What is a certificate of analysis (COA)?
A certificate of analysis (COA) is a lab report that documents the tested properties of a specific product batch: active content, contaminants and purity. It shows whether a product actually contains what the label says.
Certificate of analysis explained simply
The COA summarises what a laboratory measured on a specific batch – including method, measured value and limit. It may also be called lab certificate or test report. For supplements and plant extracts it is a central quality document, because raw material varies: cultivation, harvest year and processing affect content and contamination.
What does a COA typically contain?
- Identity and content: How much of the active compound is present? In turmeric extracts these are the curcuminoids, usually determined by HPLC.
- Contaminants: Testing for heavy metals such as lead, cadmium, mercury and arsenic, and depending on the product for pesticides and mycotoxins.
- Microbiology: Total counts, yeasts and moulds.
- Residual solvents: Relevant if extraction solvents were used.
- Batch number and date: Only these allow the certificate to be matched to a product.
What makes a COA meaningful
A short checklist
| Feature | Why it matters |
|---|---|
| Feature Batch number matches the packaging | Why it matters Shows that exactly this product was tested |
| Feature Method stated (e.g. HPLC) | Why it matters Makes the measured value traceable |
| Feature Measured value next to limit | Why it matters Shows how far below the limit the value is |
| Feature Independent or accredited laboratory | Why it matters Increases reliability |
| Feature Date and signature | Why it matters Shows currency and accountability |
Why this matters for turmeric
With turmeric powder and cheap raw goods, contamination is hard to judge, and impurities have been reported in individual cases. Purified and standardised extracts with an accessible certificate of analysis are more transparent here. A COA is a quality proof, not proof of efficacy. It says something about content and purity, not about whether a product helps with any complaint.
For Curcumin+, every batch is tested by HPLC and the batch-specific certificate is available.
How to check one
Ask the manufacturer for the COA matching the batch number on your pack. Compare the stated content with the product claim and check that limits are given. A generic, undated certificate without a batch is less meaningful. Be wary if measured values look suspiciously round or are identical for every batch.
Frequently asked questions
Must a manufacturer publish its COA? There is no general obligation for food supplements. Reputable manufacturers still provide it or show it on request.
Is a COA from the raw-material supplier enough? It is a start. Testing the finished product is more meaningful, because processing and filling can change content.
What does “below the limit of detection” mean? The substance was not found with the method used or is too low to be measured reliably. It does not automatically mean zero.
