Batch-specific vs catalog COAs

A batch-specific COA is a certificate of analysis that documents a specific production batch. It carries a lot number or batch identifier, a testing date, and results that apply to that lot alone. When a vendor tests every batch and publishes a distinct COA for each, you can trace the vial you receive back to the test that documented it.

A catalog or historical COA is a single certificate that a vendor publishes once and presents as representative of an entire product line. It may carry no lot number, no date, or a date from months or years ago. It is reused across multiple products, batches, or time periods without being updated. The vendor is saying: "we tested this compound at some point, and we expect all future batches to be similar."

Both documents can be genuine. Both can report accurate results. But they answer different questions, and only one of them lets you verify that the vial in your hand came from the batch that was tested.

A COA without a lot number cannot be traced to a production run. A COA without a date cannot be placed in time. A COA reused across multiple products cannot distinguish between them. Each missing piece of traceability reduces what the document can establish:

• No lot number: the results apply to some batch, but you cannot confirm which one. If the vendor produces a new batch next month, this certificate tells you nothing about it.
• No date: the testing could have been done last week or three years ago. Production conditions change. A test from two years ago does not reflect current manufacturing, and it cannot confirm ongoing quality.
• Reused across products: if the same PDF appears on five different product pages, at least four of those products are documented by a test that was not performed on them. The certificate is evidence about one product being used as evidence about five.

This is why we treat a single undated, un-lotted PDF as weaker evidence than a set of dated, lot-specific certificates — even if the single PDF reports excellent results. The issue is not that the results are wrong; it is that they cannot be tied to the product you would receive.

Check the vendor's product pages or COA directory for the following signals:

• Lot numbers that match the product listing. If the product page says "Lot #12345" and the COA says "Lot #12345," the document is batch-specific. If the COA has no lot number or a different one, it is not.
• Multiple distinct COAs for the same compound. If a vendor has three COAs for BPC-157, each with a different lot number and date, they are testing per batch. If they have one COA for BPC-157 that appears on every BPC-157 product page, it is a catalog certificate.
• Recent dates. A COA dated within the last 6-12 months is more likely to reflect current production. A COA from two years ago, or with no date at all, is historical.
• Unique documents per compound. If every compound on the vendor's site links to a different PDF with a different lab report, the vendor is documenting each product. If many compounds link to the same PDF, it is a reused certificate.

The Batch Integrity subscore (0-20 points within the Purity & Testing category) directly measures whether a vendor provides batch-specific documentation:

• Full marks (18-20) — the vendor tests and publishes a distinct COA for every production batch, with lot numbers and dates that match the product listings.
• Partial credit (10-17) — the vendor provides some batch-specific COAs but not for every product, or the documentation is inconsistent across the catalog.
• Low credit (5-9) — the vendor provides a single representative COA per compound, without lot numbers or with reused documents.
• Minimal credit (0-4) — the vendor provides undated, un-lotted PDFs that are reused across multiple products.

The COA Freshness subscore (0-10 points) is also affected. An undated certificate cannot earn freshness credit because its age is unknown. A dated certificate from two years ago earns less than one from last month. See the scoring methodology guide for the exact calculation.

Our internal review process, described in how PeptideScores verifies a COA, includes reused-report detection and lot mismatch checks that identify catalog certificates being presented as batch-specific evidence.

A vendor with strong batch integrity will have:

• A distinct COA for each lot of each compound, with lot numbers visible on both the product page and the certificate
• Dated reports, with the most recent COA within the last 6-12 months
• Multiple COAs per compound over time, showing ongoing testing rather than a one-time effort
• No reused PDFs across different products or batches
• Testing from an independent laboratory, not an in-house or affiliated facility

Few vendors meet every one of these criteria across their entire catalog. The vendors that come closest are the ones that score highest in the Purity & Testing category, and by extension in the composite score, because Purity & Testing carries 35% of the total weight.