threshold dose

The threshold dose is the smallest amount of a substance or exposure needed to produce a measurable or noticeable biological effect in the body. Below this level, the substance typically does not cause any observable harm or response. It is a concept used in toxicology and medicine to help determine safe exposure limits, recognizing that some substances only become harmful once they reach a certain dose. Essentially, the threshold dose marks the point where effects start to occur, allowing for better risk assessment and management of exposures.