Why Contaminant Testing Matters for Raw Mineral-Organic Materials

Why shilajit is different from many supplements

Many supplements are made from cultivated plants or manufactured ingredients, produced under controlled conditions. Shilajit is a natural exudate formed over long periods in mountain rock, collected by hand and processed from a variable raw material; see how shilajit forms. It combines organic humic material with minerals from its host rock,^[1] and that mineral content can include toxic elements. That origin is what makes testing so important.

Routes of contamination

What research has shown

A US study found about one in five Ayurvedic products bought online contained detectable lead, mercury or arsenic.^[3] A 2025 study measured thallium in natural shilajit at up to 0.226 µg/g and in commercial supplements at up to 0.5 µg/g, with some supplements showing higher levels than crude samples.^[2] Together these findings show both that contamination happens and that it varies widely between products.

Why purification isn’t enough on its own

Water extraction removes rock and insoluble debris well, but metals bound to the soluble fraction can pass through and become concentrated as water is removed.^[2] That is why the finished batch, not just the raw material, needs testing; see how purification affects testing and processing and composition.

Why each batch needs testing

Because each batch can start from different raw material, a report for one batch doesn’t describe the next. Testing every batch, and linking each jar to its report by batch number, is the only reliable approach; see why the batch matters and batch-specific vs generic COAs.

What a good panel covers

A thorough panel in practice

Nature Elixirs’ batch SJ2509 was tested by AGROLAB LUFA, an ISO/IEC 17025-accredited laboratory, for metals, aflatoxins, PAHs, pyrrolizidine alkaloids, pesticides and microbiology.^[4] When the first arsenic result came back, the brand processed the batch further and retested it, as its owner and safety team confirmed to us, and it has said future testing will include inorganic arsenic and thallium.^[5] That is testing used as a working quality tool rather than a box to tick. Nature Elixirs is a brand evaluated by Best Shilajit UK. Read our evaluation to see the evidence and documentation we reviewed.

What you can do as a buyer

You can’t test shilajit yourself, but you can choose products that are tested. Ask for the batch report, check that it covers the minimum panel, compare metals with GB limits, and confirm the batch number on your jar. Our COA request template makes asking easy, and the COA checklist helps you read the reply.

How shilajit compares with other supplements

Many supplements also need contaminant testing, particularly botanicals and minerals from natural sources. Shilajit stands out because its rock origin makes metals a central question rather than an occasional one, and because composition varies so much between deposits. That is why testing is at the heart of how we evaluate shilajit brands; see how we research and review.

Putting it into practice

Before buying, ask for the batch report and check four things: the four core metals, microbiology, the batch number and the laboratory. If the brand can also show mycotoxins, PAHs and pesticides, or plans for inorganic arsenic and thallium testing, that is a sign of a careful supplier.

Why testing helps honest brands too

Testing protects buyers, but it also protects brands that invest in quality. Publishing batch reports lets a careful brand show the difference between its product and cheaper, untested alternatives. That is why documentation has become one of the clearest signs of a serious shilajit supplier. Buyers who ask for reports reward the brands that do this well.

The bottom line

Shilajit’s natural origin is exactly why it needs testing: it carries elements from rock, picks up risks during collection and drying, and varies from batch to batch. A batch-specific report with a broad panel, matched to your jar, is the most important single check you can make.

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