[stooliepidgin]

And no to that too. RDAs try to be one-size-fits-all guesstimates.

For Vitamin D3 in particular:

"The model developed for UL derivation was summarized in 1998 (IOM, 1998), and it acknowledged that the lack of data would affect the ability to derive precise estimates." [0]

Furthermore, an RDA and a UL doesn't work for D3 because the ranges across people don't harmonize to specific "safe" or "adequate" numbers for a given demographic. 1000 IU is too much for some people. [0]

Blood tests trump RDAs. I need over 10k IU per day, but this could cause hypercalcemia, calcification of tissues, and/or calcium kidney stones in other people.

0. https://www.nal.usda.gov/sites/default/files/fnic_uploads//T...