@susan2018 I don't know if higher doses of Vit D3 will work for everyone with RLS, but it is such a benign supplement it seems worth a try. It seems to be recognized that up to 5000 IU is perfectly safe. I know people take much more than that but since it is not a water soluble vitamin and thus the excess is not excreted, it is best to first try the lower doses. If you are on medication and get break-through RLS, try the D3 in addition to your medication, and if it helps, you know you are on the right track.
One of my sisters had RLS and also had a low Vit D on a blood test so her MD had her get an injection. The RLS stopped and she mentioned it to the PA when she had a return visit and the PA told her it was because of the Vit D. So, now she takes 1000 IU each night and RLS has not returned. So, I too have RLS and started taking 1000 IUs of Vit D. It didn't do the trick so I began to increase the dose by 500 IUs a night. I got to 4000 IUs and that took care of it and has done so for a number of years now. And then another sister developed RLS and she went right to the 4000 IU and that took care of it. Our mother had severe RLS which would keep her pacing all night. She ended up on Gabapentin and another script which was a great help. I wish I had known about the Vit D back then as it certainly would have been worth trying.
Just as an aside, my Vit D was in the normal range both before and after I began taking the higher dose of D.
There is so much that medical science doesn't know about so many situations and very few MD's look at anecdotal reports and instead go to the medications recommended by the drug companies. Maybe Vit D won't help but maybe it will and what a benign resolution to this horrible syndrome. If my RLS returns, I will up the Vit D, but will discuss with my MD before exceeding the 5000 IU recognized safe limit. I know some people take 4 X that without adverse effects but I would want my MD checking my blood for a build up. I found the kind of rubbery capsules to be a better choice for me as I guess they might dissolve more quickly.
I wish you good luck in your search for relief from this horrible syndrome.