Lot Number
A lot number is a code stamped on each batch of a product so that batch can be traced back to when and how it was made — and matched to its test results.
Where the word comes from
“Lot” is an old Germanic word: Old English hlot, an object drawn from a container to make a fair choice — the same word as in “casting lots.” From “a share decided by drawing” it came to mean a portion of goods, and then a batch of product made together in one run. “Number” is from Latin numerus. Stamping each batch with its own code is a factory quality-control practice from the 1900s: it lets any single unit be traced back to its production records.
What it means here
Peptides are made in batches, and quality can differ from one batch to the next. The lot number ties a specific vial to the certificate of analysis for its batch, so a researcher can confirm that the exact batch in hand was tested for purity and identity. A product with no lot number cannot be matched to any test result, which is why the lot number is one of the first things a careful buyer looks for on a label.
Words you’ll see together
- certificate of analysis — the test report a lot number matches a vial to
- batch — the group of vials made together that shares one lot number
- lot-specific — a label meaning a result applies only to that one batch
- third-party testing — testing done by an outside lab, reported per lot
- purity — the headline number reported for each lot
Related terms
- Certificate of Analysis — the test report a lot number points to
- Purity — the main measurement reported per lot
- Stability — batch records also track how a lot holds up over time
Where it appears in our catalog
- Certificates of Analysis FAQ — how lots and COAs match up
- How to read a certificate of analysis — finding the lot number on a real COA
- Choosing a supplier — why lot-level traceability matters when comparing vendors
