Evidence Tiers, Explained: What Our Badges Actually Mean

Educational content only — this is not medical advice.

We put a badge on every peptide because the single most important — and most hidden — fact about any health claim is what kind of evidence stands behind it. This is a meta piece: no new studies, just the rulebook we grade by. Here are the four tiers, from strongest to weakest.

Human RCT

The gold standard. Randomized, placebo-controlled trials in humans — the design built specifically to separate a real effect from wishful thinking, placebo, and bias. Randomization balances the groups; the placebo control tells you what would have happened anyway; blinding stops expectations from coloring the result.

When we award this badge, there is at least one published human RCT behind the core claims. On this site, retatrutide gets it because its weight-loss and metabolic effects come from published randomized trials, not testimonials.

Human

Human evidence, but not a rigorous randomized trial for the claim in question — think small controlled studies, cosmetic trials, open-label work, or early-phase studies. Real signal, real people, weaker design. GHK-Cu lands here: its skin-firmness and wrinkle data come from small controlled human cosmetic trials, which is genuine human evidence, but it is narrow and cosmetic, not proof of the broader "regenerative" story.

Preclinical

The compound has been studied in cells or animals, but human proof is missing. This is where most "research peptides" actually live — BPC-157 and TB-500 among them. Preclinical results can be exciting and can absolutely justify running human trials. What they cannot do is tell you what will happen in your body. "Promising in mice" is a starting line, not a finish line.

Anecdotal

The weakest tier: testimonials, forum reports, before/after photos, and personal experience. No control group, no blinding, no way to rule out placebo or coincidence. Useful for generating hypotheses; useless as proof. If a claim rests only on this, treat it as a rumor with good lighting.

Why we bother

Most peptide marketing works by blurring these lines — quoting a dramatic rat study as if it were a clinical result, or stacking testimonials until they feel like data. The badge exists to un-blur it in one glance. A tier is a promise about study type, and we would rather show you an honest "preclinical" than a flattering lie. For how this plays out across real compounds, see Peptides 101.