Guides / Why batch numbers matter
Why the batch number on a lab report matters
Updated 4 November 2026 · BatchAssay editorial
In short
- Contamination lives in the raw material, and raw material changes with every batch — so test results only apply to the batch that was tested.
- A COA without a batch number cannot be matched to any product on a shelf; it is a marketing document, not evidence.
- The strongest signal a brand can send: a per-batch lookup where you enter the number on your own jar.
One product, many batches
The jar design stays the same for years; what is inside it does not. Every production run starts from new raw material — a different ashwagandha harvest, a new lot of creatine from the supplier, another catch of anchovies. Heavy metals, mycotoxins and microbiological contamination all come in with that raw material. A batch tested clean in March says nothing about the batch produced in September from a different field.
This is why "our product is lab tested" is an incomplete sentence. The honest questions are: which batch, by whom, when, and where can I see it?
Matching a report to your jar
Find the batch or lot number on your product (near the expiry date; often prefixed LOT, L, CH or Batch) and compare it to the number on the report. An exact match means the lab measured the same production run you are holding. On every verified BatchAssay product page the batch number is shown next to the verdict for exactly this purpose — and when the published report is for an older batch than current stock, that is worth knowing too.
What we accept, and what we don't
- Accepted: a report from an accredited lab naming a specific batch/lot, recent enough to be current (~18 months).
- Not accepted: reports without a batch number; "representative sample" reports; raw-ingredient certificates from a supplier that say nothing about the finished product; expired reports.
- Gold standard: brands that publish a report for every batch, searchable by the number on the jar.
FAQ
Where do I find the batch number on my supplement?
Usually printed or laser-etched near the expiry date — on the bottom of the jar, the crimp of a pouch, or the side of the label. It is often prefixed LOT, L, CH (Charge, German) or Batch.
The published report is for a different batch than mine. Is it useless?
Not useless — it proves the brand routinely tests and publishes, which most don't. But it is evidence about that batch, not yours. Brands with per-batch portals let you look up your own number; that is the gold standard.
Why would contamination differ between batches of the same product?
Because the raw material changes: a different harvest, field, ocean catch or supplier lot. Heavy metals come in with the raw material, so each new batch is a new roll of the dice unless it is tested.
Does BatchAssay accept reports without a batch number?
No. A missing batch number is a hard fail in our checks — the report may be genuine, but it cannot be matched to any product you can buy, so it verifies nothing.
Sources
- Regulation (EU) 2023/915 — contaminant limits apply per product as sold, batch by batch
- ISO/IEC 17025 — sample identification requirements for accredited test reports
- BatchAssay methodology — batch matching as a hard verification check
Information only, not medical advice. Methodology