Tolerable Upper Intake Level

The Tolerable Upper Intake Level, usually abbreviated UL, is the highest average daily intake of a nutrient that is likely to pose no risk of adverse health effects to almost all healthy people in a particular life-stage group. It is one of the Dietary Reference Intakes used to evaluate nutrient intake. As usual intake rises above the UL, the potential risk of adverse effects increases .¹

The UL is an upper reference level for assessing risk, not a recommended intake or a target to reach. Recommended Dietary Allowances and Adequate Intakes describe amounts intended to meet nutritional needs, whereas the UL addresses the risk associated with excessive intake. An intake above the UL does not mean that harm will necessarily occur. Susceptibility varies among individuals, and the UL is designed to protect nearly all people in the relevant healthy population .¹

ULs are established by evaluating evidence that links different levels of nutrient intake with adverse effects and by accounting for uncertainty in that evidence. They generally apply to long-term, repeated daily intake rather than to a single unusually high intake. Depending on the nutrient and the evidence used to set its UL, the limit may apply to total intake from food, water, fortified foods, and supplements, or only to particular sources such as supplements and fortified foods .¹

A UL cannot be established for every nutrient because sufficient evidence about adverse effects may be unavailable. The absence of a UL therefore does not mean that unlimited intake is known to be safe .¹