What does evidence tier actually mean on compound pages?

RORena Okoro· 3 months ago

Research & educational use only. This content is not medical advice. Consult a qualified healthcare professional before using any peptide compound.

I keep seeing compounds labeled Tier 1 through Tier 4 on their pages. Can someone explain in plain language what those tiers actually mean and why a compound with lots of animal studies can still be a low tier?

I think I understand that human randomized trials are the top, but I do not fully get why observational studies rank below them.

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2 Replies

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DCDr. Sarah Chen researcher· Expert· 2 months ago

The tiers rank how confidently we can attribute an effect to the compound. Tier 1 is human randomized controlled trials, where randomization balances known and unknown confounders so a difference in outcome can be credited to the intervention. Tier 2 is human observational data, which is suggestive but vulnerable to confounding. Tier 3 is animal-only, and Tier 4 is theoretical or mechanistic.

That is why a compound with dozens of animal studies and no human trials stays at Tier 3: volume of animal work does not substitute for a controlled human result.

Accepted solution
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BLBea Lindqvist· Expert· 2 months ago

The confounding intuition is the part that made it stick for me. Observational groups differ in ways you cannot fully measure.

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