Earlier quoted context omitted.
Its also been shown not to have an effect in at least one RCT, but the problem is social media skews against spreading that information (its kind of a downer so it won't get shared so much) https://www.medrxiv.org/content/10.1101/2020.11.16.20232397v... (Yes, the RCT uses cholecalciferol instead of calcifediol, so the reason why the intervention did not work may be that its a bit late. Yes, the Spanish trial had extr…
So even just looking at these two studies, and the relatively safety and low cost of Vitamin D, why wouldn't you take it?
My point is that its important for people to have an accurate picture of what is the probability of it working, to have a good "feel" of what the likelihood of a good outcome is. Unfortunately social media is providing a skewed picture.
I'm not sure what mechanism would ensure that people get an accurate picture.