Tolerable Upper Intake Levels for US from https://www.ncbi.nlm.nih.gov/books/NBK56058/
Life Stage Group UL
Infants
0 to 6 mo 1,000 mg
6 to 12 mo 1,500 mg
Children
1–3 y 2,500 mg
4–8 y 2,500 mg
Males
9–13 y 3,000 mg
14–18 y 3,000 mg
19–30 y 2,500 mg
31–50 y 2,500 mg
51–70 y 2,000 mg
70 y 2,000 mg
Females
9–13 y 3,000 mg
14–18 y 3,000 mg
19–30 y 2,500 mg
31–50 y 2,500 mg
51–70 y 2,000 mg
70 y 2,000 mg
Pregnancy
14–18 y 3,000 mg
19–30 y 2,500 mg
31–50 y 2,500 mg
Lactation
14–18 y 3,000 mg
19–30 y 2,500 mg
31–50 y 2,500 mg