Methodology
BioSignal reaches a conclusion the way a careful scientist would: by weighing every relevant stream of evidence, favoring the strongest, and being explicit about what remains uncertain.
The evidence hierarchy
Not all evidence carries equal weight. BioSignal ranks evidence by how directly and reliably it answers the question “does this work in humans?” — from pooled human data at the top to preclinical studies at the base. Higher tiers can overturn lower ones; lower tiers cannot override strong human evidence.
Systematic reviews & meta-analyses
The strongest single sources: they pool many human trials under a defined protocol, weighting for quality and revealing whether an effect holds across studies. When a rigorous review exists, it anchors the record.
Human clinical trials
Randomized controlled trials test an intervention against a control in people. Well-designed, adequately powered, independently replicated trials are the backbone of a confident human conclusion.
Expert consensus & guidelines
Position statements from scientific bodies synthesize evidence into practice. Valuable context, but weighed against the primary studies behind them rather than accepted on authority.
Mechanistic evidence
Biochemical and physiological reasoning explains how something could work. It establishes plausibility and generates hypotheses — but a plausible mechanism is not proof of a human effect.
Animal & in-vitro studies
Preclinical studies are essential for discovery but translate unreliably to people. On their own they cannot establish that an intervention works in humans; they inform, they do not conclude.
Synthesizing multiple evidence streams
Real questions rarely rest on a single study. A record synthesizes the streams together: strong human data sets the direction, mechanistic and preclinical work explains it, and expert consensus provides context. When the streams agree, confidence rises. When high-quality human trials contradict a compelling mechanism, the human data wins — a plausible story is not a demonstrated effect.
Consistency across independent studies matters as much as any single result. A finding that replicates in different populations and research groups is far more trustworthy than a lone striking outcome, however large.
How uncertainty is handled
Uncertainty is reported, not hidden. Where evidence is thin, indirect, or conflicting, the record lowers its confidence and states the open questions explicitly. BioSignal would rather say “we don’t yet know” than manufacture a false verdict — an honest unknown is more useful, and more trustworthy, than confident guesswork.
Why confidence is not effectiveness
This distinction is central to reading BioSignal correctly. Confidence describes how strong and consistent the evidence is. Effectiveness (or effect size) describes how large the benefit is when it exists. They are independent.
A supplement can have High confidence in a small effect — we are sure it does a little. Another can show a large effect in a single study but earn only Limited confidence — the result is exciting but unproven. A high confidence score is a statement about the quality of the evidence, never a promise of a big result. The Confidence Levels page explains each level in detail.
Spotted something unclear or out of date? We read every note.
Give feedback