Retatrutide — dosage, half-life & reference guide

Metabolic & GLP-1 peptide · also known as LY3437943

The world's first triple-agonist — it activates GLP-1, GIP, and glucagon receptors simultaneously. The glucagon component adds increased energy expenditure on top of appetite suppression, which is unique among incretin drugs. Phase II data showed 24% body weight loss at 48 weeks — the highest number recorded for any drug in this class. Not yet FDA-approved.

Commonly-researched dose ranges

Retatrutide is commonly researched at 1–12 mg, weekly, by SubQ injection. These are reference ranges from the literature and community use, not a prescription.

Half-life

Estimated half-life: ~6 days. See how it accumulates in the half-life calculator.

Safety & interactions

In the Phase 2 obesity trial (Jastreboff et al., NEJM 2023), the most common adverse events were dose-dependent gastrointestinal (nausea up to ~60% at 12 mg, vomiting, diarrhea, constipation), mostly mild-moderate and concentrated during dose escalation; discontinuation for adverse events ran 6-16% and serious adverse events were ~4% (comparable to placebo). As a triple GIP/GLP-1/glucagon agonist it produced a dose-dependent mean resting heart-rate rise of ~5-7 bpm (peaking ~week 24). As a GLP-1-class agent it carries the class rodent thyroid C-cell signal and trial-monitored gallbladder/pancreatitis considerations. These are trial findings, not personal predictions — discuss with your clinician.

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