Study design
In vitro
Research performed outside a living organism, often in cells or test tubes.
What it means
Definition
In vitro: In vitro evidence can be useful for early biology, but it is usually far from proving real-world clinical benefit.
What it can tell you
It can show how close the evidence is to a real human health outcome.
What it cannot tell you
It cannot prove that a treatment works in people unless human outcome data are available.
Headline trap
Why this matters in headlines
An in vitro antiviral effect does not prove that taking the substance helps infected people.