Retatrutide (LY3437943)
LY3437943
Clinical trials are ongoing or recently completed. Final approval has not been granted.
An investigational once-weekly injection that works on three different appetite and metabolism pathways at once, producing some of the most significant weight loss results seen in clinical trials -- up to about 29% body weight reduction over about 16 months. It is not yet FDA-approved.
This entry is a cited research summary, not an established treatment reference. Dosing language is included as source context, not as medical instruction.
Retatrutide (LY3437943) has substantial clinical evidence but is not FDA-approved.
Clinical trials are ongoing or recently completed. Final approval has not been granted.
Safety Summary
Most adverse effects are gastrointestinal, dose-dependent, and concentrated during initial dose-titration; they generally improve with continued use. Discontinuation rates due to AEs in Phase 3 TRIUMPH-4: 12.2% (9 mg), 18.2% (12 mg), 4.0% (placebo). Dysesthesia is a novel signal at higher doses requiring ongoing monitoring -- more frequent in Phase 3 data (~20.9% at 12 mg) than initially suggested by Phase 2 data. Heart rate increases typically peak around 24 weeks then decline. No excess major adverse cardiac events in Phase 2. Rodent C-cell thyroid tumors observed in class-wide nonclinical studies (GLP-1/GIP agonists) -- limited human relevance but a recognized nonclinical signal. Post-discontinuation weight regain is anticipated based on GLP-1RA class data but not yet directly documented for retatrutide, doi:10.1056/nejmoa2301972
Clinical check-in
If real-world use or exposure is being considered, review potential interactions, contraindications, and monitoring needs with a licensed clinician rather than relying on summary copy alone.
Cited sources
Every claim on this page links to one of the 10 sources below. Identifiers are PubMed (PMID), ClinicalTrials.gov (NCT), or DOI; click through to the source of record before acting on a claim.
- 1PMID 37366313PubMed
- 2PMID 37385280PubMed
- 3doi:10.1038/s41591-024-03018-2DOI
- 4NCT05931367ClinicalTrials.gov
- 5doi:10.1038/s41421-024-00700-0DOI
- 6doi:10.1016/S1550-4131(22)00312-6DOI
- 7Efficacy and safety of retatrutide: a systematic review and meta-analysis of RCTsReference
- 8PMID 41787737PubMed
- 9Retatrutide--A Game Changer in Obesity PharmacotherapyReference
- 10Effect of retatrutide on kidney parametersReference