Reconstitution Mix Checker
Vial amount, water volume, target dose, and CoA purity — get the corrected draw on a U-100 syringe. The NPC adjustment formula is shown.
0% = pure as labeled. 10% means 10% of the vial weight is non-peptide (e.g. salts, moisture), so the actual peptide concentration is 90% of nominal.
10 mg in 2 mL of BAC water
500 mcg → 0.1 mL → 10 units
Draw to the 10-unit mark on your U-100 syringe.
Research use only — not medical advice. NPC (Net Peptide Content) is read from a Certificate of Analysis (CoA) supplied by the manufacturer. mg vs mcg: 1 mg = 1,000 mcg; mixing them up is a thousand-fold error. Always double-check the unit label before drawing.
Understanding Net Peptide Content
When a manufacturer produces a lyophilized (freeze-dried) peptide vial, the powder inside is almost never 100% peptide. It contains counter-ions (acetate, TFA), residual moisture, and other non-peptide material. The Certificate of Analysis (CoA) that ships with the vial reports this as either a purity percentage or an NPC (non-peptide content) percentage.
The math is straightforward: if a vial is labeled 10 mg but the CoA says 90% purity (10% NPC), the actual peptide content is 9 mg. If you add 2 mL of bacteriostatic water, the nominal concentration would be 5,000 mcg/mL, but the effective concentration is only 4,500 mcg/mL. For a 500 mcg dose, you would need to draw 0.111 mL instead of 0.100 mL — a small but meaningful difference at low doses.
Common questions
What is NPC (Net Peptide Content)?
NPC is the percentage of a vial’s contents that is not the peptide itself — it includes counter-ions, residual solvents, moisture, and other non-peptide matter. A CoA might state 85% purity, which means 15% NPC. The higher the NPC, the less actual peptide per mg of vial content, so the more volume you need to draw for the same dose.
Where do I find the NPC?
On the Certificate of Analysis (CoA) supplied by the manufacturer. Look for Net Peptide Content, purity, or assay. If it lists purity (e.g. 92%), the NPC is 100% minus purity (8%). If it lists NPC directly, use that number.
How does NPC change my draw?
If the vial is 10% non-peptide (NPC = 10%), the effective concentration is 90% of what the label says. To get the same dose, you need to draw about 11% more volume. The formula: effective concentration = nominal concentration × (1 − NPC/100).