Recently, I went shopping for vitamin D supplements and I was surprised by the very wide range in products marketed for daily usage, going from 600 IU to 12,000

Recently, I went shopping for vitamin D supplements and I was surprised by the very wide range in products marketed for daily usage, going from 600 IU to 12,000 IU. The recommended intake and upper limit vary depending on which country's ministry of health or which non-governmental health organisation you ask. The Mayo Clinic places toxicity at 50,000 IU [1] and there is anecdotal evidence (i.e. unverifiable comments from the EFSA public consultation on vitamin D) of individuals taking up to 100,000 IU a day. [1]: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/vitamin-d-toxicity/faq-20058108 https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h...