Shilajit Laboratory Testing

Why shilajit needs testing

Shilajit is a natural material scraped from rock, its composition changes from deposit to deposit, and visual checks can’t reveal what it contains. Three things follow. Its identity has to be confirmed analytically. Its contaminant levels have to be measured, because metals in the source rock can carry through into the product. And every batch can differ, so a test from last year’s harvest says little about this year’s jar.

The risk is not theoretical. A 2025 study found measurable thallium in both raw shilajit and finished supplements, with some supplements higher than the raw samples.^[1] In Great Britain, food supplements must not exceed legal maximum levels for lead, cadmium and mercury as sold.^[2] Testing is how a seller shows that a batch meets them. See why contaminant testing matters for mineral-organic materials.

Certificates of Analysis and batch evidence

A Certificate of Analysis (COA) is the report a laboratory issues after testing a sample. It should identify the sample, the tests, the methods, the results and the date. What it proves is limited to that sample, which is why the link between the sample and the product on sale matters so much.

Read more on what a COA is and what it proves, batch numbers and testing dates, batch-specific vs generic COAs and why a COA alone doesn’t prove quality.

In-house, third-party and independent testing

“Third-party tested” means a laboratory outside the brand did the work, but the brand usually chose the lab, chose the sample and chose whether to publish. That is different from testing commissioned by someone with no stake in the result, such as a consumer organisation buying products off the shelf. Both have value; they answer different questions. See what “third-party laboratory” tells you and independent testing vs brand COAs.

Laboratory accreditation: ISO/IEC 17025 and UKAS

ISO/IEC 17025 is the international standard setting out requirements for the competence, impartiality and consistent operation of testing and calibration laboratories.^[3] In the UK, accreditation against it is granted by UKAS, the country’s sole national accreditation body.^[4]

Two details often get missed. First, accreditation applies to specific tests listed on a lab’s schedule of accreditation, not to everything the lab does. A lab accredited for lead in food may not be accredited for fulvic acid. Second, accreditation tells you the lab is competent; it says nothing about whether the product passed. Accredited labs outside the UK are assessed by their own national bodies. See lab accreditation explained and laboratories that appear on UK brand COAs.

Test methods you’ll see on a COA

The method determines what a result can tell you. The same element measured by two methods can have very different detection limits.

What should be tested

Units, detection limits and “not detected”

Metal results are reported as concentrations. The units look different but several are identical.

Limit of detection (LOD) is the lowest level a method can reliably detect; limit of quantification (LOQ) is the lowest it can measure with acceptable accuracy. “Not detected” means below the LOD for that method, not zero. A “not detected” result with a high detection limit can hide a level you would want to know about, which is why the limit should be printed next to the result. See units on lab reports, detection limits and what “not detected” means.

Fulvic acid results don’t compare

Fulvic acid percentages are the most marketed number in shilajit, and the least comparable. Different laboratories use different extraction and measurement methods, some of which also capture other substances. A 60% result from one method and a 75% result from another may describe similar material. Without the method named, a fulvic acid figure is close to meaningless, and a higher figure is not automatically better. See why fulvic acid percentages don’t compare and can more fulvic acid mean better shilajit?

COA red flags

• No laboratory name or contact detailsYou can’t verify a report from an anonymous source.
• Batch number missing or doesn’t matchThe report may relate to a different product or year.
• “Pass” without numbersPass against what limit? Measured how?
• Only fulvic acid and minerals reportedNo contaminant data means no safety information.
• Detection limits missing“Not detected” can’t be interpreted without them.
• Old or undated reportTesting should be recent and match current stock.
• Edited-looking documentsMismatched fonts, cropped headers or missing pages. Ask the lab to confirm.

The full list, with examples, is on red flags in a shilajit lab report. Use the interactive COA checklist to score a report you have.

How we use laboratory evidence

When we evaluate a product, we record whether each document was supplied by the brand or commissioned independently, and we label it accordingly. Brand-supplied COAs are reviewed for completeness and consistency; they are not treated as independent verification. Where we commission our own tests, the laboratory, method and full results are published with the review. The programme and its status are described on our independent test programme and independent lab-testing methodology.

Worked example: reading a brand’s published reports

Nature Elixirs publishes three laboratory documents, and together they show most of the reading skills on this page in practice. An AGROLAB LUFA report for batch SJ2509 covers metals, mycotoxins, pesticides and microbiology from a laboratory stating ISO/IEC 17025 accreditation.^[5] It records total arsenic with two figures (0.98 mg/kg in the results table and 0.70 mg/kg in the remarks) and a stated 55% measurement uncertainty, and the laboratory recommends determining inorganic arsenic, the toxicologically relevant fraction. A Eurofins certificate reports metals per 0.5 mL serving, a basis that can’t be compared directly with mg/kg.^[6] An IAS composition report relates to an earlier sample, not batch SJ2509.^[7] We walk through each one in the Nature Elixirs evaluation.