Shilajit certificate of analysis: how to read

A certificate of analysis (COA) is the most useful document a shilajit seller can give you: the only practical way to know whether the jar contains real shilajit and whether its heavy metal and microbe levels are safe. It’s also easy to misread, because labs use different units, methods and standards for what counts as a “pass”.

This guide goes through a typical COA from top to bottom. Compare each figure with the UK limits rather than whatever standard the report chose. If a seller won’t send a COA, that alone is a reason not to buy; see the buying guide.

What should the top of a certificate of analysis show?

The header should identify the lab, the product and the batch, and every one of these should check out.

• Lab name, address and accreditation number. The lab should be independent of the seller.
• Accreditation to ISO/IEC 17025, the international standard for the competence of testing and calibration labs. In the UK, labs are accredited by UKAS (the UK Accreditation Service), which the government appoints as the UK’s sole national accreditation body. UKAS publishes a list of the organisations it accredits. Overseas labs may be accredited by a body in their own country; UK government guidance refers to the multilateral agreements UKAS has with accreditation bodies in other countries.
• Scope. Accreditation covers specific tests, not everything a lab does. Check that the methods on your certificate are on the lab’s accreditation schedule.
• Product name and batch or lot number. The batch number must match the one printed on your jar or box. A certificate for a different batch tells you nothing about yours.
• Dates: when the sample was received, when it was tested, and when the report was issued.
• Signature by a named person at the lab.

Be careful not to confuse ISO/IEC 17025 with ISO 9001. ISO 9001 certifies a company’s quality management system; it doesn’t show that a lab’s test results are reliable.

How do I read the heavy metal results?

Look for a number, a unit and a method for each of lead, cadmium, mercury and arsenic, then compare each number with the GB limit.

These limits come from the contaminants regulation as it applies in Great Britain, and they apply to the food supplement as sold (Regulation 1881/2006, Annex). That last point matters: a result reported “on a dry weight basis” or for an ingredient rather than the finished product isn’t directly comparable.

There’s no GB limit for arsenic in supplements; the regulation only sets inorganic arsenic limits for rice and rice products. That doesn’t make arsenic harmless. Look for a low figure and ask the seller what limit they work to. If the certificate separates total from inorganic arsenic, note the inorganic figure: that’s the form GB law limits in rice, and generally the form of most concern.

How do I convert ppm, ppb, mg/kg and µg/g?

Labs report the same quantity in several ways. These are all equal:

1 mg/kg = 1 ppm = 1 µg/g = 1,000 µg/kg = 1,000 ppb

To work out how much of a metal you’d swallow each day, multiply the result in mg/kg by your daily dose in grams. The answer is in micrograms. For example, lead at 0.42 mg/kg and a 0.5 g daily dose gives 0.21 micrograms of lead a day.

What do ND, LOD and LOQ mean?

They describe the smallest amount the lab’s method can see or measure. The limit of detection (LOD) is the lowest level it can detect; the limit of quantification (LOQ) is the lowest it can measure with confidence.

“ND” (not detected) or “<LOQ” is good news only if the limit is stated and sits well below the legal maximum. “ND” with no limit given could hide a level that a more sensitive test would have measured.

A “pass” against which standard?

Some certificates mark results “pass” or “complies” against a standard other than UK law. A 2024 review of shilajit metals quoted World Health Organization and US limits for herbal products of 10 ppm for lead and arsenic, 1 ppm for mercury and 0.2 to 0.3 ppm for cadmium (Hussain and Saeed, 2024). The lead and mercury figures are far looser than the GB supplement limits of 3.0 and 0.10 mg/kg. A product could “pass” on its certificate and still be over the UK limit, so always compare the number yourself.

Other metals sometimes appear. Thallium, for instance, has been measured at up to 0.5 µg/g in shilajit supplements (Kamgar et al., 2025). The GB contaminants regulation doesn’t set a thallium limit, so judge such results with care rather than assuming they’re fine.

What microbial tests should a shilajit certificate include?

Look for counts of total bacteria (often called total aerobic microbial count or total plate count), yeasts and moulds, usually in colony-forming units per gram (cfu/g), and tests for specific harmful bacteria such as E. coli and Salmonella, often reported as “absent” in a stated weight such as 10 g or 25 g.

There are no GB legal microbiological criteria written specifically for food supplements: the microbiological criteria regulation lists other food categories but not supplements (Regulation 2073/2005, Annex I). Instead, the general rule applies that food must not be placed on the market if it is unsafe (Regulation 178/2002, Article 14). It’s reasonable to expect Salmonella and E. coli to be absent, and the certificate should say which reference limits the lab used for the counts.

How should fulvic acid be reported?

As a percentage with the test method named, because different methods measure different things. A standardised gravimetric method exists that separates humic and fulvic acids and weighs them on an ash-free basis; it was developed for humic ores and commercial humic products rather than for shilajit specifically (Lamar et al., 2014). Researchers studying shilajit have also used gravimetric analysis for total fulvic acid, alongside chromatography to measure individual marker compounds (Kohli et al., 2026).

For reference, the extract in one strength trial was standardised to at least 50% fulvic acid plus 10% dibenzo-alpha-pyrones (Keller et al., 2019), and the resin in another was standardised to at least 60% fulvic acids (Yadav et al., 2026). Only compare percentages between products if the method is the same. A figure with no method is close to meaningless.

What other tests might appear?

You may see results for:

• Polycyclic aromatic hydrocarbons (PAHs). GB limits for food supplements containing botanicals are 10 µg/kg for benzo(a)pyrene and 50 µg/kg for the sum of four PAHs. The definition of botanical preparations covers plant-derived materials including “processed exudates”; whether shilajit falls under it is not clear.
• Pesticides and aflatoxins, which the resin in one trial was tested for (Yadav et al., 2026).
• Identity tests, such as chromatographic fingerprints. See fake shilajit.

What does a good certificate look like?

The example below is made up to show the format. It isn’t from any real product or lab.

If yours has numbers, units and methods for each line, a batch number that matches your jar, and an accredited lab you can look up, it’s doing its job. If you’re unsure whether a certificate is genuine, contact the lab directly and quote the report number.

For what the limits mean for your health, see shilajit and heavy metals, and for the law behind them, is shilajit legal in the UK?.