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.
Retatrutide BAC water 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 |
|---|---|---|---|---|---|---|
| 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.
Choosing BAC water for retatrutide
For a 10 mg vial: 1 mL gives 10 mg/mL (a 2 mg dose = 20 units), 2 mL gives 5 mg/mL (2 mg = 40 units), and 3 mL gives 3.33 mg/mL (2 mg = 60 units).
Because retatrutide doses are in the milligram range, very low water volumes keep draws small but make small dose adjustments harder to measure.
- 10 mg / 1 mL = 10 mg/mL → 2 mg = 20 units
- 10 mg / 2 mL = 5 mg/mL → 2 mg = 40 units
- 10 mg / 3 mL = 3.33 mg/mL → 2 mg = 60 units
Why retatrutide BAC water decisions differ from semaglutide
Retatrutide doses run roughly an order of magnitude higher than semaglutide on a milligram basis. A typical semaglutide maintenance dose is 1.7 mg per week; a typical retatrutide trial dose ranges from 2 to 8 mg per week. That changes what a sensible concentration looks like.
Practical implication: a setup that gives semaglutide users a 10–20 unit draw will land retatrutide users at 40–80 units for an equivalent dose. The lower end of a U-100 syringe (under 10 units) is therefore less of a constraint for retatrutide — you do not need to dilute as much to get readable draws.
At higher doses (6–10 mg per week), a 2 mL reconstitution of a 10 mg vial requires drawing more than a milliliter. That either means multiple sub-draws or moving to a higher concentration (less BAC water) so each dose fits in a single 1 mL syringe pull.
- Retatrutide doses are roughly 10× larger than semaglutide on a mg basis
- Under-10-unit draws are rare with retatrutide — different BAC-water trade-off than semaglutide
- Doses above ~6 mg/week may require lower BAC water volume to keep draws ≤1 mL
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