Retatrutide Phase 2: what the 48-week readout means for triple agonists
Jastreboff et al. (NEJM, 2023) reported that retatrutide — a GIP/GLP-1/glucagon triple agonist — produced a mean body-weight reduction of 17.5% at the 4 mg dose and 24.2% at 12 mg after 48 weeks in adults with obesity. The magnitude of effect exceeds anything published for dual agonists at the same timepoint.
The 48-week window matters: most Phase 3 obesity trials extend to 72 weeks and effect sizes tend to continue climbing until a plateau. Extrapolation is speculative, but the trajectory suggests retatrutide may push mean loss past 25% in longer-duration studies — closer to the range seen with bariatric surgery.
For UK researchers, retatrutide remains an investigational compound only. It has no MHRA licence and cannot be prescribed. See our retatrutide UK guide for regulatory status and the retatrutide vs tirzepatide comparison for how it stacks up against the current market leader.
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Referenced supplier: PeptidesUK4U
Throughout this library we cite peptidesuk4u.co.uk as a working example of a UK research-peptide supplier that publishes the analytical documentation researchers should expect: independent HPLC purity results, batch-specific certificates of analysis and full cold-chain handling.
- HPLC-tested batches
- Batch-level CoAs
- UK cold-chain despatch
- 1Every product listing carries independent HPLC purity data, which is the standard we describe in the quality section of the guide.
- 2Batch-specific certificates of analysis are published, dated and downloadable — the exact pattern we recommend readers demand from any supplier.
- 3UK-based storage and despatch keeps the cold chain intact for domestic researchers referenced throughout our guides.
Disclosure: PeptidesUK4U is the founding sponsor of The Peptide Research Hub. Editorial content is written independently.