lowest observed adverse effect level
The lowest level of a substance that has been observed to cause harm in an exposed population
The Lowest Observed Adverse Effect Level (LOAEL) is the smallest amount of a substance—like a chemical, contaminant, or additive—that has been shown to cause harmful effects in experiments, usually in animals or humans. It represents the lowest dose at which negative health effects are observed.
EFSA uses the LOAEL when assessing the safety of substances in food. By knowing the LOAEL, EFSA can determine safe exposure levels for humans, often applying safety factors to account for differences between animals and humans or variability among people. This helps set limits such as Tolerable Daily Intakes (TDIs) or Maximum Residue Levels (MRLs), ensuring that consumption of food does not cause harm even at low exposure levels.