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Free tool · Educational only

Retatrutide Dosage Calculator

Enter your vial strength, the bacteriostatic water you added, and a dose — this calculator shows the concentration, the volume to draw, and the units on a standard U-100 insulin syringe. It’s a reconstitution math tool for educational reference only.

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Retatrutide is investigational and not FDA-approved for human use. This calculator performs reconstitution arithmetic for educational purposes only. It is not medical advice or a directive to prepare or administer anything. See our Affiliate Disclosure.




Concentration—
Volume to draw—
Units (U-100 syringe)—

A U-100 insulin syringe has 100 units per 1 ml, so “units” = volume to draw × 100. Adding more water lowers the concentration and raises the units for the same dose.

How it works

The reconstitution math, explained

Concentration = peptide in vial ÷ water added. A 10 mg vial with 2 ml of BAC water gives 5 mg/ml. To draw a 2 mg dose you’d pull 0.4 ml — which is 40 units on a U-100 insulin syringe. The total peptide never changes; more water just spreads it across more liquid, so each unit holds less.

Reference

Trial dose escalation for context

People usually reach for this calculator while following the trial-style escalation ladder. For the schedule those doses came from, and weight-loss results by dose, see the full retatrutide dosage guide.

Weeks Dose (12 mg target)
1–4 2 mg
5–8 4 mg
9–12 6 mg
13–16 8 mg
17+ 12 mg

Looking for a GLP-1 you can actually get prescribed?

Retatrutide isn’t available by prescription. Compare vetted providers for approved options like semaglutide and tirzepatide.

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Answers

Calculator FAQ

How do you calculate retatrutide units on an insulin syringe?
Divide the vial strength by the water added to get concentration (mg/ml), divide your dose by that concentration to get the volume in ml, then multiply by 100 for units on a U-100 syringe. The calculator above does this automatically.
Does more bacteriostatic water change the dose?
No — it changes concentration, not the total peptide. More water means a larger volume (more units) for the same dose, which some people find easier to measure accurately.
How much BAC water should I add to a 10 mg vial?
Commonly 1–2 ml. 1 ml gives 10 mg/ml; 2 ml gives 5 mg/ml. This is reconstitution math only, not a recommendation to prepare or use anything.

Where to get retatrutide

Editor’s picks from our full vendor review. We may earn a commission — it never changes your price.

  1. #1 ZevayStreamlined GLP-1 telehealth Visit site
  2. #2 ReadyRxFast approvals on weight-loss meds Visit site
  3. #3 TrimRxPersonalized programs, US pharmacies Visit site
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