That’s almost 17 times the recommended upper limit, and there are consequences to overconsumption.
Dr Gominak has done a bunch of research on D3 levels and sleep. Her RightSleep program will walk you through how to properly supplement into the ideal range. She has a few videos on YouTube with all the background info. This is my current favorite: https://www.youtube.com/watch?v=n1Qm5x7Lxgc
Having said that, most doctors don't have a clue about D3 dosing. You'll have to do some research.
Most people will overshoot in a month or two if they take 10,000 a day, but I know of people that have taken that level for long periods without ever going too high. It's super personalized.
It is also important to take K2 when you are taking higher doses of D3. Even if you have a higher than normal serum level, K2 mediates the metabolism of D3, and prevents issues. I've seen numerous examples of this, verified by CAC tests which consistently score 0 in people taking 10,000 IU of D3 with 100mg K2 for extended periods of time.
It seems like one issue is restless leg syndrome, but with an issue like that, you can just shoot high anad lower your dosage if you discover that to be an issue.
The unfortunate problem in the US is that those suffering most severely from many of the symptoms of vitamin D deficiency are often unable to obtain healthcare, so a lot of people out there are left to make guesses their own healthcare on issues like this. Getting vitamin D serum levels tested is a luxury reserved for those in first world countries.
Even if they're correct, it's hard to find any useful information here. They mention three numbers: 150,000 IU, 50,000 IU, and 4,000 IU. The 150,000 IU and 50,000 IU examples exhibited serious symptoms, but the number mentioned a few posts up is 10,000 IU. The 4,000 IU number is mentioned in the sentence, "A 2017 study found 3% of Americans took more than the tolerable upper limit of 4,000 IU daily for adults, thus putting themselves at risk for toxicity." But there's no discussion of what symptoms would be experienced at this level of toxicity.
As I said above, if it's just restless legs, it doesn't seem unreasonable to try the dose (10,000 IU) and lower it if you experience restless legs. Obviously it's better to get a blood test, but as I said before, not everyone has access to that kind of healthcare.
I also found it is backed by SNPedia, and that - at least with AncestryDNA - you can download a text file containing your sequenced DNA and then grep through it for specific things you are interested in from their wiki.
(I have no idea if that's in any way sensible, however...)
[0] https://promethease.com/ [1] https://www.snpedia.com/index.php/SNPedia
https://www.foundmyfitness.com/genetics
BTW, I also found my Vit D absorption efficiency is not good due to gene. The blood test corroborated the DNA report. So I supplement with 10K to raise the Vit D level.
It's very important to supplement with Vit K2 combined with mega dose Vit D. Otherwise there's risk.
If you have the money for a blood test, that will give you a good idea of what you might be missing. A DNA test can also direct you in a similar way. I just found out I might have an issue with converting b12 at the usual rate. This was found when i used my 23andMe raw output in some 3rd party websites.
If you really want to do things right, I think you should also pay attention to the bio availability of supplements. My understanding is that not all vitamins are made equal. This can lead to headlines dismissing the usefulness of supplementation altogether.
I try to focus on whole food supplementation when I need it. I personally take Athletic Greens at 1.5x the recommended dose, along with D3 as 10,000 IU (much higher than the base recommended dose because I live in the UK) and calcium (because I can't eat dairy).
[0] https://pubmed.ncbi.nlm.nih.gov/33549285/