How we rate evidence
Every factual claim on this site carries a named source. When we cannot find one, we say so rather than borrowing a figure from another supplement site.
The three grades
Strong. Supported by randomized controlled trials in humans, or by a consistent body of human research. The finding would survive a reader checking our citations.
Limited. Some human evidence exists, but it is small, indirect, conducted in a specific patient group, or inconsistent. Reasonable people could read it differently.
None. No controlled human trials support the claim. This includes claims that are plausible, traditional, or widely repeated. Plausible is not the same as demonstrated.
Which sources we use
We rely on primary research indexed in PubMed, US regulatory documents such as FDA labels and safety communications, MedlinePlus, NIH resources including the Office of Dietary Supplements and the Dietary Supplement Label Database, and peer-reviewed journals. Academic institutions such as the Linus Pauling Institute are used where they restate primary data with citations.
We do not cite supplement brands, retailers, affiliate sites, or content aggregators, even when their pages rank well.
When a number cannot be traced
Some figures circulate widely without an origin. Where we find this, we report it as a finding rather than quietly omitting it. An unsourced number that millions of readers have seen is itself worth documenting.
Corrections
Research changes and we make mistakes. Pages carry a last-updated date, and material corrections are noted in the page rather than edited away silently.
What this site is not
SupplementHub does not diagnose, treat, or recommend products for individuals. We describe what has been studied and how reliably. Decisions about your own health belong with a qualified professional who knows your history and medications.