Guide

Shilajit and heavy metals — what the testing shows

Shilajit has a documented contamination problem. How to read a certificate of analysis, what these documents leave out, and what to ask before buying.

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The question worth asking first

Before asking whether shilajit does anything, ask what is in the jar. This is one of the few supplement categories where that is a live question with a documented answer, and where the answer varies enormously between products.

Shilajit is a resinous material collected from rock in high mountain ranges. It is not manufactured in the ordinary sense — it is gathered, purified to varying standards, and sold. Material collected from geologically contaminated areas, or purified carelessly, can carry heavy metals. Independent testing organisations have reported contamination in commercially sold shilajit products.

That makes purity the first-order question, and conveniently it is a question that laboratory documents can actually answer — unlike most questions in the supplement aisle.

How to read a certificate of analysis

A certificate of analysis is a laboratory report of what was found in a sample. Most buyers never open one, and the brands that publish them know this.

Look at what was tested for. A COA reports only the analytes it was asked to measure. A document showing clean results for four heavy metals says nothing whatsoever about a fifth that was never on the list. In our view the omissions are usually more informative than the results.

Look for the four that matter. Lead, arsenic, cadmium and mercury. If a report covers fewer than these four, ask why.

Check the sample identity. A useful COA names a specific batch or lot. A document with no lot number cannot be connected to the jar in your hand.

Check the date. A certificate from four years ago describes material sold four years ago.

Check who ran it. An accredited third-party laboratory and the manufacturer’s own quality department are different things. Both are better than nothing; they are not equivalent.

Check the limits used. A result reported as “passes” is only as meaningful as the threshold it passed. Reports that give measured values are far more useful than reports that give verdicts.

What good documentation looks like

The better brands in this category publish a batch-linked certificate from an accredited laboratory, covering at minimum the four heavy metals, with measured values rather than pass or fail, dated within the life of the product on sale.

That is not a high bar. Most of the category does not clear it.

What to ask before buying

1. Where is the material sourced, specifically? A named region beats a continent.
2. Is a certificate of analysis published, and is it linked to a batch?
3. Which analytes were tested, and were measured values reported?
4. Which laboratory ran it, and is it accredited?
5. How recent is the most recent published document?

A brand that answers all five readily has done the work. A brand that answers with marketing copy about ancient traditions has told you something too.

Where we have got to

We are working through the published documentation across brands in this category and will publish the comparison when we have enough to make it fair. In the meantime the product review below covers one brand’s documentation in detail — including what its documents cover, and the significant gap in how it presents them.

We would rather publish one product properly examined than a ranked list assembled from marketing pages.

Written and reviewed by CJ. Last verified 2026-09-03. Next review due 2027-03-03.