Retatrutide 15 mg reconstitution calculator

With 1.5 mL of water, a 15 mg vial is 10 mg/mL (100 mcg per unit), the same as the 10 mg vial with 1 mL or the 30 mg vial with 3 mL. With 3 mL it’s 5 mg/mL (50 mcg per unit), like the 10 mg vial with 2 mL. With 2 mL it’s 7.5 mg/mL (75 mcg per unit), a strength none of the other example volumes make. At equal strength, the same mg takes the same units; what changes is that this vial holds 1.5 times what a 10 mg vial holds, so it lasts for more draws.

Water is measured in mL, and on a U-100 syringe 1 mL is 100 units. So 1.5 mL is 150 units, 2 mL is 200 units and 3 mL is 300 units: more than a 100-unit syringe holds in one fill. Measuring the water in two or three fills means two or three chances to miscount, and an error in the water changes the strength of every draw that follows. Ask your pharmacist which syringe to use for adding the water, and write the total volume and the strength on the vial once it’s mixed.

No retatrutide product appears on the FDA’s list of novel drug approvals for 2026 (current as of October 9, 2026), so there is no approved vial in any strength and no label behind a 15 mg size (FDA). In 2026 the FDA sent warning letters to sellers of retatrutide labeled “research use only”, in March and in August (FDA, FDA). It says products like these have been sold directly to consumers for human use with dosing instructions, despite their labels (FDA). Whatever the vial says, the calculator can only work from that number, so ask a pharmacist before mixing.