Retatrutide 5 mg reconstitution calculator
How much bac water for retatrutide 5 mg?
There’s no single right amount: the water sets the strength, not how much retatrutide is in the vial, so use the volume on your pharmacy’s instructions. For example, 1 mL makes 5 mg/mL and 2 mL makes 2.5 mg/mL; the table below shows what each volume means on a U-100 syringe.
Your retatrutide vial
Syringe
1 mL · 2-unit marks
Work backwards
Find the water for a given reading in units.
Enter your numbers to see the result.
Enter your numbers
This is arithmetic, not medical advice. Confirm with your prescriber or pharmacist.
How our calculator worksAdvanced
Vial capacityOptional
The volume printed on the vial or its box, not the mg. We’ll tell you if the water won’t fit.
What each volume makes
| Water | Strength | Each unit | 1 mg is |
|---|---|---|---|
| 1 mL | 5 mg/mL | 50 mcg | 20 units |
| 2 mL | 2.5 mg/mL | 25 mcg | 40 units |
| 2.5 mL | 2 mg/mL | 20 mcg | 50 units |
Examples; use the volume on your pharmacy’s instructions. Units are on a U-100 syringe: 100 units = 1 mL.
About the 5 mg vial
Half the strength of the 10 mg vial at the same water
With the same water, this vial is half as strong as the 10 mg vial: 2 mL makes 2.5 mg/mL here (25 mcg per unit) and 5 mg/mL there (50 mcg per unit). So the same syringe reading holds half as much, and units worked out for one vial size don’t carry over to the other. Equal strength takes half the water: 5 mg in 1 mL and 10 mg in 2 mL are both 5 mg/mL. If you move between vial sizes, enter the new vial and water above and work out the units again from the mg your prescriber gave you.
More units for the same mg
This is the weakest mix of the retatrutide vial sizes on this site: 20 to 50 mcg per unit at the example volumes, against 40 to 100 mcg in the 10 mg vial and 80 to 200 mcg in the 20 mg vial. A weaker mix means the same mg takes more units: easier to read on the syringe, but more liquid to inject, and the reading can run past the scale of a 30 or 50-unit syringe. If the units the calculator gives you are more than your syringe holds, check the water and the mg with a pharmacist before you draw.
No approved 5 mg vial exists
Retatrutide is not a component of any FDA-approved drug, so no label sets the water for this vial and nothing official has checked the 5 mg printed on it (FDA). The calculator can only trust the number on the label, so every figure on this page is arithmetic on an unverified amount.
Sources for these notes
About retatrutide
US regulatory status
Investigational, not approved
Retatrutide is not approved by the FDA for any use and has no brand name. Eli Lilly published phase 3 trials in 2026, but no FDA filing or approval had been announced as of October 16, 2026. The FDA says retatrutide cannot be used in compounding, and it has warned telehealth companies, ingredient distributors and websites selling “research use only” retatrutide.
As of
Sources (7)
- Novel Drug Approvals for 2026U.S. Food and Drug Administration, 2026 (opens in a new tab)
- Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of ObesityN Engl J Med, 2026 (opens in a new tab)
- Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2): a double-blind, parallel-group, randomised, placebo-controlled, phase 3 trialLancet, 2026 (opens in a new tab)
- A Study of Retatrutide (LY3437943) in Participants Who Have Obesity or Overweight (TRIUMPH-1), NCT05929066ClinicalTrials.gov, 2026 (opens in a new tab)
- FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight LossU.S. Food and Drug Administration, 2026 (opens in a new tab)
- Warning letter: Gram Peptides (MARCS-CMS 721806)U.S. Food and Drug Administration, 2026 (opens in a new tab)
- Warning letter: TXP Innovations LLC dba Tex Peptides (MARCS-CMS 735067)U.S. Food and Drug Administration, 2026 (opens in a new tab)
How this retatrutide calculator works
This calculator starts from the 5 mg in your vial. Add the water you mix it with and the dose your prescriber gave you; it divides the mg by the mL to get the strength, then turns your dose into mL and units on a 30, 50 or 100-unit syringe.
Peptinote never suggests a dose or a water volume. The example volumes are there to make the math easy to check, not as advice. For the full method, see the peptide calculator.
Questions people ask
How much bacteriostatic water should I mix with retatrutide 5 mg?
There’s no single right amount: use the volume on your pharmacy’s instructions. The water only sets the strength; the vial still holds 5 mg however much you add. With 1 mL it’s 5 mg/mL (50 mcg per unit), with 2 mL 2.5 mg/mL (25 mcg per unit) and with 2.5 mL 2 mg/mL (20 mcg per unit). Enter your volume and prescribed dose above to get the units. This product isn’t FDA-approved, so no official label sets a water volume and its contents aren’t verified.
How much bacteriostatic water do you add to 5mg retatrutide?
Whatever volume you add, only the strength changes; the vial still holds 5 mg. More water spreads it out, so each unit holds less and the same dose takes more units: easier to measure, but more liquid to inject. Going from 1 mL to 2.5 mL takes each unit from 50 mcg to 20 mcg. Check the volume on your pharmacy’s instructions first. This product isn’t FDA-approved, so no official label sets a water volume and its contents aren’t verified.
How do I reconstitute retatrutide 5 mg?
Wipe both stoppers with alcohol and let them dry. Draw the volume of bacteriostatic water your pharmacy specifies into a new syringe, add it slowly down the inside of the vial, then swirl gently until clear; don’t shake. Label it with the strength: 5 mg in 1 mL is 5 mg/mL. Full steps: how to reconstitute peptides.
What are the steps to reconstitute retatrutide 5 mg?
Mixing your retatrutide 5 mg vial takes the bacteriostatic water your pharmacy specifies and a new sterile syringe. Add the water slowly against the glass and swirl, never shake, until the liquid is clear. If it stays cloudy or has particles, don’t use it; call your pharmacy. Then write the strength and date on the vial and store it as the label says (how to store peptides).
Can Peptinote tell me how many units to take?
No. Peptinote never suggests a dose. Enter the dose your prescriber gave you, and the calculator shows how to measure it: the units, the mL and where the line sits on your syringe, with every step of the math. If you aren’t sure what your dose is, ask your prescriber or pharmacist before drawing anything. How our calculator works.
Other retatrutide vial sizes
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Every result is plain arithmetic from formulas we publish in full and check with automated tests. Peptinote doesn’t suggest doses and never sells or links to sellers of peptides.