Heavy-metal testing for Shilajit

Which metals to test

How metals are measured

The sample is digested in strong acid to break down the organic material, then analysed, most often by ICP-MS, which can measure many elements at very low levels in one run; see ICP-MS explained. Some laboratories use ICP-OES or atomic absorption for certain elements; see laboratory methods. Mercury may be measured by a dedicated method.

What the results should show

• Numerical resultOr “<” a stated limit.
• Unitsmg/kg as sold, ideally.
• Detection or quantification limitWell below the legal maximum.
• Measurement uncertaintyWhere stated.
• Method referenceAnd laboratory accreditation.

Basic vs thorough

A basic test covers the four core metals. A thorough one adds a broader contaminant panel and, increasingly, inorganic arsenic and thallium. Research has measured thallium in shilajit supplements,^[2] and inorganic arsenic is the more toxicologically relevant fraction of arsenic; see arsenic in shilajit.

Test the finished product

Purification can concentrate dissolved metals as water is removed, so tests should be on the finished batch, not just raw material.^[2] See how purification affects testing.

A real example

The AGROLAB LUFA report for Nature Elixirs batch SJ2509 covers lead, cadmium, mercury and total arsenic. It records total arsenic as 0.98 mg/kg in the results table and 0.70 mg/kg in the remarks, with a 55% measurement uncertainty; Nature Elixirs’ owner and safety team confirmed to us that these are successive results, after the batch was processed further to reduce arsenic and retested.^[3] The brand plans to add inorganic arsenic and thallium.^[4] Nature Elixirs is a brand evaluated by Best Shilajit UK. Read our evaluation to see the evidence and documentation we reviewed.

Per-serving reports

Some certificates report metals per serving. A Eurofins certificate published by Nature Elixirs, for example, gives arsenic as 0.213 µg, cadmium as 0.0146 µg and lead as 0.0367 µg per 0.5 mL serving.^[5] Per-serving figures can’t be compared with mg/kg limits without the serving’s weight and basis; see units on lab reports.

Sampling for metals testing

A representative sample of the finished, well-mixed batch should be sent for testing, in a quantity specified by the laboratory. The AGROLAB report for batch SJ2509 records a 300 g sample.^[3] Good sampling helps ensure the result reflects the whole batch rather than one corner of it; see variation between samples.

How often metals should be tested

Every batch, ideally, because metal levels depend on the raw material, which can change between batches. A single historic metals report can’t vouch for current stock; see batch-specific vs generic.

Interpreting results near a limit

A result close to a GB limit deserves attention, because measurement uncertainty means the true value could be slightly higher. Consistent results well below the limits are the better long-term sign; see heavy-metal limits.

Accreditation for metals

Check that the laboratory states ISO/IEC 17025 accreditation, ideally covering the metals methods used.^[6] Accreditation shows the laboratory has been assessed for competence in those methods; see lab accreditation.

Putting it into practice

When you receive a metals report, check that all four core metals are present, in mg/kg as sold, with detection limits well below the GB maximums, and that the batch matches your jar. Note whether inorganic arsenic or thallium were tested. If any of these are missing, ask the brand, using our COA request template.

In short

Four core metals, the finished batch, mg/kg as sold, stated limits, and a matching batch number.

Why metals testing is non-negotiable

Because shilajit forms in rock, metals testing isn’t an optional extra; it is the core of shilajit safety. A brand that can’t show recent metals results for the batch you are buying hasn’t answered the most important question about its product, however good its marketing looks. Asking for those results is the single most useful question a buyer can put to any shilajit brand. Treat missing metals results as a reason to pause before buying, however appealing the product looks. Ask before you buy.

The bottom line

Good heavy-metal testing covers the four core metals on the finished batch, reports numbers in mg/kg with detection limits, and is compared with GB limits. Inorganic arsenic and thallium testing go beyond the standard and are a strong sign of care.

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