ProfG has been urging people to ensure that you are vitamin sufficient.
He recommends the dose advised by the Vitamin D Council
This will maintain bone health and maybe, just maybe it will impact on your MS.
However some people have gone overboard and have found that to much of a good thing is bad.
Here is the case of an individual who was taking 10 times the vitamin D council dose.
Knowledge about complications of chronic ultra-high dose vitamin D supplementation is limited. We report a patient with primary progressive multiple sclerosis (MS) who presented with generalized weakness caused by hypercalcemia after uncontrolled intake of more than 50,000 IU of cholecalciferol per day over several months. Various treatment strategies were required to achieve normocalcemia. However, renal function improved only partly and further progression of MS was observed. We conclude that patients need to be informed about the risks of uncontrolled vitamin D intake and neurologists need to be alert of biochemical alterations and symptoms of vitamin D toxicity.
We know that Vitamin D (Cholecalciferol = Vitamin D3) and too much calcium don,t mix and this person had problems associated with too much calcification.
Dr Ruth has given words of wisdom on this but until is is visible I can't say what, so take these in moderation there is no solid evidence that it will impact your MS to any large extent and I would suspect that it will not based on the view that the immune response that deals with infection is not irradicated by Vitamin D supplementation