Reconstitution and dose maths
Retatrutide reconstitution calculator
A 10 mg vial with 2 mL of bacteriostatic water gives 5 mg/mL, so a 2 mg dose is 0.4 mL: 40 units on a U-100 insulin syringe. Pick your vial, water and dose below; the syringe shows the draw as you drag.
Updated 30 August 2026. Ledger figures captured 30 August 2026.
The arithmetic, shown
- 10 mg in the vial ÷ 2 mL of water = 5.00 mg/mL
- 2.000 mg per dose ÷ 5.00 mg/mL = 0.400 mL
- 0.400 mL × 100 = 40 units on a U-100 syringe
Your vial
Vial size (mg)
Bacteriostatic water added (mL)
What the calculator is doing
Milligrams in the vial, units on the barrel.
Common draws
The usual vials, worked out.
Retatrutide circulates as a vial-only compound: there is no pen and no pharmacy product to copy numbers from. Vials run 5 to 30 mg in ordinary circulation, doses are set in whole milligrams, and every draw below fits a standard U-100 syringe.
| Vial | Water added | Concentration | Dose | Draw to | Doses in the vial |
|---|---|---|---|---|---|
| 5 mg | 2 mL | 2.50 mg/mL | 1 mg | 40 units | 5 |
| 10 mg | 2 mL | 5.00 mg/mL | 2 mg | 40 units | 5 |
| 10 mg | 2 mL | 5.00 mg/mL | 4 mg | 80 units | 2 |
| 20 mg | 2 mL | 10.00 mg/mL | 2 mg | 20 units | 10 |
| 20 mg | 2 mL | 10.00 mg/mL | 4 mg | 40 units | 5 |
| 30 mg | 3 mL | 10.00 mg/mL | 6 mg | 60 units | 5 |
Each row is the calculator's three steps in print: vial ÷ water = mg/mL, dose ÷ mg/mL = volume, volume × 100 = units on a U-100 syringe. Doses in the vial is the labelled mass divided by the dose, rounded down.
No reference product
A compound with no pen to copy.
Tirzepatide and semaglutide users can sanity-check a dose against a pharmacy pen. Retatrutide has no approved product anywhere, so there is no official label to lean on: every number reaches you through a vendor page or a forum post. That makes the arithmetic the only part of the process you can be certain of, which is the point of doing it in the open. The three steps above are the whole calculation, and you can redo them by hand in under a minute.
And if you arrived here spelling it retratrutide, you are in large company. The extra r outranks the correct spelling in some search data, and misspelled listings appear in the lab archive itself. Spelling is no signal of quality in either direction; it just makes things harder to find.
The public record
The archive's most tested compound.
of the 201 tests in Janoshik's public archive name retatrutide in the listing, more than any other compound. Captured 30 August 2026.
A third of the whole public archive is retatrutide. Of the 74 listings, 30 claim a 20 mg vial and 10 claim 30 mg, with claimed sizes running from 5 up to 100 mg. A few are blends, retatrutide with cagrilintide in one vial, where one draw carries both compounds at once.
Read the volume as demand, not assurance. These listings come from manufacturers and resellers, publishing is optional, and one public report proves one batch was tested once. If your vial came with a report, verify it against the lab, and see the report ledger for who has actually published.
Questions
Retatrutide dose maths, asked directly.
How many units is 2 mg of retatrutide?+
At 5 mg/mL, which is a 10 mg vial reconstituted with 2 mL of bacteriostatic water, 2 mg is 0.4 mL: 40 units on a U-100 insulin syringe. At 10 mg/mL, from a 20 mg vial with the same 2 mL, it is 20 units. The dose never changes; the concentration decides the draw.
How much bacteriostatic water goes into a 10 mg retatrutide vial?+
Any amount that fits; the water sets the concentration, never the dose. 2 mL gives 5 mg/mL and keeps draws for 1 to 4 mg between 20 and 80 units, all readable on a standard U-100 syringe.
How many doses are in a 20 mg retatrutide vial?+
At 2 mg per dose, 10. At 4 mg per dose, 5. Divide the labelled vial mass by the dose and round down; the calculator does this in the doses-per-vial readout.
Is it retatrutide or retratrutide?+
Retatrutide. The extra r is one of the most common ways the compound is searched, and misspellings show up in the public test archive itself, where listings appear exactly as sellers typed them.
Other compounds
Same arithmetic, different defaults.
Tirzepatide calculator
Multi-dose vials against single-dose pens, and the overdraw mistake that follows.
Semaglutide calculator
The smallest doses of the GLP-1s: 0.25 to 2.4 mg, where a draw can shrink below readability.
BPC-157 calculator
Dosed in micrograms, which is exactly where the thousand-fold unit mistake lives.
GHK-Cu calculator
50 and 100 mg vials flip the usual problem: the risk is a draw too small to measure.
MOTS-c calculator
One vial size dominates the public record, and one public assay shows why labels are claims.
All compounds
The same calculator with the full compound picker, TB-500 included.
Research use only
MechPeptides sells nothing. Retatrutide is named on this page so the arithmetic has a label on it. It is an investigational compound with no approved product anywhere, it is not a dietary supplement, and nothing on this site is medical advice or a recommended protocol.
The calculator performs arithmetic on numbers you enter. It converts a vial mass and a diluent volume into a concentration, then into a volume and a U-100 syringe reading. It does not know your compound, it does not recommend a dose, and its slider bounds are display ranges rather than guidance. Confirm every calculation independently before acting on it.