How animal toxicology studies work
Toxicology studies give animals a substance at several doses, often far higher than people would take, and watch for harm. Short studies look at a single dose or a few weeks; repeated-dose studies run for around 90 days, examining body weight, blood tests, organ weights and tissue under the microscope at the end. The aim is to find doses that cause harm and doses that don’t, as a first step before human use.
The 91-day rat study
A study published in 2012 gave black shilajit to rats at different dose levels for 91 days and examined them for signs of toxicity. The authors reported that it was safe for long-term use at the doses tested, and suggested it could be used as a supplement in conditions such as iron deficiency anaemia.[1] The safety finding is useful; the suggestion about anaemia was the authors’ interpretation, not something the study tested; see iron and anaemia.
What safety reviews conclude
A 2014 safety review of shilajit concluded that animal studies had not shown significant toxicity and that human studies reported no serious adverse effects.[2] A 2011 review of shilajit pharmacology raised separate concerns about the design of some early studies, including doses and controls,[4] which is a reminder to read individual studies critically.
What animal studies can’t tell you
| Limitation | Why it matters |
|---|---|
| Species differences | Rats and people process substances differently |
| Specific preparation | Results describe the material tested, not every product |
| Contamination | A clean test sample says nothing about a contaminated product |
| Duration | 90 days in rats doesn’t cover decades in people |
| Rare reactions | Allergies and rare effects rarely show in animals |
Why contamination is a separate question
Toxicology studies test a particular sample. If that sample was clean, the study tells you about shilajit itself, not about a product made from different raw material. Research has found thallium in some shilajit supplements at higher levels than in crude samples,[3] and metals in some Ayurvedic products bought online.[5] Product safety therefore depends on batch testing as much as on toxicology; see why contaminant testing matters.
Where toxicology sits in the evidence
For safety, the evidence builds in layers: animal toxicology, then short human trials, then longer trials and real-world reporting. Shilajit has the first two layers, with human trials of up to 48 weeks reporting it as well tolerated.[6] The third layer is still thin; see what a safety study can tell you and human vs animal evidence.
Reading a toxicology claim
- “Proven non-toxic”Animal studies can’t prove that for people.
- “Safe at any dose”No study supports this.
- “Tested for safety”Ask: which preparation, which species, how long?
Doses and safety margins
Animal studies often use doses far higher, relative to body weight, than people take. When no harm appears at high doses, it suggests a margin of safety at normal doses. That logic is useful but imperfect, because species differ and because contaminants in a different product weren’t present in the test material. It is one reason toxicology is the beginning, not the end, of safety assessment.
What would add to the picture
More detailed toxicology on well-characterised commercial products, longer human trials with blood monitoring of kidney and liver function, and better real-world reporting would all strengthen the safety picture. Until then, combining the reassuring animal data with batch testing and sensible use is the practical approach.
Putting it into practice
When a product page says shilajit is “tested for safety”, ask what that means. Is it citing animal toxicology for a different preparation, or a batch report for the product on sale? Both have value, but only the batch report tells you about the jar you buy.
A note on study quality
Not all animal studies are equal. Better studies use several dose levels, include control groups, examine organs in detail and report their methods clearly. When a product cites an animal study as proof of safety, it is worth checking which study, which preparation and how it was designed.
The bottom line
Animal studies of shilajit have generally found no significant toxicity at the doses tested, which is reassuring. They can’t predict contamination in a specific product or rare reactions in people. Combine that reassurance with a batch-tested product and sensible use.
Frequently asked questions
Is shilajit toxic?
What did the 91-day rat study find?
No significant toxicity at the doses tested over 91 days.[1]
Do animal studies prove shilajit is safe for people?
No. They are an early step and can’t capture species differences, rare reactions or contamination.
Why do toxicology studies use high doses?
To find levels that cause harm and establish a margin of safety.
Does a clean toxicology study mean my product is clean?
No. It describes the sample tested. Check your product’s batch report.
Were there concerns about early studies?
A 2011 review raised concerns about doses and controls in some early pharmacological studies.[4]
How long have human trials lasted?
Up to 48 weeks.[6]
What is the next step for safety research?
Longer human studies and better real-world reporting.
Sources & further reading
Primary research, regulators and standards bodies are cited first. A source being listed here does not mean it supports every claim made by sellers; it supports the specific statement it is attached to.
- Asian Pacific Journal of Tropical Biomedicine authors. Evaluation of safety profile of black shilajit after 91 days repeated administration in rats. Asian Pacific Journal of Tropical Biomedicine, 2012. View source (opens in a new tab) [Animal safety study]
- Stohs SJ. Safety and efficacy of shilajit (mumie, moomiyo). Phytotherapy Research 28(4):475–479, 2014. PMID 23733436. View source (opens in a new tab) [Review]
- Quantifying of thallium in Shilajit and its supplements to unveil the potential risk of consumption of this popular traditional medicine. BMC Chemistry 19:20, 2025. doi:10.1186/s13065-025-01384-7. View source (opens in a new tab) [Laboratory analysis]
- Wilson E, Rajamanickam GV, Dubey GP, et al.. Review on shilajit used in traditional Indian medicine. Journal of Ethnopharmacology 136(1):1–9, 2011. doi:10.1016/j.jep.2011.04.033; PMID 21530631. View source (opens in a new tab) [Review]
- Saper RB, Phillips RS, Sehgal A, et al.. Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the Internet. JAMA 300(8):915–923, 2008. View source (opens in a new tab) [Cross-sectional product survey]
- Pingali U, Nutalapati C. Shilajit extract reduces oxidative stress, inflammation, and bone loss to dose-dependently preserve bone mineral density in postmenopausal women with osteopenia: a randomized, double-blind, placebo-controlled trial. Phytomedicine 105:154334, 2022. doi:10.1016/j.phymed.2022.154334; PMID 35933897. View source (opens in a new tab) [Randomised controlled trial]