Written by PX1 Research Team
PX1 chemists and research educators with hands-on experience in US-based peptide manufacturing, HPLC / mass-spectrometry lot testing, and endotoxin QC. All content is citation-backed and peer-reviewed for accuracy.
Retatrutide Results Timeline: What the Trial Data Showed Week by Week
Research Guide
Reviewed By
PX1 QC — Analytical Chemistry Team
Every article is reviewed by PX1's in-house analytical team for accuracy on mechanism, dosing ranges reported in the literature, and lab-handling guidance. We do not publish clinical or medical advice.
Quick answer
Published Phase 2 retatrutide outcomes mapped across 24 and 48 weeks — body weight, hepatic fat, and HbA1c by dose arm, with the caveats that matter.
Key takeaways
- Hepatic fat. Participants with elevated liver fat at baseline showed large reductions, with a substantial proportion reaching normalization thresholds in the higher-dose arms.
- HbA1c. Meaningful reductions across dose arms in the type 2 diabetes cohort.
- Blood pressure and lipids. Directionally favorable changes reported alongside weight reduction.
What "results" means here
Everything below is published clinical trial data, not anecdote. The Phase 2 obesity trial (Jastreboff et al., NEJM 2023) randomized participants to placebo or retatrutide at 1, 4, 8 or 12 mg weekly for 48 weeks with stepped titration.
Body weight by dose arm
| Dose arm | Week 24 (approx.) | Week 48 (approx.) |
|---|---|---|
| Placebo | ~2% | ~2% |
| 1 mg | ~7% | ~9% |
| 4 mg | ~12% | ~17% |
| 8 mg | ~15% | ~21% |
| 12 mg | ~17% | ~24% |
The 12 mg 48-week figure — roughly 24% mean body-weight reduction — was the largest reported for any incretin-class investigational compound at the time of publication, and notably the curves had not plateaued at week 48.
Other reported endpoints
- Hepatic fat. Participants with elevated liver fat at baseline showed large reductions, with a substantial proportion reaching normalization thresholds in the higher-dose arms.
- HbA1c. Meaningful reductions across dose arms in the type 2 diabetes cohort.
- Blood pressure and lipids. Directionally favorable changes reported alongside weight reduction.
Reading the timeline correctly
- Weeks 1–8 are titration, not steady state. Early-phase changes reflect a sub-therapeutic dose ramp.
- The separation between arms widens over time. Dose-response is not visible at week 8 the way it is at week 48.
- The curve was still descending at the study endpoint. Extrapolating beyond 48 weeks from this dataset is speculation.
- Trial conditions included structured lifestyle counseling in all arms, including placebo. That is why placebo is not zero.
Where retatrutide sits versus the rest of the class
Semaglutide (GLP-1) and tirzepatide (GLP-1/GIP) trials reported smaller mean reductions at their respective top doses. Retatrutide's third mechanism — glucagon receptor agonism — is the leading explanation for the additional effect through increased energy expenditure. Compare the pharmacology in tirzepatide vs semaglutide and the retatrutide research overview.
Research use only. Not for human consumption. Not intended to diagnose, treat, cure, or prevent any disease.