Retatrutide 20 mg reconstituted with 0.5 mL
Concentration
40mg/mL
- Per insulin unit
- 400 mcg
- Solution in vial
- 50 u
- 8 mg draw
- 20 u
Math utility only — not medical advice. Not a recommended dose.
Units per dose at 40 mg/mL
Insulin syringes are graduated in hundredths of a millilitre, so units = mL × 100 on a U-100, U-50 or U-30 barrel alike.
| Dose | Volume | U-100 units | Fits | Doses per vial |
|---|---|---|---|---|
| 1 mg | 0.025 mL | 2.5 u | U-30 | 20 |
| 2 mg | 0.05 mL | 5 u | U-30 | 10 |
| 4 mg | 0.1 mL | 10 u | U-30 | 5 |
| 6 mg | 0.15 mL | 15 u | U-30 | 3 |
| 8 mg | 0.2 mL | 20 u | U-30 | 2 |
How this is calculated
1 · Concentration
20 mg ÷ 0.5 mL = 40 mg/mL
The peptide mass never changes — bacteriostatic water only sets how concentrated the solution is, and therefore how far the plunger travels.
2 · Volume for a 8 mg dose
8 mg ÷ 40 mg/mL = 0.2 mL
3 · Insulin units
0.2 mL × 100 = 20 units
Every unit on the barrel carries 400 mcg at this concentration, so misreading by one unit is a 400 mcg error.
See it on a real syringe
The interactive calculator draws this 40 mg/mL mix on a scaled U-100 barrel, shows when a draw lands exactly on a printed tick, and works backwards from a target dose to the water volume that makes it land cleanly.
Open the interactive calculator →Common questions
- How much bacteriostatic water for a 20 mg Retatrutide vial?
- Adding 0.5 mL of bacteriostatic water to a 20 mg Retatrutide vial yields 40 mg/mL — 400 mcg in every insulin unit. The reconstituted vial holds 50 units of solution in total.
- How many units is a 8 mg dose of Retatrutide at 20 mg in 0.5 mL?
- 8 mg is 0.2 mL of this mix, which is 20 units on a U-100 insulin syringe (a U-30 barrel is enough).
- How many 8 mg doses does a 20 mg vial give?
- A 20 mg vial contains 2 full 8 mg doses. Using more or less bacteriostatic water changes the units you draw, never the number of doses in the vial.