Quick math example
A 10 mg vial mixed with 2 mL gives 5 mg/mL. A 2 mg dose is 0.4 mL, which equals 40 units on a U-100 syringe.
Reconstitution reference
U100 units to draw for each common Retatrutide dose, by vial size, reconstituted with 2 mL of bacteriostatic water. Change the water volume in the calculator above to recompute for your own setup.
| Vial | Concentration | 1 mg | 2 mg | 4 mg | 8 mg | 12 mg |
|---|---|---|---|---|---|---|
| 5 mg | 2.5 mg/mL | 40 u(0.4 mL) | 80 u(0.8 mL) | 160 u(1.6 mL) | 320 u(3.2 mL) | 480 u(4.8 mL) |
| 10 mg | 5 mg/mL | 20 u(0.2 mL) | 40 u(0.4 mL) | 80 u(0.8 mL) | 160 u(1.6 mL) | 240 u(2.4 mL) |
Educational reference only — not a dose recommendation. Units assume a U100 insulin syringe (100 units = 1 mL on U-100). Always confirm against your own vial, diluent, and clinician or pharmacy instructions.
How the retatrutide calculation works
Retatrutide doses are typically discussed in milligrams while many vials and syringes require thinking in mg, mcg, mL, and units at the same time. The calculator handles all four conversions for you.
Concentration is solved first, then your target dose is divided by that concentration to return the draw volume and matching syringe units.
- 10 mg equals 10,000 mcg
- 10,000 mcg / 2 mL = 5,000 mcg per mL
- 2,000 mcg / 5,000 mcg per mL = 0.4 mL
Retatrutide 10 mg vial with 2 mL example
A 10 mg retatrutide vial mixed with 2 mL gives 5 mg/mL, or 5,000 mcg/mL.
A 2 mg target dose is 2,000 mcg. At 5,000 mcg/mL that is 0.4 mL, which equals 40 units on a U-100 syringe.
- 10 mg / 2 mL = 5 mg/mL
- 2 mg = 2,000 mcg
- 2,000 mcg / 5,000 mcg per mL = 0.4 mL = 40 U-100 units
Retatrutide 5 mg vial with 2 mL example
A 5 mg retatrutide vial mixed with 2 mL gives 2.5 mg/mL, or 2,500 mcg/mL — half the concentration of the 10 mg example.
Because the vial is more dilute, the same 2 mg dose now needs 0.8 mL, which equals 80 units on a U-100 syringe. A lower-strength vial always pushes the draw volume higher.
- 5 mg / 2 mL = 2.5 mg/mL
- 2,000 mcg / 2,500 mcg per mL = 0.8 mL
- 0.8 mL x 100 = 80 U-100 units
Choosing BAC water for a retatrutide titration
Retatrutide protocols usually start low and step up over several weeks, so it helps to pick a reconstitution volume that keeps both early and later doses on readable unit marks. More bacteriostatic water lowers the concentration and raises the units drawn for the same dose.
For a 10 mg vial: 1 mL gives 10 mg/mL (a 2 mg dose = 0.2 mL = 20 units), 2 mL gives 5 mg/mL (2 mg = 0.4 mL = 40 units), and 4 mL gives 2.5 mg/mL (2 mg = 0.8 mL = 80 units).
- More BAC water = lower concentration = more units per dose
- Aim for early titration steps that still land on clear unit lines
- Re-run the math each time you step the dose up
Frequently asked questions
Does this calculator tell me what retatrutide dose to take?+
How much BAC water should I use for a retatrutide vial?+
Why does my retatrutide draw volume change with vial size?+
Can PepSync track a retatrutide titration schedule?+
Primary sources
Full reference listBackground references for this calculator. PepSync does not make clinical claims; these citations support the educational context only.
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