How much bacteriostatic water for a 15 mg Retatrutide vial?

Adding 2.5 mL of bacteriostatic water to a 15 mg Retatrutide vial yields 6 mg/mL — 60 mcg in every insulin unit. The reconstituted vial holds 250 units of solution in total.

How many units is a 6 mg dose of Retatrutide at 15 mg in 2.5 mL?

6 mg is 1 mL of this mix, which is 100 units on a U-100 insulin syringe (a U-100 barrel is enough).

How many 6 mg doses does a 15 mg vial give?

A 15 mg vial contains 2 full 6 mg doses. Using more or less bacteriostatic water changes the units you draw, never the number of doses in the vial.

Retatrutide 15 mg reconstituted with 2.5 mL

Concentration

6mg/mL

Per insulin unit: 60 mcg
Solution in vial: 250 u
6 mg draw: 100 u

Math utility only — not medical advice. Not a recommended dose.

Units per dose at 6 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	0.167 mL	16.7 u	U-30	15
2 mg	0.333 mL	33.3 u	U-50	7
4 mg	0.667 mL	66.7 u	U-100	3
6 mg	1 mL	100 u	U-100	2
8 mg	1.333 mL	133.3 u	split draw	1

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
15 mg ÷ 2.5 mL = 6 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 6 mg dose
6 mg ÷ 6 mg/mL = 1 mL
3 · Insulin units
1 mL × 100 = 100 units
Every unit on the barrel carries 60 mcg at this concentration, so misreading by one unit is a 60 mcg error.

See it on a real syringe

The interactive calculator draws this 6 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 15 mg Retatrutide vial?: Adding 2.5 mL of bacteriostatic water to a 15 mg Retatrutide vial yields 6 mg/mL — 60 mcg in every insulin unit. The reconstituted vial holds 250 units of solution in total.
How many units is a 6 mg dose of Retatrutide at 15 mg in 2.5 mL?: 6 mg is 1 mL of this mix, which is 100 units on a U-100 insulin syringe (a U-100 barrel is enough).
How many 6 mg doses does a 15 mg vial give?: A 15 mg vial contains 2 full 6 mg doses. Using more or less bacteriostatic water changes the units you draw, never the number of doses in the vial.

Other Retatrutide mixes

Other compounds

All 211 reconstitution combinations →