There have been cases of vitamin D poisoning in the past , not sure what the dosage was .
I would be very interested in reading about any such documented events. See what has been repeatedly proven is that there are NONE in the case of D3 ie cholecalciferol but there are a few in the case of D2 ie ergocalciferol. D2 of course is the synthetic, not natural version of Vitamin D that is provided by most (not all) doctors in weekly 50,000 IU shots (after being duped by Big Pharma or lured by the almighty $). This excerpt from vitaminDcouncl.org gives the best known example involving D3.
" the only documented case of pharmacological—not industrial—toxicity from cholecalciferol we could find in the literature was intoxication from an over-the-counter supplement called Prolongevity. Koutkia P, Chen TC, Holick MF. Vitamin D intoxication associated with an over-the-counter supplement. N Engl J Med. 2001 Jul 5;345(1):66–7. On closer inspection, it seemed more like an industrial accident but it was interesting because it gave us some idea of the safety of cholecalciferol. The capsules consumed contained up to 430 times the amount of cholecalciferol contained on the label (2,000 IU). The man had been taking between 156,000–2,604,000 IU of cholecalciferol a day (equivalent to between 390–6,500 of the 400 unit capsules) for two years. He recovered uneventfully after proper diagnosis, treatment with steroids, and sunscreen."
There are also cases of a person's D3 levels skyrocketing not from supplementation but from illnesses such as, hypersensitivity as with hyperparathyroidism which causes hypercalcemia and some carcinomas, non-Hodgkins lymphoma etc. Reportedly these can even occur when you have low levels of D3.
