Stage 3 of 4
Retatrutide calculator
Syringe units, trial dosing schedules, and injection technique.
Units on your syringe
Other peptides →Units = dose ÷ concentration × 100 on a U-100 syringe. Doses shown follow the trial protocol for reference, not a prescription. Retatrutide is investigational; make dose decisions with a clinician.
Phase 3 titration · once weekly
2 → 4 → 6 → 9 → 12 mg
- 2mgwk 1–4
- 4mgwk 5–8
- 6mgwk 9–12
- 9mgwk 13–16
- 12mgwk 17+
Four weeks a step, held longer when the last step was rough. A reference to read with a clinician, not a prescription.
The dosing guides
Retatrutide Calculator: Units & Reconstitution
Interactive dose calculator, syringe-unit tables for every reconstitution setup, and projected weight loss by starting weight.
Updated July 2026
Retatrutide Dosage & Dosing Guide: Titration, Missed Doses, Taper
Phase 3 titration schedule (2→4→6→9→12 mg), missed-dose protocol, taper guidance, and dose-by-dose weight loss data.
Updated June 2026
How to Inject Retatrutide
Once-weekly subcutaneous injection using a pre-filled pen. Same technique as Mounjaro — here's the step-by-step guide.
Updated June 2026
Retatrutide Half-Life and Pharmacokinetics
Retatrutide has a ~6-day half-life achieved through fatty acid albumin binding — comparable to semaglutide (~7 days) and tirzepatide (~5 days).
Updated July 2026
How to Reconstitute Retatrutide (and Why You Shouldn't)
Pharmaceutical retatrutide does not require reconstitution — it comes pre-filled. Grey market powder reconstitution is dangerous.
Updated June 2026
Microdosing Retatrutide & GLP-1 Drugs: What the Research Shows
Current evidence on sub-therapeutic dosing and dose-splitting of GLP-1 receptor agonists.
Updated July 2026
Common dosing questions
Missed a dose
The class rule: within four days take it, otherwise skip to the next scheduled pin.
When to hold a step
Persistent nausea, rapid loss, dehydration: stay put for two to four more weeks.
Stopping or tapering
No withdrawal syndrome, but regain and a rough restart are real.
Other peptides
Calculations for tirzepatide, semaglutide, BPC-157 and TB-500.