- Six levels: Strong, Moderate, Limited, Very limited, Preclinical only, Not studied.
- Ratings are set by study design, size, comparison and replication, an approach informed by the GRADE system used in medicine.[1]
- No shilajit topic currently rates above “Limited”.
- A rating is about evidence for a topic, not about safety or about a particular brand.
The six levels
What decides a rating
| Factor | Moves the rating up | Holds the rating down |
|---|---|---|
| Who was studied | People | Cells or animals only |
| Comparison | Randomised against placebo, blinded | Before-and-after with no control group |
| Outcome | Something people would notice or that predicts health | A biomarker or gene-expression change |
| Size and duration | Larger samples, longer follow-up | Dozens of people for a few weeks |
| Replication | Repeated by an independent group | A single study, or one group only |
| Directness | Tested on the population and product type in question | Different population, or a different preparation |
Funding is always reported alongside a rating. It does not, by itself, change the rating, but where most studies of a topic test one supplier’s product, independent replication carries more weight. See who funds shilajit research.
Two worked examples
Testosterone: rated Limited
One randomised, placebo-controlled trial in 75 healthy men aged 45–55 reported higher testosterone after 90 days on a purified extract.[2] It is a controlled human trial on a relevant outcome, which earns “Limited”. It doesn’t reach “Moderate” because it is a single, unreplicated study in one age group using one preparation.
Male fertility: rated Very limited
The main study enrolled 35 men with low sperm counts and compared semen measures before and after 90 days, with no placebo group.[3] Without a comparison group, the changes can’t be attributed to shilajit with confidence, so the rating stays at “Very limited”.
Evidence about shilajit vs evidence about a product
The six levels above rate research on shilajit in general. A specific product is judged on a different set of evidence, and the two are never merged: a positive trial on one extract says nothing about what is in a particular jar, and a clean lab report says nothing about health effects.
| Evidence | About | Can establish | Can’t establish |
|---|---|---|---|
| 1. Published scientific literature | Shilajit generally | What has been tested, and the rating on this page | Anything about a specific product |
| 2. Laboratory reports | A tested sample | What was found in that sample | Other batches; health effects |
| 3. Brand documentation | The product | What the brand states | Whether it is true |
| 4. First-hand purchase test | One order | That ordering and delivery worked | Authenticity, purity, efficacy |
| 5. Consumer feedback | Respondents’ experience | How people rated taste, ease of use and value | Health effects; representativeness unless the method shows it |
| 6. Editorial conclusion | All of the above | Our assessment, with reasons | More than the evidence beneath it |
For a worked example of how the product-side evidence is kept separate, see the Nature Elixirs evaluation. The same structure applies to every brand.
What a rating does not mean
- Not a safety ratingA topic can be “Not studied” and the product still safe, or “Limited” and unsuitable for you. Safety is covered on Is shilajit safe?
- Not a product scoreRatings describe research on a topic. Brands are assessed separately on UK shilajit brands.
- Not a promise of effectEven “Limited” evidence only applies to the people and preparation studied.
How ratings are updated
New papers are logged on the new studies log and checked against the criteria above. A rating changes only when the new study changes the picture: for example, an independent randomised trial on a topic that previously had one. Changes are recorded on the updates log. The full internal method, including how individual studies are appraised, is on how we grade evidence, and a short reader’s guide is on how to use a shilajit evidence rating.
Common questions
Why does no topic rate higher than Limited?
Because no topic has more than one or two small controlled human trials, and none has been independently replicated. See all topics.
Is this the same as GRADE?
No. It borrows GRADE’s core ideas, such as judging certainty across a body of evidence, but it is simplified for consumers and applied to supplement topics.[1]
Can a brand ask for a rating to change?
Anyone can send us a study. Topic ratings cover shilajit research in general, not any brand, and change only if a study meets the criteria. How commercial relationships are handled is set out on conflicts of interest.
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.
- Guyatt GH, Oxman AD, Vist GE, et al.. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ 336(7650):924–926, 2008. doi:10.1136/bmj.39489.470347.AD; PMID 18436948. View source (opens in a new tab) [Methods paper]
- Pandit S, Biswas S, Jana U, De RK, Mukhopadhyay SC, Biswas TK. Clinical evaluation of purified Shilajit on testosterone levels in healthy volunteers. Andrologia 48(5):570–575, 2016. PMID 26395129. View source (opens in a new tab) [Randomised controlled trial]
- Biswas TK, Pandit S, Mondal S, et al.. Clinical evaluation of spermatogenic activity of processed Shilajit in oligospermia. Andrologia 42(1):48–56, 2010. PMID 20078516. View source (opens in a new tab) [Uncontrolled clinical study]