Does a "50 mL bottle" mean the same thing as a 50 mg vial?

Almost always, yes. People say "mL" when they mean the amount of peptide, which is measured in mg. The glass vial itself is usually 3 mL regardless of whether it holds 50 mg or any other amount. The number on the label is milligrams of Retatrutide.

What happens if I add more or less water than recommended?

Nothing bad. You get the same total amount of peptide at a different concentration, so you draw a different number of units for the same dose. More water means a larger, easier-to-measure draw; less water means a smaller one.

How many units is a 12 mg dose?

At 2.5 mL of bacteriostatic water, a 50 mg vial is 20 mg/mL, so 12 mg is 0.6 mL, which is 60 units on a U-100 insulin syringe.

Can I use sterile water instead of bacteriostatic water?

No. Sterile water has no preservative, so a multi-dose vial mixed with it has to be used immediately. Bacteriostatic water contains 0.9% benzyl alcohol, which is what makes 28–60 day refrigerated storage possible.

How much bacteriostatic water for a 50mg Retatrutide vial?

Answer

Add 2.5 mL of bacteriostatic water to a 50 mg Retatrutide vial. That gives 20 mg/mL, so a 12 mg dose is 60 units on a U-100 insulin syringe. Note: a "50 mL bottle" almost always means a 50 mg vial. The glass itself is usually 3 mL.

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50mg Retatrutide reconstitution: how much water?

Bacteriostatic water options for a 50 mg vial

Water added	Concentration	Units for 12 mg	Doses per vial
0.5 mL	100 mg/mL	12	4
1 mL	50 mg/mL	24	4
1.5 mL	33.33 mg/mL	36	4
2 mL	25 mg/mL	48	4
2.5 mL ← recommended	20 mg/mL	60	4
3 mL	16.67 mg/mL	72	4
3.5 mL	14.29 mg/mL	84	4
4 mL	12.5 mg/mL	96	4

The recommended volume is the one that puts your dose on a clean syringe marking without filling the whole barrel.

Dose chart: 50 mg vial in 2.5 mL

Dose	Volume	U-100 units	U-40 units	Doses per vial
0.25 mg	0.013 mL	1.3	0.5	200
0.5 mg	0.025 mL	2.5	1	100
0.75 mg	0.038 mL	3.8	1.5	66
1 mg	0.05 mL	5	2	50
1.5 mg	0.075 mL	7.5	3	33
2 mg	0.1 mL	10	4	25
2.5 mg	0.125 mL	12.5	5	20
3 mg	0.15 mL	15	6	16
3.5 mg	0.175 mL	17.5	7	14
4 mg	0.2 mL	20	8	12
5 mg	0.25 mL	25	10	10
6 mg	0.3 mL	30	12	8
7 mg	0.35 mL	35	14	7
8 mg	0.4 mL	40	16	6
9 mg	0.45 mL	45	18	5
10 mg	0.5 mL	50	20	5
11 mg	0.55 mL	55	22	4
12 mg	0.6 mL	60	24	4

Doses that would need more than a full 1 mL syringe are omitted. Use less bacteriostatic water for those.

Common questions

Does a "50 mL bottle" mean the same thing as a 50 mg vial?: Almost always, yes. People say "mL" when they mean the amount of peptide, which is measured in mg. The glass vial itself is usually 3 mL regardless of whether it holds 50 mg or any other amount. The number on the label is milligrams of Retatrutide.
What happens if I add more or less water than recommended?: Nothing bad. You get the same total amount of peptide at a different concentration, so you draw a different number of units for the same dose. More water means a larger, easier-to-measure draw; less water means a smaller one.
How many units is a 12 mg dose?: At 2.5 mL of bacteriostatic water, a 50 mg vial is 20 mg/mL, so 12 mg is 0.6 mL, which is 60 units on a U-100 insulin syringe.
Can I use sterile water instead of bacteriostatic water?: No. Sterile water has no preservative, so a multi-dose vial mixed with it has to be used immediately. Bacteriostatic water contains 0.9% benzyl alcohol, which is what makes 28–60 day refrigerated storage possible.

Run your own numbers

These figures assume the vial and water volumes named above. Change either one and the units change with it.

Reconstitution calculator How this is calculated