Retatrutide before and after: what the trial actually measured

TL;DR

- The strongest "before and after" evidence for retatrutide comes from one source: the Jastreboff et al., 2023 phase 2 trial. Its figures are group averages, not personal photos or promises. - In that 48-week trial, the highest dose group averaged about 24.2 percent body-weight reduction, versus about 2.1 percent for placebo (Jastreboff et al., 2023). - Change scaled with dose and time: the 12 mg group averaged about 17.5 percent at 24 weeks and about 24.2 percent at 48 weeks, and the curve had not flattened (Jastreboff et al., 2023). - For context in separate trials, tirzepatide reached about 22.5 percent (Jastreboff et al., 2022) and semaglutide about 15 percent (Wilding et al., 2021). - Trial data on related drugs shows much of the lost weight tends to return after the medicine stops (Wilding et al., 2022; Aronne et al., 2024), so "after" is not a fixed endpoint.

What does "retatrutide before and after" actually mean in the research?

In published research, the closest thing to a retatrutide before and after is the group-average body-weight change measured in the Jastreboff et al., 2023 phase 2 trial, not a set of personal transformation images.

That trial studied 338 adults with obesity over 48 weeks in a randomized, double-blind, placebo-controlled design (Jastreboff et al., 2023). Retatrutide is an investigational triple receptor agonist, acting on the GIP, GLP-1, and glucagon receptors. A group mean is the average change across everyone assigned to a dose, so it smooths out the person who lost a lot and the person who lost little. That is a different thing from an individual result, and it is a very different thing from a photo posted online with no verified dose, diet, or timeline.

How much weight did people lose in the retatrutide trial, by dose?

In the Jastreboff et al., 2023 trial, average body-weight reduction at 48 weeks rose with dose, from about 8.7 percent in the 1 mg group to about 24.2 percent in the 12 mg group, against about 2.1 percent for placebo.

Reported group-mean body-weight reduction (Jastreboff et al., 2023):

These are least-squares mean changes for dose groups, reported in a controlled study. They are not guaranteed individual results, and they are not a recommendation to use any amount. The dose figures describe what researchers assigned in the trial, framed as research-reported data only.

How did the "after" change over time in the trial?

Reductions kept growing across the full 48 weeks, and the authors reported that weight loss had not reached a plateau by the end of the study (Jastreboff et al., 2023).

You can see the trend in the table above: the 4 mg group moved from about 12.9 percent at 24 weeks to about 17.1 percent at 48 weeks, and the 8 mg group moved from about 17.3 percent to about 22.8 percent. A still-declining curve at week 48 suggests the average may not have hit its floor within the study window, and the trial authors said as much: weight loss had not plateaued by the end of the study (Jastreboff et al., 2023). This was a 48-week phase 2 snapshot, and longer completed human outcome data for retatrutide is limited in the sources here.

How does retatrutide's reported weight change compare to tirzepatide and semaglutide?

Across separate trials that were not run head-to-head, retatrutide's top dose group reached a higher peak group mean than tirzepatide or semaglutide did in their own studies.

Read this table with care. The three numbers come from different trials with different designs, populations, and durations, and no one measured them side by side. Retatrutide reached its figure in a shorter window, which is notable, but a cross-trial comparison cannot prove one compound is better than another. It only shows what each study reported on its own.

What happens to the "after" if someone stops?

Trial data on related drugs shows a meaningful share of lost weight tends to return after the medication is stopped (Wilding et al., 2022; Aronne et al., 2024).

The STEP 1 extension found that participants regained a large portion of their lost weight in the year after stopping semaglutide (Wilding et al., 2022). SURMOUNT-4 found weight regain after tirzepatide was withdrawn (Aronne et al., 2024). One reason is adaptive thermogenesis: after weight loss, the body burns fewer calories and defends a higher set point (Rosenbaum and Leibel, 2010). There is no long-term retatrutide-specific withdrawal data in these sources, so this pattern extrapolates from related compounds. The takeaway is that "after" is a point in time under active treatment, not a permanent state, and any plan around this belongs with a qualified clinician.

Are the retatrutide before-and-after photos online reliable?

Personal photos are not controlled data, because they lack a documented dose, timeline, diet, exercise record, and independent verification, so they cannot stand in for a trial's measured group averages.

Photos posted online have no placebo group, no denominator, and no way to confirm what actually happened. Selection bias means the most dramatic images spread fastest, while people who saw little change rarely post. Lighting, posture, and editing add more noise. Retatrutide is also an investigational compound, not an approved medicine, so the information on this page is educational. When you want to know what change looks like on average, the Jastreboff et al., 2023 trial is the evidence, not a gallery.

What side effects did the trial report?

The most common adverse events reported were gastrointestinal, including nausea, diarrhea, vomiting, and constipation, and they were dose-related and mostly mild to moderate (Jastreboff et al., 2023).

Higher dose groups tended to report more of these events, which fits the pattern seen across this drug class. This page does not describe how to manage side effects. Questions about safety for any one person route to a qualified clinician.