Retatrutide Dose Calculator
Working out a retatrutide draw? Enter your vial size, the bacteriostatic water you're adding, and your weekly dose — this free retatrutide dose calculator converts it into exact insulin-syringe units, with your vial's concentration and doses-per-vial alongside.
100 units per mL — pick the syringe you have.
Draw to
BAC water
on a U-100 insulin syringe
Drag the syringe to set your dose, or type the values above.
Enter your vial amount and dose, then type the bacteriostatic water or drag the syringe to see the exact units to draw.
Chips and prefilled values are commonly used numbers shown for convenience — not recommendations. Enter your own vial, dose, and water.
Never do this math twice.
The Pep AI app remembers your vials and doses, shows an interactive syringe you draw to, counts down the doses left in each vial, and reminds you when it's time. Free on iOS and Android.
How the retatrutide math works
Retatrutide is only available as a lyophilized research vial, so reconstitution math is unavoidable. Three steps take your numbers to a syringe draw:
1. Concentration
Vial amount ÷ water added. A 10 mg vial with 2 mL of water is 5 mg/mL.
2. Volume per dose
Your dose ÷ concentration. A 1 mg dose at 5 mg/mL is 0.2 mL.
3. Units to draw
Volume per dose × 100 for a U-100 syringe (or × 40 for a U-40). 0.2 mL on a U-100 syringe is 20 units.
Worked example
You have a 10 mg vial, you want a 1 mg dose, and you add 2 mL of bacteriostatic water. Concentration is 10 ÷ 2 = 5 mg/mL. Volume per dose is 1 ÷ 5 = 0.2 mL. On a U-100 syringe that's 0.2 × 100 = 20 units, and the vial holds 10 doses.
Retatrutide in context
Retatrutide is an investigational triple agonist (GIP, GLP-1, and glucagon receptors) that has not been approved by any regulator — there are no pens and no prefilled anything. Everything in circulation is a research-grade lyophilized vial, which is why, unlike semaglutide or tirzepatide, every retatrutide user has to do reconstitution math.
Published clinical trials studied weekly doses in the 1–12 mg range with gradual escalation, which is why the quick-pick chips above sit in low single-digit milligrams. As with any titrating compound, the units you draw change every time the dose does — a 1 mg draw from a 10 mg vial with 2 mL of water is 20 units, but step the dose up and the same vial reads differently on the syringe.
Because retatrutide protocols evolve week to week, saving the math matters: the Pep AI app stores your vial and reconstitution, converts each week's dose automatically, and keeps your history — see the peptide tracker for how it fits together.
Frequently asked questions
This calculator is provided for informational and educational purposes only and is not medical advice. Always confirm dosing with a qualified healthcare professional and double-check your own measurements before administering anything.