Everything you need to know
You know only what a laboratory measured on the vial you submitted. Identity asks whether the compound matches the name. Content asks how many milligrams are in that vial. Purity alone cannot confirm the label fill.
How do I know my peptide vial has what the label says?
Only by having the vial measured. A label is a claim, and a certificate is a measurement of one sample. Matching the two takes three results on material you control: identity, which confirms the named peptide is present; purity, which reports how much of the peptide signal is the intended compound; and content, which reports how many milligrams are in the vial against a characterised reference standard. If the label states a milligram amount and the certificate has no content figure, the claim that matters for dose has not been tested.
Why is a high purity percentage not enough?
Purity is a ratio from chromatography, and it does not weigh the vial. A vial can be 99% pure and still hold fewer milligrams than the label states. In the largest published analysis of third-party peptide reports, 32.8% of samples met the purity criterion but fell outside the acceptable range for amount, against 3.0% the other way (Mendias and Awan, doi:10.20944/preprints202604.1748.v1; a preprint, and not a Prodigy study). More on purity versus content.
Does testing one vial prove the rest of the kit?
No. One certificate describes the vial that was used up in testing. Batch or lot numbers help you track which kit a vial came from, but they do not make untested vials measured. More on what one tested vial covers.
Can I check a vial at home?
Not for identity, purity or milligram content. Appearance, how the powder dissolves and a vendor PDF do not measure what is in the vial in your hand. Those questions need chromatography against a reference standard.
What should I send to the lab?
Send an intact, unopened vial with its identifiers: the vendor, the lot or batch number if there is one, the claimed peptide and the claimed strength. How much material a lab needs. At Prodigy Labs, Tier 1 Confirmed + Content ($295) is the first published package that reports content in mg per vial. Basic ($195) reports purity and retention-time identity only.
Is this medical advice?
No. This is analytical guidance about testing research peptides. It is not medical advice, and it is not a statement that any product is approved or suitable for use in people.