Upper level, universally abbreviated UL, is the highest average daily intake of a nutrient that is considered unlikely to pose a risk of adverse health effects to almost all healthy people. Set by expert committees from the dose-response evidence, ULs exist for vitamins and minerals where excess is harmful — vitamin A, vitamin D, iron, zinc, selenium, niacin, folate, and others. They are the ceiling of the dietary reference intake framework: below the recommended intake lies deficiency risk, above the upper level lies toxicity risk. ULs guide supplement formulation and fortification policy, preventing well-meant additions from pushing intakes into danger. They apply to chronic daily intake, not single meals.