Evidence levels

Every article on HPR carries one of five labels. They run from strongest to weakest. The stronger the evidence, the heavier the badge.

Label	What it means
Meta-analysis	A systematic review or meta-analysis that pools several human studies. The strongest evidence we cover.
Human RCT	A randomised controlled trial in people: participants were randomly assigned to the peptide or a comparison, ideally blinded.
Human study	A human study without randomisation: open-label trials, cohorts, case series, pilot studies. Useful, but easier to fool.
Preclinical	Cell or animal research. It tells you what might be worth testing in people, not what happens in people.
Self-reported	A first-hand report from a reader. Context, never proof.

Why this matters for peptides

For most peptides discussed online, almost all the evidence is preclinical. A peptide can heal tendons in rats and do nothing in people, or do something different. When an article is labelled preclinical, read it as “promising, untested”.

How we choose the label

The label reflects the strongest evidence the article itself rests on. A guide that covers one small human pilot and twenty rat studies is labelled Human study, and the text says plainly how thin that human evidence is.