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How-to · reconstitution
In this example, 1 mL of bacteriostatic water in a 10 mg Retatrutide vial gives 10.00 mg/mL. An example 2 mg amount is then 20.0 units on a U-100 syringe.
This example lands on a syringe line. 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 | 10.00 mg/mL | 100 mcg | 20.0 units |
| 2 mL | 5.00 mg/mL | 50 mcg | 40.0 units |
Straight arithmetic: concentration = 10 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 10 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 | 10.00 mg/mL | 10.0 to 120.0 unitswon’t fit |
| 2 mL | 5.00 mg/mL | 20.0 to 240.0 unitswon’t fit |
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
At the worked amount, the vial contains five doses. Both water options land exactly on syringe lines, although the compound has no approved prescribing label.
Five is the number of complete doses at the worked amount, before any drawing losses. That count does not establish five weeks of storage or repeated use of a particular container.
The preparation and storage instructions would need to describe the actual product. An example that names only an ingredient, vial strength and liquid volume cannot supply those missing instructions.
Each water option lands the worked dose exactly on a syringe line, so no rounding is needed.
That will not hold across the whole ladder. The largest retatrutide vial breaks it.
A whole-number draw only proves that the arithmetic divided evenly. It does not prove that the vial, water or entered amount was correct.
The published study amounts listed alongside the example span more than tenfold. A smaller entered amount gives more portions from the same vial; a larger one gives fewer.
The study rows provide context for those different quantities, not instructions to choose an arm of a trial. A trial dose also does not establish how a separate powder product should be prepared.
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.