Published by Peptide Protocols · Reviewed September 2026 · How we make these pages · Educational & research purposes only — not medical advice.
1 mL = 100 units on a U-100 insulin syringe. Formula: mg ÷ mL = mg/mL; (mcg ÷ 1000) ÷ mg/mL = mL; mL × 100 = units.
Units to draw on a U-100 insulin syringe for the common vial sizes and water volumes. Pick the row that matches your vial and the water you added.
| Vial + water | Concentration | 2 mg | 2.5 mg |
|---|---|---|---|
| 5 mg vial + 1 mL water | 5 mg/mL | 40 u | 50 u |
| 5 mg vial + 2 mL water | 2.5 mg/mL | 80 u | 100 u |
| 5 mg vial + 3 mL water | 1.66667 mg/mL | 120 u | 150 u |
| 10 mg vial + 1 mL water | 10 mg/mL | 20 u | 25 u |
| 10 mg vial + 2 mL water | 5 mg/mL | 40 u | 50 u |
| 10 mg vial + 3 mL water | 3.33333 mg/mL | 60 u | 75 u |
Worked example: a 5 mg vial with 2 mL of bacteriostatic water is 2.5 mg/mL. A 2 mg draw is 0.80 mL, which is 80 units. Change the water and every number on the syringe changes — which is the single most common reconstitution mistake. The full explanation is in How to Reconstitute Peptides.
A 5 mg vial with 2 mL of water is 2.5 mg/mL, so 2 mg = 0.8 mL = 80 units. That is most of a syringe, which is why many researchers use 1 mL of water (5 mg/mL) so the same 2 mg is 40 units.
Yes, by total mg. There is a dedicated BPC-157 / TB-500 blend calculator for the 10 mg and 20 mg blend vials.
We do not recommend or partner with any peptide supplier. Use the checklist instead: third-party COAs that match your batch and lot, stated purity, clear research-use labeling, real support and proper cold-chain shipping.
The supplier checklist →Educational content only. Confirm the legal status where you live before ordering anything.
The one formula, a BAC-water chart, and the 10 most-researched beginner peptides — the math done for you. Print it for the fridge.
🎁 Send me the free cheat sheet →Every cheat sheet in the shop includes the Universal Excel Logbook — it auto-calculates reconstitution and tick marks for 38+ peptides and keeps a dated record of each vial.
Browse the cheat sheets on Etsy →