> It's pretty hard to get to toxic levels though, most people that don't live in a particularly sunny climate won't get anywhere near there on 5000 IU/day.

No, that’s literally what I was doing when I reached the excessive range: 5000 IU/day in winter with an indoor job.

This commonly repeated idea that everyone is deficient and you can’t overdose on 5000 IU/day is wrong.

> Just test your blood levels before you start and then after 3 months or so. It's quick and cheap, and the only way to know whether the dose is right.

Literally what I did.

Every time I explain this online it seems like the supplement people ignore what I wrote and just parrot the same “5000 IU/day and everyone is so deficient you can’t overdose” myth.

> No, that’s literally what I was doing when I reached the excessive range:

That doesn't make it easy for most people. In my case it was barely enough to move the needle, but that's not how it will be for most people either.

> you can’t overdose on 5000 IU/day is wrong

Of course you can (though it would usually have to be really prolonged to actually cause you troubles, and even then it's mostly due to calcium rather than vit D itself). The vast majority of people won't, but you don't know whether you're in that group or not until you test yourself.

> Literally what I did.

That's good, but my post obviously used plural "you" as a general advice.

(BTW. There's no evidence of toxicity below blood level of 150 ng/ml, but there are many guidelines that consider levels way below that, such as 50 ng/ml, as "too high" already)

It can also be at non-toxic levels but still cause arterial calcification.