chemical probe

A chemical probe is a molecule used not as a medicine but as a research tool, a way to poke a single protein in a cell and watch what happens. Think of it as a precise scalpel for biology: switch off one target cleanly and see which functions break.

Formally, it is a selective small molecule used to study a target's biological function experimentally. A good probe must be potent, hit its intended target strongly while leaving others alone, and work at concentrations where its effects can be trusted to come from that one target.

Probes are vital for testing whether a target is worth pursuing as a drug, which is part of target validation. They are held to strict quality standards, because a poorly characterized probe with hidden off-target effects can mislead an entire field into chasing the wrong biology.