How many units do I draw for a peptide dose?
Units depend on three numbers: how many mg are in the vial, how many mL of BAC water you added, and how many mcg you want per dose. On a U-100 insulin syringe, 100 units equals 1 mL, so the unit number is just the dose volume converted to syringe units.
The formula
- Vial mg x 1,000 = total mcg in the vial.
- Total mcg divided by BAC water mL = mcg per mL.
- Target dose mcg divided by mcg per mL = mL per dose.
- mL per dose x 100 = insulin syringe units.
Example
A 5 mg vial mixed with 2 mL BAC water has 2,500 mcg per mL. A 250 mcg dose is 0.1 mL. On a U-100 insulin syringe, 0.1 mL is 10 units.
Common beginner mistake
Do not read mg on the vial as the dose. A 5 mg vial contains 5,000 mcg total. The dose is usually a smaller amount drawn from that mixed vial.
Pepdex is an educational reference, not medical advice. Peptides vary in legal, approval, and evidence status. This answer is meant to explain the concept, not prescribe a protocol or replace a qualified clinician.
Helpful next pages
More dose math answers
Last updated 2026-07-07.