|ShilNepal Editorial
shilajit harvesting process - pure Himalayan resin on mountain rock

How Himalayan Shilajit Is Harvested and Purified

Shilajit does not arrive ready to use. Between a rock face and a tin on a shelf are two steps: collection and purification. This page describes both as they are documented, and is explicit about a gap that most sellers skip over: we found no published study that measured whether purification actually reduces heavy metals in shilajit. That is why independent batch testing, not the description of the process, is what establishes safety.

In this article

  1. Collection
  2. What raw resin contains
  3. Purification
  4. The evidence gap
  5. Why testing is the real check

Key takeaways

  • Shilajit exudes from steep rock faces. A geological study of Tibetan sites found exudation points mainly on sunny cliffs with slopes of 60 degrees or more at 2,000 to 4,000 m; other sources quote higher elevations.
  • Raw material is not clean. It can carry soil, plant debris and the metals present in the rock. A 2024 review reported around 65 metals in shilajit, mostly below limits but with some exceedances.
  • The traditional purification, soaking, cloth filtering and slow evaporation, is documented in general terms. No published study we found compared metal levels before and after it, so a batch laboratory report is the only evidence of a result.

Collection

Shilajit is collected by hand from rock where it seeps out. In the geological study of Tibetan material, exudation points were mainly on steep, sunny cliffs, on slopes of 60 degrees or more, at altitudes of 2,000 to 4,000 m, where cavities protected from rain erosion store organic matter that flows out along pores and fissures (Ding 2020). That study notes the points are hard to reach, and a 2024 paper on Tibetan shilajit says material harvested above 2,000 m is difficult to obtain and varies in quality with its complex geography (Ding 2024). Collection is therefore seasonal, manual and limited, which constrains supply. For the formation and origin debate see Shilajit and Altitude.

What raw resin contains

Material taken from rock is a mixture. Besides humic and fulvic substances it can include soil, small stones, plant fragments and mineral impurities. A 2024 review reported that shilajit contains around 65 metals, including copper, aluminium, lead, arsenic, cadmium and mercury, usually below WHO and FDA limits but with some studies reporting exceedances, and concluded that using it without knowing the metal levels is not safe (Hussain 2024). A 2025 study quantified thallium in natural shilajit at up to 0.226 micrograms per gram (Kamgar 2025). Raw material from informal sellers is therefore a genuine risk; see what to check before buying on eBay.

Purification

In Ayurvedic pharmacognosy the purification step is called Shodhana. In its commonly described form, crushed raw material is soaked in water so the soluble fraction separates from heavy sediment, the liquid is filtered through cloth to remove grit and plant debris, and it is evaporated slowly, traditionally in the sun, to a resin. Details vary by practitioner. See Shodhana: the traditional purification method. Our own resin is hand-collected in Nepal, water-purified and sun-dried, then tested by batch before it is packed for Australian customers.

The process is traditional and plausible. Whether it removes metals has not, as far as we found, been measured in a published study.

The evidence gap

We searched about 145 PubMed records on shilajit and related names. They include chemical characterisations of different samples (for example Kohli 2026 and Basavaraja 2025), quality-control methods (Ding 2024) and metal surveys, but none compares the same material before and after traditional purification. Two consequences follow:

  • Claims that traditional purification "removes heavy metals" are not supported by a study we could find. The mechanistic argument, that soluble humic substances separate from insoluble sediment, is plausible, but dissolved metals could pass through a cloth filter.
  • Claims that slow, low-heat processing preserves composition better than industrial extraction are also untested in comparative work.

Why testing is the real check

Because the effect of purification is unmeasured in the literature, the only way to know what a finished batch contains is to test it. Look for a named laboratory, the metals tested, results with units and the limits used, and the batch number on the product. See how to read a lab test report.

Lab results, batch #1093

Collected, purified, then tested

Batch #1093 had heavy metals independently tested by Eurofins Food Australia, and the results are public.

Read the batch #1093 report

A lab report describes one batch. It does not show that a product treats or prevents any condition.

FAQ

What is the traditional purification method called?

Shodhana: soaking, filtering and slow evaporation, traditionally in the sun.

Is raw shilajit safe to use?

Not reliably. It can carry soil, plant matter and metals from the rock.

Does purification remove heavy metals?

We found no published study measuring this. Batch testing is the check.

When is shilajit harvested?

In warmer months, when it is accessible and soft enough to collect by hand.

References

  1. Ding R, Zhao M, Fan J, et al. Mechanisms of generation and exudation of Tibetan medicine shilajit (Zhaxun). Chin Med. 2020;15:65. DOI: 10.1186/s13020-020-00343-9. PMID: 32612671.
  2. Ding R, He S, Wu X, et al. Efficient generation of HPLC and FTIR data for quality assessment using time series generation model: a case study on Tibetan medicine shilajit. Front Pharmacol. 2024;15:1503508. DOI: 10.3389/fphar.2024.1503508. PMID: 39624838.
  3. Hussain A, Saeed A. Hazardous or advantageous: uncovering the roles of heavy metals and humic substances in shilajit. Biol Trace Elem Res. 2024;202(12):5794-5814. DOI: 10.1007/s12011-024-04109-4. PMID: 38393486.
  4. Kamgar E, Zembrzuska J, Zembrzuski W, Kaykhaii M. Quantifying of thallium in shilajit and its supplements. BMC Chem. 2025;19(1):20. DOI: 10.1186/s13065-025-01384-7. PMID: 39827344.
  5. Kohli HK, Somasekhar V, Reddy MD, Prakash NS. Shilajit analytical study of the phyto complex in raw material, extract and resin by hyphenated techniques. J Chromatogr A. 2026;1766:466570. DOI: 10.1016/j.chroma.2025.466570. PMID: 41330163.
  6. Basavaraja D, Katkar R, Dhaka P, et al. Chemical analysis of native Himalayan shilajit: an evaluation of an Ayurvedic formulation. ACS Omega. 2025;10(47):57097-57106. PMID: 41404054.

Findings above are drawn from published abstracts; full texts were not reviewed. The description of our own process comes from our product and purification pages.

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