With 1 mL bacteriostatic water
10.0 units
Page last checked
Reconstitution · Retatrutide
Retatrutide dosage calculator
Pick the vial, the water you added and the dose. Get the exact draw in units for the syringe in your hand.
Step 1 of 4
- total mg in the calculation
- mL used in the calculation
- mg
This vial holds 20 mg in total.
- match the size on the package
U-100 insulin syringe · 1 mL · lines every 2 units · 1 unit = 0.01 mL
Draw to
20.0units
20.0 units on a U-100 insulin syringe · 1 mL · lines every 2 units, which is 0.20 milliliters. The draw lands on a syringe line.
20 mg ÷ 2 mL = 10.00 mg/mL
→ 100 mcg/unit · 2 mg = 0.200 mL = 20.0 units
→ 100 mcg/unit · 2 mg = 0.200 mL = 20.0 units
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Show the math and syringe details
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How to use the calculator
- 1
Enter the amount in the vial
- 2
Enter the water you added
- 3
Enter the dose you want to convert
Retatrutide is an experimental weekly injection being tested for weight loss. It acts on three hormone signals linked to appetite and metabolism. People buy unapproved versions under the nickname Reta in hopes of losing weight.
A published phase 2 trial found large average weight loss. Phase 3 trials are underway, but FDA has not approved retatrutide.
Examples using 20 mg of Retatrutide
Each row uses 20 mg and the liquid volume shown. Dividing the amount by that volume gives the calculated concentration. The rows are arithmetic examples, not alternative product preparations.
◆ How liquid volume changes the resultdose used: 2 mg
With 2 mL bacteriostatic water
20.0 units
| Bacteriostatic water | Concentration | Per U-100 unit | Draw for 2 mg | Nearest syringe line |
|---|---|---|---|---|
| 1 mL | 20.00 mg/mL | 200.0 mcg | 10.0 u · 0.100 mL | exactly 10 u |
| 2 mL | 10.00 mg/mL | 100.0 mcg | 20.0 u · 0.200 mL | exactly 20 u |
The amount, liquid volume and dose shown here are the calculator’s starting example for Retatrutide. Replace them with your own values. Every result in the table is calculated from those inputs.
Retatrutide: a syringe reading depends on the whole calculation
A retatrutide amount in milligrams can correspond to different syringe readings. The vial strength and water volume determine the concentration. A unit count without those details does not tell you how much retatrutide it represents.
Open the mixing details3 notes
The presets are examples, not mixing instructions
This calculator includes several vial strengths and water volumes. Choosing a preset fills in the arithmetic; it does not establish how a particular preparation should be mixed. The tool cannot check the contents of a vial or supply instructions that are missing from it.
The study amounts shown on the page have their own research context. They do not turn the available presets into an approved product or a personal dosing schedule.
A change in concentration changes the reading
For the same amount of retatrutide, a more concentrated solution requires a smaller volume. A less concentrated solution requires a larger volume. That is why changing either the vial strength or the water can move the result along the syringe scale even when the entered dose stays the same.
The worked table shows these differences together. A small calculated volume may fall between syringe lines; a larger one may approach the syringe’s capacity. The measurement details explain those limits.
A copied unit count leaves out essential information
A syringe unit measures volume, not the mass of retatrutide. A saved reading from another calculation is only comparable when the dose, concentration and syringe type match.
The milligram amount and the syringe reading describe different parts of the same result. Keeping them together with the vial and water inputs lets you see why the answer changed, rather than treating the unit count as a dose on its own.
Retatrutide trial starting doses and target doses differ
In the published weight-loss trial, some groups began at a lower amount before reaching their assigned weekly dose. The dose entered in a calculator cannot describe that full course of treatment.
Read the supporting evidence3 supporting notes
Read the starting amount beside the target
The study compared groups with different target doses and starting amounts. Its results belong to those trial schedules, including the time spent increasing the dose. A single figure copied from the results table leaves that context out.
A trial result is not an individual forecast
Weight change was measured in trial participants over many months. The calculator only works out liquid volume from the values entered. It cannot predict weight change, side effects or whether a trial schedule suits a person.
The study does not identify an unrelated vial
A published retatrutide dose does not verify the strength, contents or storage life of a vial obtained outside that study. Those questions remain separate from the arithmetic shown here.
Read the starting amount beside the target
The study compared groups with different target doses and starting amounts. Its results belong to those trial schedules, including the time spent increasing the dose. A single figure copied from the results table leaves that context out.
A trial result is not an individual forecast
Weight change was measured in trial participants over many months. The calculator only works out liquid volume from the values entered. It cannot predict weight change, side effects or whether a trial schedule suits a person.
The study does not identify an unrelated vial
A published retatrutide dose does not verify the strength, contents or storage life of a vial obtained outside that study. Those questions remain separate from the arithmetic shown here.
Units to dose at 10.00 mg/mL
Mix 20 mg into 2 mL and one U-100 unit carries 100.0 mcg. The table shows how much peptide is in each numbered syringe line. These are conversion examples, not suggested doses.
Open the unit conversion table10 rows
| U-100 line | Volume | Mass (mcg) | Mass (mg) |
|---|---|---|---|
| 10 u | 0.10 mL | 1,000 mcg | 1 mg |
| 20 u | 0.20 mL | 2,000 mcg | 2 mg |
| 30 u | 0.30 mL | 3,000 mcg | 3 mg |
| 40 u | 0.40 mL | 4,000 mcg | 4 mg |
| 50 u | 0.50 mL | 5,000 mcg | 5 mg |
| 60 u | 0.60 mL | 6,000 mcg | 6 mg |
| 70 u | 0.70 mL | 7,000 mcg | 7 mg |
| 80 u | 0.80 mL | 8,000 mcg | 8 mg |
| 90 u | 0.90 mL | 9,000 mcg | 9 mg |
| 100 u | 1.00 mL | 10,000 mcg | 10 mg |
How the math works
- Concentration — divide the amount entered by the liquid volume used in the calculation: mg ÷ mL = mg/mL. This tells you how many mg are in each mL.
- Volume — the dose divided by that concentration: dose ÷ (mg/mL) = mL.
- Units — on a U-100 syringe one unit is 0.01 mL, so mL × 100 = units. A U-40 unit is 0.025 mL, so the wrong barrel is a 2.5× error. That is why the calculator asks which one you have.
- Rounding gap — the exact draw against the nearest syringe line: |exact − nearest line| ÷ exact × 100 = % difference.
Useful guides for this calculation
The math is only one part of the question. These guides cover the compound, published doses, side effects, mixing steps and supplies.
What a studied retatrutide figure is, and what it is not
When retatrutide reactions tend to appear
What retatrutide is, how it is used, and what has been studied
What the retatrutide draw needs from bacteriostatic water
The Hospira vial for a retatrutide vial
Buying the mixing water before the retatrutide arithmetic starts