Retatrutide dosage calculator
Work out the concentration and the exact insulin-syringe units for a reconstituted retatrutide vial. Enter how much peptide is in the vial, how much bacteriostatic water you add, and the dose you want to measure.
These values are an editable example to show how the calculator works — not a dosing recommendation. Enter your own vial size, water, and dose.
Retatrutide is a single molecule that acts on three receptors — GLP-1, GIP, and glucagon — which is why it is often called a triple agonist. It is supplied as a lyophilised (freeze-dried) powder, so no volume can be measured until it is reconstituted with bacteriostatic water.
The amount of water you add is entirely your choice: it changes only the concentration, and therefore how many syringe units a given dose works out to. Because retatrutide vials are commonly labelled anywhere from 5 mg to 20 mg, the same dose can sit at very different points on the syringe depending on how much water was used — which is exactly what this calculator resolves.
Common Retatrutide vial sizes are 5 mg, 10 mg, 15 mg, 20 mg.
Retatrutide is an investigational drug. As of 2026 it is not FDA-approved and is in Phase 3 trials — it is not a prescription medication or an approved treatment.
How to reconstitute Retatrutide
- 1Let both the peptide vial and the bacteriostatic water reach room temperature, and wipe each rubber stopper with an alcohol swab.
- 2Draw the amount of bacteriostatic water you entered above into a syringe.
- 3Add the water slowly, aiming the stream down the inside glass wall of the Retatrutide vial rather than directly onto the powder.
- 4Let the powder dissolve on its own; swirl gently if needed. Do not shake.
- 5Once the solution is clear, read the “draw to” figure above and draw that many units on a U-100 insulin syringe.
- 6Store the reconstituted vial as directed by your supplier — usually refrigerated — and note the date.