How much bacteriostatic water for a 15 mg Retatrutide vial?

Adding 5 mL of bacteriostatic water to a 15 mg Retatrutide vial yields 3 mg/mL — 30 mcg in every insulin unit. The reconstituted vial holds 500 units of solution in total.

How many units is a 2 mg dose of Retatrutide at 15 mg in 5 mL?

2 mg is 0.667 mL of this mix, which is 66.7 units on a U-100 insulin syringe (a U-100 barrel is enough).

How many 2 mg doses does a 15 mg vial give?

A 15 mg vial contains 7 full 2 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 5 mL

Concentration

3mg/mL

Per insulin unit: 30 mcg
Solution in vial: 500 u
2 mg draw: 66.7 u

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

Units per dose at 3 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	0.333 mL	33.3 u	U-50	15
2 mg	0.667 mL	66.7 u	U-100	7
4 mg	1.333 mL	133.3 u	split draw	3
6 mg	2 mL	200 u	split draw	2
8 mg	2.667 mL	266.7 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 ÷ 5 mL = 3 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 2 mg dose
2 mg ÷ 3 mg/mL = 0.667 mL
3 · Insulin units
0.667 mL × 100 = 66.7 units
Every unit on the barrel carries 30 mcg at this concentration, so misreading by one unit is a 30 mcg error.

See it on a real syringe

The interactive calculator draws this 3 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 5 mL of bacteriostatic water to a 15 mg Retatrutide vial yields 3 mg/mL — 30 mcg in every insulin unit. The reconstituted vial holds 500 units of solution in total.
How many units is a 2 mg dose of Retatrutide at 15 mg in 5 mL?: 2 mg is 0.667 mL of this mix, which is 66.7 units on a U-100 insulin syringe (a U-100 barrel is enough).
How many 2 mg doses does a 15 mg vial give?: A 15 mg vial contains 7 full 2 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 →