What happens when you stop
What happens if you stop taking a GLP-1?
On the two labels here that tested it, the weight comes back and so does most of what else the drug had moved. The largest result is Zepbound: after 36 weeks on the drug, the people randomly assigned to stop gained 14% of body weight over the following year while those who carried on lost 5.5% more — 19.5 points between the same patients, decided by nothing but whether the drug continued. 13 of the 15 drugs on this site have never been through a trial of this shape, and that is worth saying plainly rather than assuming the same thing happens.
Tested by stopping it
| Drug | On it first | Stopped | Carried on | Kept of the loss |
|---|---|---|---|---|
| Zepbound | 36 wks, −20.9% | +14% | -5.5% | 46% |
| Wegovy | 20 wks, −10% | +6.9% | -7.9% | 38% |
“Stopped” and “carried on” are changes from the day the drug was withdrawn, not from the start of the trial. “Kept of the loss” converts both to kilograms first, because the loss and the regain are percentages of different weights and dividing one by the other overstates the regain.
Never tested this way (13)
These labels carry no randomised withdrawal trial. Their trials compare the drug with placebo from the start, which measures what happens if you never take it rather than what happens if you stop. Anyone telling you the figures above apply to these is reasoning by analogy, which may well be right and is not a measurement.
Why this sits on a price site
Because it decides what the prices mean. Every comparison here comes to a yearly figure, and a yearly figure reads like the cost of getting somewhere. On these two drugs it is closer to a subscription: Zepbound at $5,388 a year, Wegovy at $4,188 a year, for as long as the result is wanted. No other comparison in this category prints the withdrawal figure beside the price, and the two facts only mean something together.
Questions
- Which weight-loss drugs have been tested by stopping them?
- 2 of the 15 on this site: Zepbound and Wegovy. Both labels carry a randomised withdrawal trial, where everyone takes the drug first and only those who reach the maintenance dose are then randomly assigned to continue or to switch to placebo. The other 13 have no such trial on their label, so what happens when they stop has not been measured this way.
- Why does it matter which trial design was used?
- Because the usual trial answers a different question. A placebo-controlled trial compares taking the drug with never taking it, and its result is the number every comparison page quotes. A withdrawal trial compares carrying on with stopping, in people who have already lost the weight — which is the situation a person is actually in when they ask whether they can come off.
- Does this mean the drugs are for life?
- These trials do not say that and this site will not. Each measured one year off the drug, in people who had tolerated it for months, with no attempt at a taper or a lower maintenance dose. What they establish is narrower and still worth knowing: stopping is not a neutral event, and a monthly price implies it is.