When you buy a "5mg" vial, you assume there is 5mg of active peptide inside. However, in analytical chemistry, it's more complex. This affects mcg vs mg conversion.
Gross Weight vs. Net Content
The lyophilized powder in the vial is not 100% peptide molecules. It typically contains:
- Peptide: The active amino acid chain.
- Counter-ions: Salts like Acetate or Trifluoroacetate (TFA) that stabilize the molecule.
- Residual Water: Even freeze-dried products hold some moisture.
The Certificate of Analysis (CoA)
A high-quality vendor will provide a CoA. Look for "Net Peptide Content" (often ~80%) and "Purity" (often >98%).
Purity means "of the peptide chains present, 98% are the correct sequence."
Net Content means "80% of the powder weight is peptide, the rest is salt/water."
For standard research, we usually calculate based on the label weight (5mg), but technically, the active dose might be slightly lower. This nuances how to calculate peptide concentration.
Use the ultimate reconstitution calculator for your baseline math, but be aware of these variances. If mixing, check peptide mixing calculator.