Dosage calculator
Retatrutide Dosage Calculator: Reconstitution and Units
Quick answer
Pick your vial (10 to 60 mg), the bac water you add and your dose to get the draw in mL and U-100 syringe units. A 10 mg retatrutide (reta) vial with 2 mL of bac water is 5 mg/mL, so a 2 mg dose is 0.4 mL, or 40 units. Mixing tables for every vial size are below.
- Updated October 17, 2026
- 2 sources
- Educational use · not medical advice
Retatrutide Calculator Tool
Enter your vial strength, BAC water volume, and target dose below. The calculator outputs concentration (mg/mL), draw volume (mL), and U-100 units. Educational and research use only.
Fills the calculator below. Choose your BAC water in the calculator.
On this page
How much bac water for each retatrutide vial size
Research vials of retatrutide, sometimes called GLP-3, are typically supplied as a powder that's mixed with BAC water. The water doesn't change how much retatrutide is in the vial, only how concentrated the mix is. Each answer uses a 2 mg dose, the same example this page uses above, so the mixes are easy to compare.
How much bac water for 10 mg retatrutide?
It's your choice: the water sets the strength of the mix, not the amount of retatrutide. With 1 mL, a 10 mg vial is 10 mg/mL and a 2 mg dose is 20 units on a U-100 syringe; 2 mL gives 5 mg/mL (40 units); 3 mL gives 3.33 mg/mL (60 units).
Every dose for a 10 mg vialHow much bac water for 12 mg retatrutide?
It's your choice: the water sets the strength of the mix, not the amount of retatrutide. With 1 mL, a 12 mg vial is 12 mg/mL and a 2 mg dose is 16.7 units on a U-100 syringe; 2 mL gives 6 mg/mL (33.3 units); 3 mL gives 4 mg/mL (50 units).
Every dose for a 12 mg vialHow much bac water for 15 mg retatrutide?
It's your choice: the water sets the strength of the mix, not the amount of retatrutide. With 1 mL, a 15 mg vial is 15 mg/mL and a 2 mg dose is 13.3 units on a U-100 syringe; 2 mL gives 7.5 mg/mL (26.7 units); 3 mL gives 5 mg/mL (40 units).
Every dose for a 15 mg vialHow much bac water for 20 mg retatrutide?
It's your choice: the water sets the strength of the mix, not the amount of retatrutide. With 1 mL, a 20 mg vial is 20 mg/mL and a 2 mg dose is 10 units on a U-100 syringe; 2 mL gives 10 mg/mL (20 units); 3 mL gives 6.67 mg/mL (30 units).
Every dose for a 20 mg vialHow much bac water for 30 mg retatrutide?
It's your choice: the water sets the strength of the mix, not the amount of retatrutide. With 1 mL, a 30 mg vial is 30 mg/mL and a 2 mg dose is 6.7 units on a U-100 syringe; 2 mL gives 15 mg/mL (13.3 units); 3 mL gives 10 mg/mL (20 units).
Every dose for a 30 mg vialHow much bac water for 40 mg retatrutide?
It's your choice: the water sets the strength of the mix, not the amount of retatrutide. With 1 mL, a 40 mg vial is 40 mg/mL and a 2 mg dose is 5 units on a U-100 syringe; 2 mL gives 20 mg/mL (10 units); 3 mL gives 13.33 mg/mL (15 units).
Every dose for a 40 mg vialHow much bac water for 50 mg retatrutide?
It's your choice: the water sets the strength of the mix, not the amount of retatrutide. With 1 mL, a 50 mg vial is 50 mg/mL and a 2 mg dose is 4 units on a U-100 syringe; 2 mL gives 25 mg/mL (8 units); 3 mL gives 16.67 mg/mL (12 units).
Every dose for a 50 mg vialHow much bac water for 60 mg retatrutide?
It's your choice: the water sets the strength of the mix, not the amount of retatrutide. With 1 mL, a 60 mg vial is 60 mg/mL and a 2 mg dose is 3.3 units on a U-100 syringe; 2 mL gives 30 mg/mL (6.7 units); 3 mL gives 20 mg/mL (10 units).
Every dose for a 60 mg vialRetatrutide Reconstitution by Vial Size
The doses are the ones already in this page's example table (1, 2 and 5 mg). They are examples for the math, not a recommended dose: retatrutide is investigational and has no approved dose.
- Each cell is the U-100 syringe reading for that dose, with the mL to draw under it.
- Over 1 mL more than a 1 mL (100-unit) syringe holds: the calculator splits it into more than one injection.
- Over vial the dose is more than the vial contains.
10 mg retatrutide vial
1 mL BAC water = 10 mg/mL · 2 mL BAC water = 5 mg/mL · 3 mL BAC water = 3.33 mg/mL
| Dose | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 1 mg | 10 units0.1 mL | 20 units0.2 mL | 30 units0.3 mL |
| 2 mg | 20 units0.2 mL | 40 units0.4 mL | 60 units0.6 mL |
| 5 mg | 50 units0.5 mL | 100 units1 mL | 150 units1.5 mLOver 1 mL |
12 mg retatrutide vial
1 mL BAC water = 12 mg/mL · 2 mL BAC water = 6 mg/mL · 3 mL BAC water = 4 mg/mL
| Dose | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 1 mg | 8.3 units0.0833 mL | 16.7 units0.17 mL | 25 units0.25 mL |
| 2 mg | 16.7 units0.17 mL | 33.3 units0.33 mL | 50 units0.5 mL |
| 5 mg | 41.7 units0.42 mL | 83.3 units0.83 mL | 125 units1.25 mLOver 1 mL |
15 mg retatrutide vial
1 mL BAC water = 15 mg/mL · 2 mL BAC water = 7.5 mg/mL · 3 mL BAC water = 5 mg/mL
| Dose | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 1 mg | 6.7 units0.0667 mL | 13.3 units0.13 mL | 20 units0.2 mL |
| 2 mg | 13.3 units0.13 mL | 26.7 units0.27 mL | 40 units0.4 mL |
| 5 mg | 33.3 units0.33 mL | 66.7 units0.67 mL | 100 units1 mL |
20 mg retatrutide vial
1 mL BAC water = 20 mg/mL · 2 mL BAC water = 10 mg/mL · 3 mL BAC water = 6.67 mg/mL
| Dose | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 1 mg | 5 units0.05 mL | 10 units0.1 mL | 15 units0.15 mL |
| 2 mg | 10 units0.1 mL | 20 units0.2 mL | 30 units0.3 mL |
| 5 mg | 25 units0.25 mL | 50 units0.5 mL | 75 units0.75 mL |
30 mg retatrutide vial
1 mL BAC water = 30 mg/mL · 2 mL BAC water = 15 mg/mL · 3 mL BAC water = 10 mg/mL
| Dose | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 1 mg | 3.3 units0.0333 mL | 6.7 units0.0667 mL | 10 units0.1 mL |
| 2 mg | 6.7 units0.0667 mL | 13.3 units0.13 mL | 20 units0.2 mL |
| 5 mg | 16.7 units0.17 mL | 33.3 units0.33 mL | 50 units0.5 mL |
40 mg retatrutide vial
1 mL BAC water = 40 mg/mL · 2 mL BAC water = 20 mg/mL · 3 mL BAC water = 13.33 mg/mL
| Dose | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 1 mg | 2.5 units0.025 mL | 5 units0.05 mL | 7.5 units0.075 mL |
| 2 mg | 5 units0.05 mL | 10 units0.1 mL | 15 units0.15 mL |
| 5 mg | 12.5 units0.13 mL | 25 units0.25 mL | 37.5 units0.38 mL |
50 mg retatrutide vial
1 mL BAC water = 50 mg/mL · 2 mL BAC water = 25 mg/mL · 3 mL BAC water = 16.67 mg/mL
| Dose | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 1 mg | 2 units0.02 mL | 4 units0.04 mL | 6 units0.06 mL |
| 2 mg | 4 units0.04 mL | 8 units0.08 mL | 12 units0.12 mL |
| 5 mg | 10 units0.1 mL | 20 units0.2 mL | 30 units0.3 mL |
60 mg retatrutide vial
1 mL BAC water = 60 mg/mL · 2 mL BAC water = 30 mg/mL · 3 mL BAC water = 20 mg/mL
| Dose | 1 mL | 2 mL | 3 mL |
|---|---|---|---|
| 1 mg | 1.7 units0.0167 mL | 3.3 units0.0333 mL | 5 units0.05 mL |
| 2 mg | 3.3 units0.0333 mL | 6.7 units0.0667 mL | 10 units0.1 mL |
| 5 mg | 8.3 units0.0833 mL | 16.7 units0.17 mL | 25 units0.25 mL |
How to Calculate Retatrutide Dosage
Three steps convert any vial and BAC water combination into the exact volume to draw on a U-100 insulin syringe.
Step 1 — Calculate concentration (mg/mL)
Divide the total peptide in the vial (mg) by the volume of BAC water you added (mL). For example: a 5 mg Retatrutide vial reconstituted with 2 mL BAC water gives 5 ÷ 2 = 2.5 mg/mL.Step 2 — Calculate draw volume (mL)
Divide your target dose (mg) by the concentration (mg/mL). For a 0.5 mg dose at 2.5 mg/mL: 0.5 ÷ 2.5 = 0.2 mL. This is the exact volume to draw into the syringe.Step 3 — Convert to U-100 syringe units
Multiply the draw volume (mL) by 100. For 0.2 mL: 0.2 × 100 = 20 U-100 units. Read this number on the unit markings of a standard insulin syringe.
Dosage Formula
Concentration formula
Concentration (mg/mL) = Vial mg ÷ BAC water mLDraw volume formula
Draw volume (mL) = Dose (mg) ÷ Concentration (mg/mL)U-100 syringe units
U-100 units = Draw volume (mL) × 100These three formulas apply to any Retatrutide vial, regardless of size. U-100 is the standard insulin-syringe scale: 100 units = 1 mL.
Example Retatrutide Calculations
Step-by-step worked examples using common vial sizes. Results are for illustrating the math only.
Example
10 mg vial + 2 mL BAC water, 2 mg dose
Given
- Vial
- 10 mg
- BAC water
- 2 mL
- Target dose
- 2 mg
Result
40 units
0.4 mL at 5 mg/mL
- Concentration: 10 ÷ 2 = 5 mg/mL
- Draw volume: 2 ÷ 5 = 0.4 mL
- U-100 units: 0.4 × 100 = 40 units
Example
10 mg vial + 5 mL BAC water, 2 mg dose
Given
- Vial
- 10 mg
- BAC water
- 5 mL
- Target dose
- 2 mg
Result
100 units
1 mL at 2 mg/mL
- Concentration: 10 ÷ 5 = 2 mg/mL
- Draw volume: 2 ÷ 2 = 1 mL
- U-100 units: 1 × 100 = 100 units
Example Retatrutide Dosage Table
Common vial and BAC water combinations with calculated concentration, draw volume, and U-100 syringe units. For education only — verify your vial label before use.
| Vial (mg) | BAC water (mL) | Concentration | Dose (mg) | Draw (mL) | U-100 units |
|---|---|---|---|---|---|
| 10 mg | 2 mL | 5 mg/mL | 1 mg | 0.2 mL | 20 units |
| 10 mg | 2 mL | 5 mg/mL | 2 mg | 0.4 mL | 40 units |
| 10 mg | 2 mL | 5 mg/mL | 5 mg | 1 mL | 100 units |
| 10 mg | 5 mL | 2 mg/mL | 2 mg | 1 mL | 100 units |
Retatrutide Reconstitution Guide
Retatrutide research vials are typically supplied as lyophilised powder. Reconstitute with bacteriostatic water:
- Swab both stoppers with alcohol.
- Draw desired BAC water volume; inject slowly along vial wall.
- Gently swirl until dissolved. Solution should be clear.
- Store refrigerated. Do not freeze.
Retatrutide (LY3437943) is an investigational triple-agonist (GLP-1, GIP, glucagon) and is not an approved therapy. All use is research only.
Important
For educational and research purposes only. Not medical advice. Consult a licensed healthcare professional before making any medical or health-related decisions.
Frequently Asked Questions
How do I calculate retatrutide draw volume?
Divide your dose (mg) by the concentration (mg/mL). For a 10 mg vial + 2 mL BAC: 5 mg/mL. For a 2 mg dose: 2 ÷ 5 = 0.4 mL = 40 U-100 units.
What are U-100 syringe units?
U-100 is the standard scale for insulin syringes. 100 units = 1.0 mL. That means 10 units = 0.1 mL, 50 units = 0.5 mL. Multiply any draw volume in mL by 100 to get the U-100 units reading.
Do I need to recalculate if I change the amount of BAC water?
Yes. Changing BAC water volume changes the concentration (mg/mL), which changes the draw volume for the same mg dose. Always recalculate using: concentration = vial mg ÷ BAC water mL, then draw volume = dose mg ÷ concentration.
What is retatrutide?
Retatrutide (LY3437943) is an investigational triple receptor agonist (GLP-1, GIP, and glucagon) studied for obesity and metabolic outcomes. It is not an approved therapy in most regions.
Is GLP-3 the same as retatrutide?
Yes. "GLP-3" is an informal nickname for retatrutide (LY3437943), which acts on three receptors: GLP-1, GIP and glucagon. It isn't an official drug name. This calculator works the same whichever name is on your vial label.
Sources & references
Context on this page comes from the retatrutide clinical trials listed below and the compound's investigational status. The math here helps translate vial strength into mL and U-100 units; it does not endorse unapproved use.
- Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 TrialPrimary phase 2 obesity trial that informs current efficacy and tolerability context.
- Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trialPhase 2a liver-disease trial that adds human metabolic and safety context.
Updated October 17, 2026