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How-to · reconstitution
In this example, 1 mL of bacteriostatic water in a 30 mg Retatrutide vial gives 30.00 mg/mL. An example 2 mg amount is then 6.7 units on a U-100 syringe.
More water makes a weaker mix and a bigger draw. Less water makes a stronger mix and a smaller one. The amount of Retatrutide stays the same. Use the diluent and volume specified for your product; the arithmetic alone does not choose them.
| Water added | Concentration | Per U-100 unit | Example: 2 mg = |
|---|---|---|---|
| 1 mL | 30.00 mg/mL | 300 mcg | 6.7 units |
| 2 mL | 15.00 mg/mL | 150 mcg | 13.3 units |
Straight arithmetic: concentration = 30 mg ÷ liquid volume, and 1 U-100 unit = 0.01 mL. The example column shows the math at 2 mg; it is not a dose recommendation.
The table compares possible concentrations; it does not establish which diluent or volume suits your product. Follow its dispensing instructions.
“Hard to measure” means the example draw is below two U-100 units. “Won’t fit” means it exceeds this syringe’s capacity.
Retatrutide is an experimental weekly injection being tested for weight loss. It acts on three hormone signals linked to appetite and metabolism.
The table above uses one worked example. These are the published quantities, converted into marks on a U-100 barrel at each listed liquid volume for a 30 mg vial. Where a quantity was never studied by injection, the row says so.
1–12 mg once weekly, under the skin.
| Water added | Concentration | Draw, low to high |
|---|---|---|
| 1 mL | 30.00 mg/mL | 3.3 to 40.0 units |
| 2 mL | 15.00 mg/mL | 6.7 to 80.0 units |
Human trialJastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med 2023;389:514-26 (PMID 37366315) · retrieved 2026-08-12
The vial holds fifteen worked doses. Both water options put the draw between syringe lines, while the two smaller vial sizes land on whole units.
The vial size and worked amount do not divide evenly with either water option. The exact draw falls between syringe lines in both cases.
The exact figure stays visible so you can compare it with the illustrated marks. A small fractional difference is still a difference in the represented dose; the table does not decide whether rounding is acceptable for a person or product.
The vial divides into fifteen worked amounts, but no product-specific storage limit is assigned to this example. Fifteen doses does not establish fifteen weeks of use.
A storage limit would need to apply to the specific prepared product. The quantity remaining in a vial cannot show whether that product is still suitable to use, even if the calculation gives another complete dose.
Inserting a higher amount from the listed trial rows reduces the portion count and increases the draw at the same concentration. The study rows keep those amounts attached to their trial context.
Inserting a lower amount does the reverse. Neither calculation establishes a storage duration or reproduces the trial product, and it cannot tell you which studied amount would be appropriate outside that trial.
The calculator lets you enter your product’s vial strength and mixing volume, then shows the arithmetic for your syringe.
Open the Retatrutide calculator →The arithmetic on this page is only half the question. These are the pages that carry the other half.