Research reference
Retatrutide dosage: what the clinical trials actually used
The most useful dosing reference is the published trial record. This guide summarises the dose arms, titration schedules and pharmacokinetics from retatrutide's Phase 2 and Phase 3 programmes — as a research reference. It is not medical advice, and research compounds are not for human consumption.
The published dose arms
Retatrutide’s headline data comes from the 48-week Phase 2 obesity trial published in the New England Journal of Medicine (2023), which randomised participants across placebo and four weekly dose arms:
| Weekly dose arm | Starting dose | Mean weight change at 48 weeks |
|---|---|---|
| 1 mg | 1 mg | −8.7% |
| 4 mg | 2 mg, titrated | −17.1% |
| 8 mg | 2–4 mg, titrated | −22.8% |
| 12 mg | 2 mg, titrated 4-weekly | −24.2% |
| Placebo | — | −2.1% |
Titration: the pattern across every arm
No trial arm started at its target dose. Higher-dose participants began at 2 mg weekly and stepped up at roughly 4-week intervals — 2 mg → 4 mg → 8 mg → 12 mg — a pattern common to the whole incretin class, driven by gastrointestinal tolerability. The practical consequence for researchers reading the literature: reported outcomes at a given dose reflect participants who reached that dose gradually, not immediate exposure.
Pharmacokinetic publications report a half-life of approximately six days, supporting the once-weekly interval used throughout the programme.
Measuring research quantities accurately
Research work with retatrutide uses either lyophilised vials (reconstituted with bacteriostatic water) or pre-mixed dial-dose pens at fixed concentrations. For vials, concentration = peptide (mg) × 1000 ÷ water volume (ml); our peptide calculator does the conversion to draw volumes and syringe units. Pens remove the calculation — each strength’s documentation states the amount dispensed per click.
Research-grade retatrutide
Pens and vials for laboratory research use, third-party tested batch by batch with certificates of analysis available.
Frequently asked questions
What retatrutide doses were used in the clinical trials?
What retatrutide doses were used in the clinical trials?
Why do trials titrate retatrutide gradually?
Why do trials titrate retatrutide gradually?
How do retatrutide pen clicks translate to doses?
How do retatrutide pen clicks translate to doses?
What is the half-life of retatrutide in research?
What is the half-life of retatrutide in research?
Related reading
All products sold by RegenMed are supplied strictly for laboratory research purposes only and are not for human consumption. Nothing on this page is medical advice, and no statement has been evaluated by the MHRA or FDA. Content summarising published research is provided for educational purposes.