reframes the decision. The realistic question is not “how much will I lose in six months” but “is this something I can sustain, and what happens if I cannot?”

Worth thinking through in advance:

Cost over time, not just the first month. Introductory pricing is common across this industry. Budget against the recurring price, since that is what the second year looks like.

What your plan is if you stop. Whether by choice, cost, side effects or supply — having thought about it beforehand is better than improvising.

Whether the rest is in place. In every trial the medication was paired with diet and activity change. Those habits are what carry over when the medication does not.

If you are stopping

Talk to your provider first rather than simply not refilling. There may be reasons to taper, to switch, or to address a side effect that would let you continue.

If you are stopping regardless, the same conversation is worth having: what to expect, what to watch, and what support exists for maintenance. Regain is common but it is not automatic or total, and people who keep the structural changes tend to hold more of the loss.

The honest framing

Any program presenting GLP-1 treatment as a short-term fix is describing something the evidence does not support. Anyone promising you will keep the weight off after stopping is making a claim the follow-up data contradicts.

That does not make the medication less useful. It makes it a treatment for an ongoing condition rather than a course with an end date — which is how obesity is increasingly understood clinically, and a more honest basis for deciding than a before-and-after photo.

If you want a provider’s view on whether this fits your situation, the medical intake is free and you are charged only if treatment is deemed appropriate.

References

Wilding JPH, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes, Obesity and Metabolism, 2022. doi:10.1111/dom.14725
Aronne LJ, et al. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction (SURMOUNT-4). JAMA, 2024. doi:10.1001/jama.2023.24945