The NOEL (no observable effect level) is the highest dose or exposure level of a substance or material that produces no noticeable (observable) toxic effect on tested animals. The LOAEL is the lowest dosage level at which chronic exposure to the substance shows adverse effects on tested animals.

What does no observed effect level?

No-observed-effect level (NOEL): greatest concentration or amount of a substance, found by experiment or observation, that causes no alteration of morphology, functional capacity, growth, development, or lifespan of the target organism distinguishable from those observed in normal (control) organisms of the same ...

How do you calculate no observed adverse effect level?

NOAEL (No Observed Adverse Effect Level), determined by toxicity studies etc., is divided by UFs (product of Uncertainty Factors)^*3 to convert it to human NOAEL. (e.g., mg/kg/day). ADI (Acceptable Daily Intake) and RfD (Reference Dose) are also used as terms having the same meaning as TDI.