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How-to · reconstitution
In this example, 1 mL of bacteriostatic water in a 20 mg Retatrutide vial gives 20.00 mg/mL. An example 2 mg amount is then 10.0 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 | 20.00 mg/mL | 200 mcg | 10.0 units |
| 2 mL | 10.00 mg/mL | 100 mcg | 20.0 units |
Straight arithmetic: concentration = 20 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 20 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 | 20.00 mg/mL | 5.0 to 60.0 units |
| 2 mL | 10.00 mg/mL | 10.0 to 120.0 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
Twice the powder of the small vial and twice the doses, with both listed volumes still landing on syringe lines. It also produces a reading that already exists one page down the ladder.
Concentration is vial divided by water, so doubling both leaves it unchanged. Mixed into the larger listed volume, this vial gives precisely the strength and precisely the draw that the smallest vial gives at the smaller volume.
The matching result comes from doubling both inputs. It is valid only when the vial strength and liquid volume both match that ratio. A familiar unit count alone cannot confirm that you entered either value correctly.
The vial divides into ten worked amounts, but no product-specific storage limit is assigned to this example. Ten doses does not establish ten weeks of use.
The example supplies a conversion between drug mass and liquid volume. It does not establish the contents, stability or mixing instructions for an investigational product obtained outside the study.
Both water options land exactly on syringe lines. With the largest retatrutide vial, neither does because the worked amount no longer divides evenly.
Nothing about the compound changes between the two pages. The legibility of the answer does.
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.