Heavy metals in shilajit: the contamination risk brands don’t advertise

If you take one thing from any shilajit page, make it this one. The best-documented fact about shilajit is not a benefit, it is a risk: because the raw material concentrates whatever sits in its host rock, unpurified resin can carry toxic heavy metals. This guide lays out exactly what has been measured, why a purified label is not automatic safety, and what to demand before you buy.

Why raw shilajit concentrates metals

The same chemistry that makes shilajit interesting is what makes raw resin risky. Fulvic acid, its active fraction, binds cationic metals. That is useful for the material’s proposed biology, but it also means the resin accumulates whatever toxic cationic metals are present in the rock over geological time. Raw, unpurified shilajit is therefore not fit for human consumption before processing.

Raw unpurified shilajit can concentrate toxic heavy metals such as lead, arsenic, mercury and cadmium because the material accumulates whatever is present in its host rock over geological time. [Stohs 2014] Moderate evidence

What contamination testing has actually found

Shilajit sits inside the broader Ayurvedic supplement category, and that category has been studied at scale. The findings are not reassuring. A landmark analysis of Ayurvedic medicines sold online found metals in a large share of products.

A landmark analysis of US and Indian Ayurvedic medicines sold online found roughly one in five contained detectable lead, mercury or arsenic, and every contaminated product taken as directed could exceed regulatory daily intake limits. [Saper 2008, JAMA] Strong evidence

That category-level harm is not hypothetical. Documented human heavy-metal poisonings from Ayurvedic and herbal products have prompted regulator action, including a formal warning about heavy-metal poisoning tied to certain unapproved Ayurvedic drug products.

US regulators have warned that consuming certain unapproved Ayurvedic drug products would likely be injurious because of mercury and lead exposure, after documented poisonings. [FDA heavy-metal warning] Strong evidence

The thallium finding brands rarely mention

Most coverage stops at lead, arsenic, mercury, and cadmium. A 2025 analysis added a metal that almost never appears in consumer articles: thallium, which is more toxic than lead, cadmium, or mercury. It was measurable in raw shilajit, and here is the part that undercuts the whole marketing story: some finished supplements contained more thallium than the crude material did.

Thallium, a metal more toxic than lead, cadmium or mercury, was measured in both raw shilajit and finished supplements, and some supplements contained more thallium than the crude material. [Kamgar 2025, BMC Chemistry] Moderate evidence

The study authors called for routine standardised testing precisely because processing did not ensure a lower metal load. That is the single most important nuance on this whole topic: purified does not automatically mean clean.

The reassuring data, read honestly

There is a fairer other side, and we will not bury it. Good samples and reputable products can test clean. In one carefully analysed native Himalayan sample, several regulated heavy metals were below detectable limits, though that was a single sample and it did not explicitly test mercury or cadmium.

In one carefully analysed native Himalayan sample, regulated heavy metals including lead, arsenic, chromium, cobalt and nickel were below detectable limits, though it was a single sample that did not explicitly test mercury or cadmium. [Basavaraja 2025, ACS Omega] Preliminary evidence

Independent 2024 testing of eight popular shilajit supplements found lead, cadmium, arsenic and mercury below single-daily-dose levels of concern, but fulvic-acid content varied by about 32,000 percent between products. [ConsumerLab 2024] Moderate evidence

Two caveats keep that reassurance in proportion. First, the metal results applied at one dose per day for those specific reputable brands, and do not generalise to unbranded raw resin or to taking several servings. Second, the same testing exposed wild label inaccuracy, with fulvic-acid content varying enormously between products. A number printed on a jar is not verification.

The “detox” myth, backwards

A persistent marketing claim is that shilajit detoxes heavy metals from your body. There is no credible evidence for that, and the documented reality points the opposite way. Raw shilajit can add heavy metals, including thallium, to your intake rather than removing them. Treat any detox claim on a shilajit product as a reason for more scepticism, not less.

What to demand before you buy

Because regulators do not pre-approve or routinely test these supplements for purity, the responsibility falls on the buyer. A recent third-party Certificate of Analysis is the single most protective check you can make.

Shilajit is sold as a dietary supplement that is not pre-market tested by regulators for quality or purity, so a recent independent Certificate of Analysis is the single most protective buyer check. [OPSS (US DoD)] Strong evidence

• Insist on a recent third-party Certificate of Analysis that tests arsenic, lead, mercury, and cadmium, and ideally thallium, against a stated limit.
• Never buy raw, loose, or unprocessed resin sold with no purification claim.
• Treat a purified label as a starting point, not proof, given that some supplements exceeded raw resin on thallium.
• Ignore folk tests such as whether resin dissolves or softens with heat; they say nothing about metal safety.

Contamination is the one shilajit topic where the evidence is genuinely strong and the stakes are real. If you go further, our buying guide walks through reading a Certificate of Analysis, the side effects and safety guide covers who should avoid shilajit entirely, and the FAQ answers the common questions about fakes and testing.

References

1. Stohs SJ. Safety and efficacy of shilajit. Phytother Res. 2014;28(4):475-9. PMID 23733436
2. Saper RB, et al. Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the internet. JAMA. 2008;300(8):915-23. PMID 18728265
3. Kamgar E, et al. Quantifying thallium in shilajit and its supplements. BMC Chemistry. 2025. PMID 39827344
4. Basavaraja D, et al. Chemical analysis of native Himalayan shilajit. ACS Omega. 2025;10(47):57097-106. PMID 41404054
5. ConsumerLab.com. Shilajit supplements review, heavy metals and fulvic acid. 2024. ConsumerLab 2024
6. US FDA. FDA warns about heavy metal poisoning associated with certain unapproved Ayurvedic drug products. FDA
7. US DoD Operation Supplement Safety. Shilajit as a dietary supplement ingredient. OPSS