“The article says at the end that >4,000 units a day can be unsafe.”
“According to the Institute of Medicine, 4000 IU is the safe upper level of daily vitamin D intake. However, doses up to 10,000 IU have not been shown to cause toxicity in healthy individuals. Vitamin D toxicity is generally caused by excessive doses of vitamin D supplements, not by diet or sun exposure.
Although vitamin D toxicity is a very rare condition, recent increases in supplement use may lead to an increase in reported cases. A daily intake ranging from 40,000–100,000 IU (1000–2500 micrograms), for one to several months, has been shown to cause toxicity in humans...”
https://www.healthline.com/nutrition/how-much-vitamin-d-is-too-much#TOC_TITLE_HDR_4
“One of the most popular doses currently is once-weekly 50,000 IU of ergocalciferol (D2). While this has gained popularity for its ease of use and fast results, we have seen several cases of vitamin D toxicity and related complications as a result of prescriber error, prescriber and pharmacy communication error, and longterm use of high-dose vitamin D.
One such case involved an 82-year-old white woman who presented with nausea and vomiting and was found to have hypercalcemia (14.1 mg/dL). Upon further history and work-up it was discovered that the patient had accidentally been taking 50,000 IU of ergocalciferol twice daily. How did this happen?
A prescription was inaccurately written for 50 IU twice daily. While we think this was intended to be 500 IU twice daily, the script was interpreted by the pharmacy as 50,000 IU twice daily. Her total 25-hydroxyvitamin D level at the time of diagnosis was 338 ng/mL. The time to toxicity was 5 months.”
https://www.amjmed.com/article/S0002-9343(16)31200-1/pdf
Very helpful thanks
It varies by the individual. My personal limit is 3000 IU daily without experiencing hypercalcemia. One of the symptoms is whole bone pain. I stick with 2000 IU and that is not every day. In my case, it was right thigh bone, a left ulna, and finger bone on left hand. It leaches calcium out of your bones and drops it in your bloodstream. The main ingredient in rat/mice poison if anyone wants to look it up. That is the mechanism of their death. MORE is not better.