[DiabloD3]

Most likely the rest of their life.

5000 IU is largely the minimum effective dose for supplementation. The FDA still recommends less than half of this, and it is a shame.

Disclaimer: I take 5k IU a day due to the past 2 decades of research on the efficacy.

[thisislife2]

A doctor who has written a good series of article on Vitamin D advises to be cautious about taking it "for life" - https://www.devaboone.com/post/vitamin-d-part-2-shannon-s-st... ... See also How long does it take for vitamin D to work? - https://www.drugs.com/medical-answers/long-vitamin-d-work-35...

[DiabloD3]

The first link aligns with what I know about it: above 70 ng/ml is where side effects start happening. I stay below 70 with 5000, but for other people, they may need less or even more, depends entirely on where you live, and other factors that are known to burn through Vitamin D (such as being overweight or drinking caffeinated beverages or experiencing high stress).

Based research I've seen, for optimal wakefulness and cognitive ability, 50-60 is optimal, below 40 is too low, above 70 is too high.

You may have to adjust dosage over time to dial this in.

[hed]

It's amazing to get tested and thinking you're heavy dosing and when tests come back it turns out you're barely in the green (low).

[thisislife2]

In my case, with 8 doses of 60,000 IU / week, I am no longer deficient, but the blood test in the 9th week also revealed that I have slightly crossed the margin of safe levels (borderline toxicity) for Vitamin D.

[jelsisi]

Is this how you chose your username?