Retatrutide reconstitution calculator

Peptide in vial (mg)Total mg printed on the vial

BAC water added (mL)Bacteriostatic water you reconstitute with

Desired dose (mg)

Syringe sizeStandard U-100 insulin syringe

Educational use only. This tool and content are for general information and do not constitute medical advice, diagnosis, or treatment. Peptides and GLP-1 medications should only be used under the supervision of a licensed healthcare provider. Always confirm dosing with your prescriber and the product label. Some peptides discussed are not approved by the FDA for human use.

About retatrutide

Retatrutide (Eli Lilly’s LY3437943) is an investigational triple agonist that activates the GLP-1, GIP and glucagon receptors. In Phase 2 trials it produced some of the largest weight reductions yet reported for this drug class. As of 2026 it remains in Phase 3 testing and is not approved by the FDA, so it cannot be legally prescribed or sold as a finished medicine in the United States.

Dose ladder studied in trials (reference only)

Reflects weekly doses evaluated in Eli Lilly Phase 2 research (NEJM, 2023). Investigational — not an approved or recommended dosing schedule.

This ladder is shown for education only. It is not a prescription, a recommendation, or a substitute for a clinician.

Important: retatrutide is not FDA-approved

Retatrutide is still in Phase 3 trials and cannot be legally prescribed or sold as a finished drug in the U.S. If you want a clinician-supervised, FDA-approved GLP-1 for weight loss today, a licensed telehealth provider can assess whether semaglutide or tirzepatide is right for you.

See FDA-approved options →Find a retatrutide trial

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Frequently asked questions

How do I calculate retatrutide units?

Enter the milligrams in your vial, the bacteriostatic water you added, and your target dose. The calculator returns the exact units on a U-100 insulin syringe and draws the fill line.

Is retatrutide FDA approved?

No. As of 2026 retatrutide is still in Phase 3 clinical trials and is not approved for sale or prescription in the U.S. Products sold online as “research” retatrutide are not regulated medicines.

How much BAC water for a 10 mg retatrutide vial?

That’s your choice — it sets concentration. 1–2 mL is common. Try both in the calculator to see which makes your dose easiest to measure.

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Retatrutide dosage calculator