I don't know, but I take 5000 ius a day and because of my gastric sleeve I'm still somehow deficient. So upped it to 7500 ius by adding a multivitamin. I'm also

I don't know, but I take 5000 ius a day and because of my gastric sleeve I'm still somehow deficient. So upped it to 7500 ius by adding a multivitamin. I'm also O positive (which means I won the damn blood lottery for covid hehe), but overweight, so gotta hedge my bets as best as I can. I also take zinc.