Home › Learn › Questions › Buying
How many mg should be in my peptide vial?
The short answer
What the label claims — measured as peptide, not as powder. A vial labelled 5 mg should contain 5 mg of peptide, and public community datasets commonly treat deviations beyond about ten percent as failures. Because counter-ion and moisture add weight, a vial filled to 5 mg of powder will normally hold measurably less peptide than that.
In detail
This is the most consequential number on a certificate for most buyers, and the one that fails most often in practice.
Direction matters as well as magnitude. Consistent under-fill across a lot points at the filling process; scatter between vials of the same lot points at process control.
Testing several vials from one lot answers a different question than testing one vial from several lots, and it is worth deciding which question you are asking before you ship.
Related questions
People also ask
Iberian Analytical opens in Q1 2027 — €99 per test, 48–72 h target, and every result published in a public database, mandatory and free. Nothing is sold on this site today. Leave an email and we will write once, when the laboratory starts issuing certificates.
Have a question that is not here? Write to [email protected] — we answer in public, and every real question becomes a page.