Source?
https://www.mayoclinicproceedings.org/article/S0025-6196%281...
The one piece of evidence that these are all referring back to is a small study done in men in high latitudes in winter, when skin production of Vitamin D is decreased. It consisted of a small number of patients who were randomized to receive different amounts of Vitamin D, so only a small number actually got 10,000 units a day, the highest dose. And this was over a period of just 5 months. You can read the article here: https://pubmed.ncbi.nlm.nih.gov/12499343/
Note that the highest dose in this study was 10,000 units a day, which I would agree can be safe for some people over a short period of time. But it was not necessary in this study to attain goal Vitamin D levels, and over time that dose can definitely cause problems.
Also, where is the 50,000 to 100,000 unit evidence coming from? I'm not sure actually, since there are no human studies looking at that dose. This may be a "theoretical" dose based on studies in other animals, or a false extrapolation based on human studies.
> Moreover, the highest cumulative dose (657,000,000 UI) leading to toxicity was obtained after 36 months of treatment with cholecalciferol 600,000 UI/day
> 1mg will instantly kill you.
Figured people can Google, all I bring is awareness this is widely overblown, having taken myself, for therapeutic purposes, upwards of 100k IU per day for months without doctor supervision (but doing it correctly, with a very low calcium diet). People take vit D megadoses for autoimmunity, with significant success, but I'm not discussing this here.
As with anything fat-soluble it's wise to take it as part of a meal that includes plenty of fat.
The problem with most studies is, surely in part because of this unfounded fear, they are underdosed. I don't have anything on hand, but I know there are clinics supervising megadose vitamin D protocols all over the world, but mostly in Germany and Latin America, that I'm aware of.
I have been diagnosed with some autoimmunity issues and would love to try this. How did you identify that vitamin d might help with yours?
When I had my first major flare-up, I tested at 7ng/dl (near bottom half of the severe deficiency range). That's what lead me to pay attention to this subject.
You mean for compensating for the low vit D levels due to constant inflammation seen in autoimmunity? or to decrease autoimmunity? I have autoimmune diseases and my vit D goes down to about 7 ng/mL without supplementation, so I'm curious.
Per your question, the latter, the theory is autoimmunity is exacerbated in a certain genetic makeup, and to compensate for it by megadosing.
> Two patients, a Caucasian 90-year old man and a 95-year old woman, were monitored from 1 h up to 3 months after intake for clinical as well as biochemical signs of vitamin D intoxication. Blood vitamin D3 concentrations showed a prompt increase with the highest peak area already hours after the dose, followed by a rapid decrease to undetectable levels after day 14. Peak blood 25(OH)D3 concentrations were observed 8 days after intake (527 and 422 nmol/L, respectively (ref: 50–200 nmol/L)). Remarkably, plasma calcium levels increased only slightly up to 2.68 and 2.73 mmol/L, respectively (ref: 2.20–2.65 mmol/L) between 1 and 14 days after intake, whereas phosphate and creatinine levels remained within the reference range. No adverse clinical symptoms were noted.