Retatrutide 20 mg reconstituted with 4 mL
Concentration
5mg/mL
- Per insulin unit
- 50 mcg
- Solution in vial
- 400 u
- 4 mg draw
- 80 u
Math utility only — not medical advice. Not a recommended dose.
Units per dose at 5 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 | 0.2 mL | 20 u | U-30 | 20 |
| 2 mg | 0.4 mL | 40 u | U-50 | 10 |
| 4 mg | 0.8 mL | 80 u | U-100 | 5 |
| 6 mg | 1.2 mL | 120 u | split draw | 3 |
| 8 mg | 1.6 mL | 160 u | split draw | 2 |
Amber rows exceed 100 units — more than one full U-100 barrel. That dose needs a larger draw or a stronger mix (less water).
How this is calculated
1 · Concentration
20 mg ÷ 4 mL = 5 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 4 mg dose
4 mg ÷ 5 mg/mL = 0.8 mL
3 · Insulin units
0.8 mL × 100 = 80 units
Every unit on the barrel carries 50 mcg at this concentration, so misreading by one unit is a 50 mcg error.
See it on a real syringe
The interactive calculator draws this 5 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 4 mL of bacteriostatic water to a 20 mg Retatrutide vial yields 5 mg/mL — 50 mcg in every insulin unit. The reconstituted vial holds 400 units of solution in total.
- How many units is a 4 mg dose of Retatrutide at 20 mg in 4 mL?
- 4 mg is 0.8 mL of this mix, which is 80 units on a U-100 insulin syringe (a U-100 barrel is enough).
- How many 4 mg doses does a 20 mg vial give?
- A 20 mg vial contains 5 full 4 mg doses. Using more or less bacteriostatic water changes the units you draw, never the number of doses in the vial.