Convert a vial of FDA-approved reconstituted peptide medication into the exact volume to draw on a U-100 insulin syringe. Math, not medical advice.
Inputs
From the vial label (e.g. Egrifta SV = 1.4 mg)
Volume of diluent injected into the vial
Per-injection dose your prescriber set. 1 mg = 1,000 mcg.
Result
Concentration
—mg/mL
Volume to draw
—mL
U-100 syringe units
—units
Common FDA-approved scenarios
Click an example to load it into the calculator. Doses below match the FDA prescribing information.
Egrifta SV (tesamorelin) — HIV-related lipodystrophy
1.4 mg vial + 2.1 mL sterile water → daily 1.4 mg subcutaneous injection
Glucagon Emergency Kit — severe hypoglycemia rescue
1 mg vial + 1 mL diluent → 1 mg intramuscular or subcutaneous
Cortrosyn (cosyntropin) — adrenal-function diagnostic test
0.25 mg vial + 1 mL diluent → 250 mcg IV or IM stim test dose
Lupron Depot 3.75 mg (leuprolide) — endometriosis, fibroids (1-month depot)
3.75 mg microsphere vial + 1 mL diluent → entire vial intramuscular monthly
How the math works
Reconstitution converts a dry powder vial into a known concentration of liquid. Three steps:
- Concentration (mg/mL): total active mg in the vial divided by mL of diluent you added.
- Volume to inject (mL): your target dose in mg, divided by the concentration above.
- Insulin-syringe units: a U-100 syringe holds 100 units per 1 mL, so the unit count is volume × 100.
Each peptide has a specific FDA-approved diluent volume on the prescribing information. Using a different volume changes the concentration and therefore the unit count. If your prescription label shows a different number of mL than the FDA label, follow the prescription, your pharmacist made that decision deliberately.
Limitations and important notes
- Most modern FDA-approved peptides ship as pre-filled pens (Wegovy, Ozempic, Mounjaro, Zepbound, Forteo, Tymlos, Saxenda, Trulicity, Vyleesi). For those, follow the pen-specific dial-and-inject instructions, not this calculator.
- Depot suspensions (Lupron Depot, Sandostatin LAR, Trelstar) require specific reconstitution-and-shake procedures from the package insert — read it.
- This calculator assumes a U-100 insulin syringe (100 units per 1 mL). If your prescriber gives you a different syringe (e.g. tuberculin 1 mL, or a 0.5 mL low-dose), the volume in mL still applies but the graduations differ.
- Bacteriostatic water vs sterile water vs the FDA-approved diluent: use exactly what the prescribing information specifies. Substitutions can affect potency and stability.
