The percentage of the peptide-related material in a vial that is the target compound. It says nothing about how much is in the vial, and nothing about safety.

Commonly confused with purity. Potency is about how much active compound is present; purity is about what proportion of the material is the right molecule. A vial can be highly pure and badly underfilled.

How close the measured content is to the amount on the label, measured in both directions. Too little shortchanges the buyer. Too much is a dosing-accuracy failure, not a bonus.

Less active compound in the vial than the label claims.

More active compound in the vial than the label claims. Because dosing is calculated from the label, an overfilled vial delivers a stronger dose than intended on every use.

What the vendor states is in the vial, for example “10 mg”. It is the reference point that measured purity and content results are compared against.

Measured content divided by label claim, expressed as a percentage. A 9.2 mg result on a 10 mg label is 92% recovery.

The mass of actual peptide in a vial, excluding salts, water, and other non-peptide material. Frequently lower than the gross powder weight, and the number that matters.

A certified sample of a known compound that the laboratory compares against. Every identity confirmation is only as good as the standard it was compared to.

The lowest amount an assay can reliably detect. “Not detected” means below this limit, not that the substance is absolutely absent.