There is no Recommended Daily Allowance (RDA) for boron since an essential biological role for it has not been identified. People consume varying amounts of boron depending on their diet. Diets considered to be high in boron provide approximately 3.25 mg of boron per 2000 kcal per day. Diets considered to be low in boron provide 0.25 mg of boron per 2000 kcal per day. The Tolerable Upper Intake Level (UL), the maximum dose at which no harmful effects would be expected, is 20 mg per day for adults and pregnant or breast-feeding women over 19 years of age.