PeptideOS
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Retatrutide

Triple agonist

Also known as: LY3437943

Tier 2, Investigational, human data

Studied in registered human trials with published pharmacokinetic data, but not approved. Dosing outside a trial protocol has no established safety margin.

Half-life
6.0 days · human data · subcutaneous

Half-life ~6 days (~144 h), enabling once-weekly SC dosing (stated in peer-reviewed phase 2a paper). Steady state ~4-5 weeks.

Model a dosing schedule →
Dosing
1000 - 12000 mcg

Phase 2 obesity trial: 1, 4, 8, or 12 mg once weekly with dose escalation every 4 weeks (starting doses 2 or 4 mg for higher target arms). Investigational, not an approved dosing regimen.

Titration
Investigational: dose escalations every 4 weeks toward target dose (e.g., start 2 mg, step to 4/8/12 mg) in the phase 2 program.
Frequency
Once weekly (investigational)
Regulatory status
Investigational (Eli Lilly). GIP/GLP-1/glucagon triple receptor agonist in phase 3 development; not approved.
Evidence base
human clinical · confidence: high

Published phase 2 randomized trials (obesity, MASLD); no regulatory label. Molecular weight not found in an allowed primary source.

Safety

Investigational; no boxed warning issued (no label). Trial adverse events predominantly gastrointestinal (nausea, diarrhea, vomiting), dose-dependent. Glucagon-agonist component may raise heart rate. Not for clinical dosing decisions.