Shilajit has moved from Ayurvedic clinics to online marketplaces and gym shelves in a few years, usually sold as a testosterone and energy booster. The research behind those claims is much thinner than the marketing. The risks are also less discussed. Because shilajit forms in rock, metals can end up in it, and published analyses suggest the safety question depends heavily on the specific product.
Shilajit is a tar-like, mineral-rich substance that seeps from rock in high mountain ranges. It is used in Ayurveda, India's traditional medicine system, as a rasayana, a rejuvenating tonic. Its main reported components are fulvic acid, humic acid, dibenzo-alpha-pyrones and trace minerals. Human evidence for health benefits is limited to a few small trials.
Shilajit is collected from Himalayan rock faces and from other mountain regions in Central Asia. Published reviews describe it as a product of long decay of plant material, with microbes involved. A review in Current Nutrition & Food Science describes it as a multi-component herbomineral substance and attributes its reported effects mainly to humic acid, fulvic acid, dibenzo-α-pyrones, related chromoproteins and trace elements.
Because it is a natural exudate, no two batches are identical. A review summarised by News-Medical notes that variations in sourcing and composition make standardization difficult, complicating reproducibility and regulatory approval.
The fulvic acid figure is where labels get confusing. Many websites say purified shilajit is 60% to 80% fulvic acid. ConsumerLab, an independent testing company that sells subscriptions to its reviews, reports that purified resins are about 6% to 7% fulvic acid, while extracts are roughly 60% to 80%. The two numbers describe different products, and a label that gives a percentage without saying what it was measured in is hard to interpret. Examine.com's research summary describes a trial using 2 grams a day of shilajit with 6.61% fulvic acid, which fits the lower figure.
In Ayurveda, shilajit is described as a rejuvenator and anti-ageing substance. One of the reviews cited above notes that use as an adaptogen, aphrodisiac, rejuvenator and anti-aging substance is mentioned in many ancient texts. Ayurvedic practice also stresses purification (shodhana) before consumption, and some Indian sellers say raw shilajit should never be eaten. Those sellers have a commercial interest, but the point matches the contamination data discussed below.
Traditional use is not clinical evidence. A text recommending a substance for centuries tells us how it was used, not whether it works or how safe it is by modern standards.
Most claims online trace back to a small set of human trials, plus a much larger body of laboratory and animal work. Lab and animal findings, such as effects on inflammation or cell signalling, do not show that shilajit improves any health outcome in people.
Testosterone. The most cited human trial, in the journal Andrologia (Pandit et al., 2016), was randomised, double-blind and placebo-controlled. It enrolled 75 healthy volunteers aged 45 to 55 at J.B. Roy State Ayurvedic Medical College and Hospital in Kolkata, who took 250 mg of a branded shilajit twice daily for 90 days. Trade press reported that the shilajit group showed a 20% rise in total testosterone and a 19% rise in free testosterone compared with placebo.
Three caveats apply. The sample was small and the follow-up short. The product was Natreon's patented PrimaVie, so results may not carry over to other products. And the study measured hormone levels, not symptoms, fertility or any outcome a man would feel. Whether a modest rise in a lab value in men aged 45 to 55 matters clinically is not something this trial answers.
Muscle strength. A 2019 randomised trial in the Journal of the International Society of Sports Nutrition tested the same branded product in 63 men, with 21 per group. The authors from the University of Nebraska-Lincoln found that 500 mg a day for 8 weeks helped retain maximal muscular strength after a fatiguing protocol and lowered baseline hydroxyproline, a marker linked to collagen breakdown. Again, small, short and tied to one branded ingredient. The authors themselves call for larger studies using different exercises.
Everything else. Claims about cognition, blood sugar, cholesterol, bone health, anaemia and heart health rest on small studies, animal work or lab experiments. Examine.com notes, for example, that a cholesterol-lowering result came from one trial in which blood glucose did not fall with 2 grams of shilajit over 45 days, while a different, lower-dose product trial reported a drop. Mixed results from different products and doses are a reason for caution, not a basis for confident claims.
I did not conduct interviews for this piece, and none of the views below are from direct conversations. They come from published reviews and testing reports.
ConsumerLab's review concluded that purified resin and extracts appear well tolerated in most adults, but studies have been small and preliminary, and larger controlled studies are needed, particularly for long-term use. Its testing also found that fulvic acid per serving ranged from 6.9 mg to 2,206 mg across products, and that it is hard to judge strength from labels. That is a wide spread for a supplement sold on a single compound.
Companies that supply branded shilajit extracts point to clinical trials as evidence. Natreon, which makes PrimaVie, has described the Nebraska study as the ninth clinical trial on its ingredient, and its executives say sports nutrition is a primary focus. That is a legitimate commercial position, but readers should know that the two best-known human trials tested its product, and that a manufacturer promoting results is not an independent verification of them. I could not confirm from the sources I reviewed who funded each trial, so that is flagged for checking below.
Many retail brands, particularly on marketplaces, say their shilajit is "100% pure" or "lab tested." Neither phrase is a standard. Unless a label links to a batch-level certificate of analysis, these are marketing statements.
The most concrete consumer concern is not an exotic side effect. It is what else is in the jar.
Shilajit forms in rock, so it can carry metals. A 2025 paper in BMC Chemistry measured thallium, a highly toxic metal, in natural shilajit and commercial supplements. It found up to 0.226 micrograms per gram in natural shilajit, and the authors said some supplements had more thallium than crude shilajit. They called for regular monitoring and standardised testing. The study analysed a limited set of samples, so it does not show that every product is unsafe, but it does show the risk is not hypothetical.
Results elsewhere are mixed, which is itself informative. A 2016 analysis of two raw samples from Pakistan found metals within WHO permissible levels. Contamination appears to vary by source and processing, which is why a certificate for your specific batch matters more than a brand's general reputation. Standard panels cover lead, arsenic, mercury and cadmium. Some commentators note that thallium is often left out, but I could not verify how common that omission is.
Other points to keep in mind:
Safety data for long-term use are limited, as noted above.
Anyone with a hormone-related condition, a metal-storage condition such as haemochromatosis, gout or kidney disease, who is pregnant, or who takes prescription medicines should speak to a doctor first. Some consumer sites list iron content and uric acid as concerns, but I did not find a primary source for this, so treat it as a question to ask a clinician rather than an established risk.
Shilajit should not replace prescribed treatment or a proper work-up for low energy or low testosterone, which can have many causes.
In India, shilajit can be sold as an Ayurvedic product or as a food supplement, and the regulatory route affects what testing and licensing apply. Some online guides say enforcement is inconsistent, though I could not confirm that against a regulator's own statement. Rather than rely on a logo, check these points:
Licence on the label. Look for a valid FSSAI number, or an AYUSH manufacturing licence for Ayurvedic products. Verify the FSSAI number on the regulator's site.
Batch-specific lab report. It should be from an accredited lab, match the batch number on your pack, and list actual results, not just "passed."
Metals tested by name. Lead, arsenic, mercury and cadmium at minimum. Ask whether thallium is included.
Fulvic acid stated with a method. And clarity on whether the figure refers to resin or extract.
Dose that matches the research. The trials above used 250 to 500 mg a day of a specific extract, not larger amounts of an unknown product.
Purification disclosed. Raw, unpurified shilajit should be avoided.
Claims that stay within the evidence. Be wary of "clinically proven," "cures" or hormone-boosting promises, and of citations to a trial of a different product.
Price. Very cheap "Himalayan" resin is a warning sign. A high price does not prove quality either.
Three developments would change the picture: independent trials that are not tied to a single branded extract, larger and longer safety studies, and regulators or standards bodies setting clear limits and test panels for shilajit, including thallium.
Shilajit has a long history in Ayurveda and a small amount of human research suggesting possible effects on testosterone and exercise-related strength with one branded extract. It has not been shown to treat any disease, and its long-term safety is not established. The more practical problem for buyers is that products vary widely in composition and may contain metals. Anyone considering it should check batch-level testing and talk to a doctor first.
Pandit S, et al. Clinical evaluation of purified shilajit on testosterone levels in healthy volunteers. Andrologia, 2016. Trade coverage: https://www.nutraingredients.com/Article/2015/10/06/Shilajit-supplements-may-boost-testosterone-for-healthy-men-RCT/ (secondary; original paper should be cited directly)
Keller JL, et al. Effects of shilajit supplementation on fatigue-induced decreases in muscular strength and serum hydroxyproline levels. J Int Soc Sports Nutr 2019;16:3. https://pmc.ncbi.nlm.nih.gov/articles/PMC6364418 (peer-reviewed)
Quantifying thallium in shilajit and its supplements. BMC Chemistry, 2025. https://link.springer.com/article/10.1186/s13065-025-01384-7 (peer-reviewed)
Rahim M, et al. Heavy metal profile of shilajit samples from Gilgit and Chellas, Pakistan. J Phys Sci 2016. https://jps.usm.my/heavy-metal-profile-shilajit-samples (peer-reviewed)
Shilajit review, Current Nutrition & Food Science 15(2). https://benthamdirect.com/content/journals/cnf/10.2174/1573401313666170823160217 (peer-reviewed review)
ConsumerLab shilajit review, 2024: https://consumerlab.com/reviews/shilajit/shilajit-supplements (independent tester, subscription business)
Examine.com shilajit research summary: https://examine.com/supplements/shilajit/research/ (secondary)
News-Medical, Shilajit: Health Benefits, Risks, and Clinical Evidence: https://www.news-medical.net/health/Shilajit-health-benefits-risks-and-clinical-evidence.aspx (secondary)
Natreon / trade coverage of the 2019 study: https://www.nutraceuticalsworld.com/breaking-news/shilajit-ingredient-linked-to-retention-of-muscular-strength-and-decreased-hydroxyproline/ (company-sourced)