Preclinical evidence
In plain language
Findings from lab and animal studies done before a treatment is ever tested in humans.
Technical definition
Data generated from in-vitro (cell) and in-vivo (animal) studies conducted prior to human trials; hypothesis-generating but often failing to translate to human outcomes.
Preclinical results are an important early signal but frequently do not hold up in people — effects seen in cells or rodents often differ in humans because of dose, metabolism, and biology. Claims resting only on preclinical evidence carry high uncertainty.