KeptSwitching from an injection to a GLP-1 pill: what happened to weight in the trial
- In the ATTAIN-MAINTAIN trial, people who switched from semaglutide shots to the orforglipron pill kept about 79% of their weight loss after a year, vs about 38% with placebo.
- People switching from tirzepatide kept about 75%, vs about 49% with placebo. On average that group regained roughly 11 lb over the year.
- So a switch protects most of the loss for most people, but not all of it. The first 12 weeks are the time to watch closely.
- Whether and how to switch is a decision for you and your prescriber. Kept never advises on medication.
Since Foundayo (orforglipron) was approved in April 2026 and the Wegovy pill launched, a lot of people on weekly injections are asking the same question: if I move to a daily pill, will I keep my weight off? There's now a trial built to answer exactly that.
What the trial did
ATTAIN-MAINTAIN took adults who had already lost weight and reached a plateau on injectable tirzepatide (Zepbound, Mounjaro) or semaglutide (Wegovy, Ozempic). They were randomly assigned to a once-daily orforglipron pill or a placebo pill, and followed for 52 weeks.
What happened to weight
| Switched from | Share of loss kept on the pill | Share kept on placebo |
|---|---|---|
| Semaglutide (Wegovy, Ozempic) | about 79% | about 38% |
| Tirzepatide (Zepbound, Mounjaro) | about 75% | about 49% |
Two things stand out. First, the pill held most of the loss, far better than stopping. Second, people coming from tirzepatide, which tends to produce the bigger losses, regained more in absolute terms. Reports of the trial put the average at about 11 lb (5 kg) over the year for that group, and about 2 lb for people coming from semaglutide.
These are averages. Some people held everything, and some regained more. That spread is the reason to watch your own numbers rather than rely on the average.
How to watch a switch
- Write down your switch-day weight. Use your 7-day average in the week you make the change, not a single morning.
- Weigh daily, judge weekly. Daily weight swings by 2 to 4 lb with water and salt. The weekly average is what tells you something.
- Pick your line. Decide in advance the gain that makes you act, for example 3 lb above your switch-day average.
- Watch appetite as well as weight. If hunger or food noise rises in the first weeks, that usually shows up before the scale moves. Note it, and mention it to your prescriber.
- Keep the habits that held the weight. Protein at every meal, strength work twice a week and a consistent eating pattern matter just as much on a pill.
Kept has a 12-week switch watch built in: it compares your weekly average with your switch-day weight and flags it if you cross your line.
Common questions
Will I regain weight if I switch from Zepbound to Foundayo?
In the ATTAIN-MAINTAIN trial, people switching from tirzepatide to orforglipron kept about 75% of their loss after a year on average, with an average regain of roughly 11 lb. Many people kept more, some kept less. Watching your weekly average for the first 12 weeks shows you which way you're heading.
Is switching from Wegovy to a pill as good as staying on the shot?
The trial compared the pill with placebo, not with staying on the injection, so it doesn't answer that directly. People switching from semaglutide kept about 79% of their loss on the pill. Talk to your prescriber about what fits you.
How long should I watch my weight after switching?
The first 12 weeks are the most useful window, because that's when appetite and weight changes from the switch tend to show. After that, a normal maintenance routine of daily weigh-ins and a weekly average works.
Does Kept tell me whether to switch?
No. Kept never advises on medication. It tracks your weight, appetite and habits around whatever you and your prescriber decide.
Sources
- ATTAIN-MAINTAIN: switching from injectable semaglutide or tirzepatide to once-daily oral orforglipron. Nature Medicine, 2026 (press release with results). Link
- A Study of Orforglipron for the Maintenance of Body Weight Reduction (ATTAIN-MAINTAIN). ClinicalTrials.gov NCT06584916. Link
- FDA approves Eli Lilly's Foundayo (orforglipron) weight-loss pill, April 2026. Link