What is a Certificate of Analysis (and what it proves)?

What a COA is

A certificate of analysis is a document issued by a laboratory, or sometimes by a manufacturer based on laboratory results, setting out what was tested, how and what was found. In food and supplements, COAs are used to show that a batch meets specifications and legal limits. For shilajit, they are the main evidence buyers can see of what a product contains; see laboratory testing.

What a shilajit COA usually contains

What a COA proves

A COA proves that a named laboratory tested a particular sample, using stated methods, and found the reported results. If the laboratory is accredited for those tests, the results carry assessed competence.^[1] If the batch number matches your jar, the results describe the batch your jar came from.

What a COA doesn’t prove

• That your jar matchesUnless the batch number matches.
• That the right tests were doneThe brand chooses which tests to order.
• That the product worksComposition isn’t evidence of benefit.
• That the document is genuineReports can be edited; verify if in doubt.
• That storage was good after testingResults describe the sample when tested.

See why a COA alone doesn’t prove product quality.

Who issues COAs

Most consumer-facing shilajit COAs are commissioned by the brand from a third-party laboratory. Some come from suppliers, and some brands issue their own summary documents. The laboratory’s own report is the strongest version; see independent vs brand-provided COAs and what “third-party laboratory” tells you.

Why COAs matter so much for shilajit

Shilajit forms in rock and can contain metals, with levels that vary by deposit and batch.^[2] GB law caps lead, cadmium and mercury in supplements,^[3] and the COA is how a buyer can see whether a batch meets those limits. Few supplements depend on batch documentation as heavily; see why contaminant testing matters.

An example COA

Nature Elixirs publishes the AGROLAB LUFA report for batch SJ2509, sample 765188, tested between 25 September and 6 October 2025 by a laboratory stating ISO/IEC 17025 accreditation.^[4] Our team matched a physically received jar to that batch, which is what turns a report into evidence about a specific jar. Nature Elixirs is a brand evaluated by Best Shilajit UK. Read our evaluation to see the evidence and documentation we reviewed.

How to use a COA when buying

1. Get the COA for the batch you’ll receiveSee how to ask.
2. Check the essentialsUse the COA checklist.
3. Compare metals with GB limitsAs sold.
4. Match the batch on arrivalSee batch numbers.

Related terms

You may also see “lab report”, “test report”, “certificate of analysis” or “COA” used interchangeably. A “specification” is different: it lists the limits a product should meet, not results. A “certificate of compliance” may simply state that a product meets requirements without giving results, which is less useful to buyers.

Why COAs became important for shilajit

As shilajit has moved from traditional markets into mainstream online retail, buyers have become more aware of contamination risks. Research highlighting metals in some Ayurvedic products bought online has added to that awareness.^[5] COAs have become the main way responsible brands show what is in their product, and the main way buyers can compare them.

Putting it into practice

Before buying, ask for the COA for the batch you will receive, run through the COA checklist, and match the batch on arrival. Keep the report with your order details until the jar is finished.

COAs for different formats

Capsules, powders, gummies and liquids have COAs too. For blended products, the COA should describe the finished product, including other ingredients, rather than just the shilajit used. Per-serving reporting is more common for these formats, which makes unit conversion important; see units on lab reports.

In short

A COA is evidence about a sample. Matched to your batch and read carefully, it becomes evidence about your jar.

The bottom line

A COA is the laboratory’s record of what it found in a tested sample. It is the most important document a shilajit buyer can see, but it only describes your jar when the batch matches, and only covers the tests that were ordered.

Related reading