Is a supplier COA enough for a retailer?

Usually not. A supplier COA normally covers the raw material or an earlier batch. Most retail and marketplace checks ask for independent testing of the finished product.

How long is a COA valid?

A COA describes one batch at one point in time. It does not expire, but buyers expect a document that matches the batch on sale, plus stability data to back up the shelf life claim.

Do I need an ISO 17025 lab?

For anything you plan to show a retailer, yes. Accreditation is what makes the result defensible if it is ever challenged.

How to read a supplement certificate of analysis

Updated 16/09/2026

A certificate of analysis is the document a retailer, marketplace or auditor asks for when they want proof of what is in your product. Here is what each part means and where most COAs fall short.

Key points

A COA is only as strong as the lab behind it: look for an ISO 17025 accreditation number.
Every result needs a method reference, a limit and a measurement uncertainty.
The COA must name the batch, not just the product.
A supplier COA covers the raw material. Retailers usually want the finished product tested.

The header: who tested what

The top block identifies the lab, the sample and the batch. If the batch or lot number is missing, the document cannot be tied to the stock sitting in your warehouse, which is the first thing an auditor checks.

The lab should state its accreditation. ISO 17025 means an external body has confirmed the lab is competent for the specific methods it runs, not just that it exists.

Lab name, address and accreditation number
Product name, batch or lot number, sample receipt date
Date of analysis and date of report

The results table

Each row should carry four things: the parameter, the result, the unit and the method. A result without a method is not verifiable, because two methods for the same parameter can have very different detection limits.

Watch for the reporting limit. A result of "< 0.01 mg/kg" only means the lab could not detect anything down to 0.01. If the legal limit is lower than the reporting limit, the test has not actually proven compliance.

Parameter, result, unit, method reference
Specification or legal limit used for the pass or fail call
Measurement uncertainty for quantitative results

Where COAs usually fail a retail review

The most common problem is scope. A COA from your contract manufacturer often covers the raw material or an older batch, and the parameters chosen were the ones cheap to run, not the ones the retailer cares about.

The second problem is age. Buyers want a document tied to a batch currently on the market, and stability data if the shelf life claim on the label is long.

What we deliver

Test My Batch runs the finished product through accredited partner labs and returns a certificate of analysis with methods, results, EU limits and uncertainty values, in a format major EU retailers already accept. Every report stays available in your portal, so you can forward a link instead of digging through email.

Questions

Is a supplier COA enough for a retailer?: Usually not. A supplier COA normally covers the raw material or an earlier batch. Most retail and marketplace checks ask for independent testing of the finished product.
How long is a COA valid?: A COA describes one batch at one point in time. It does not expire, but buyers expect a document that matches the batch on sale, plus stability data to back up the shelf life claim.
Do I need an ISO 17025 lab?: For anything you plan to show a retailer, yes. Accreditation is what makes the result defensible if it is ever challenged.