Get your blood checked, get recommendation from a doctor... before supercharging your blood with calcium & other fun stuff...
I imagine someone reading this may not have healthcare coverage, but bloodwork can be cheap! Save up! Please be cautious
I did that for a little while (though the nurse practitioner at my work clinic wasn't too keen on signing off on non-medically indicated blood tests). IIRC, I was supplementing at 5000IU a day and after a few months wound up with a higher blood level than I was comfortable with, based on the ranges that came with the tests. After that, I reduced down to 2000IU a day or less.
I've been much less into supplements in general, but I only take 2000IU irregularly now.
https://www.devaboone.com/post/vitamin-d-part-2-shannon-s-st...
Her post about vit d in general:
https://www.devaboone.com/post/vitamin-d-part-1-back-to-basi...
Five years. Of 5000 IUs per day
Five years. Of more than 10x the EU RDA (and maybe 5x more than the US RDA, still)
But please tell me again how easy it is to overdose
And in another thread a guy was saying his daily D3 was 20,000 IU a day as if it was perfectly normal.
I was found to be extremely deficient in a blood test and personally been prescribed 10k UI, or maybe even 50k I can't remember, but it was a weekly tablet for only 6 weeks.
But since seeing the alarming articles on HN I reduced a bit, and I'm thinking of getting my blood tested.
If you do take Vitamin D, variant D3 is by far best, and it may be wise to take vitamin K2 as well to avoid calcium metabolism issues (calcification).
But due to fat solubility and therefore slow build up in the body, you are increasingly growing towards toxic levels over a long time.
The body can only regulate vitamin D before synthesis, after sunlight exposure. But if you take already-synthesized vitamin D, that regulation won't kick in and you're free to get hypervitaminosis.
Time in combination with individual biology are what brings issues here. Get blood work done (it cost me 30€ in Germany but was combined with 2 other tests).
I would be hesitant to go above 4000IU daily without monitoring blood levels every six months or so.
Its winter here in Canada, I'm taking 3000IU per day. I drop that to 1000IU in the summer. I'm not a doctor, not recommending you do the same. Just sharing.