One of the most important questions to ask about a GLP-1 isn't "how much will I lose?" It's "what happens when I stop?" The biggest trial to answer that for tirzepatide is called SURMOUNT-4, and its results are worth understanding before you begin — because they should shape how you choose a provider.
What the trial did
SURMOUNT-4 gave 670 adults with obesity 36 weeks of tirzepatide first. Then it split them into two groups: half kept taking the medication for another year, and half switched to a placebo. The point was to see what the drug's ongoing benefit actually is — and what happens when it's taken away.
What it found
The two groups moved in opposite directions. The people who kept taking tirzepatide continued to lose weight, reaching a total of around 26% of their starting body weight. The people who switched to placebo regained — on average about 14% of their body weight came back over the year. Alongside the regain, some of the early improvements in blood pressure, blood sugar and other markers began to reverse, too.
In plain terms: for most people in the trial, stopping meant giving back a meaningful share of what they'd worked to lose. This tracks with how doctors increasingly describe obesity — as a chronic condition, more like high blood pressure than a one-time fix. The medication manages it; it doesn't cure it.
What this doesn't mean
It does not mean the weight loss was "fake" or that you're doomed to regain everything the moment you stop. Averages hide a lot of variation — some people hold their loss better than others, especially with strong habits around protein, strength training and sleep in place. And "stopping" in a trial is abrupt; a thoughtful, gradual taper guided by a clinician is a different thing. The honest headline is simply that weight regain after stopping is common, and worth planning for.
The provider question this raises
Here's why this matters for how you choose. A provider who's only set up to get you started — quick intake, prescription, ship — isn't set up for the part that actually determines your long-term result. The providers worth your money are the ones with a real plan for maintenance: how they taper, whether they offer a lower maintenance dose, and how they keep supporting you once the fast loss slows down.
That's exactly why our Care Standard scores maintenance as its own dimension, and why our guide to keeping muscle matters more than the number on the scale. Before you sign up anywhere, ask one question: what does month 12 look like with you?