Safety and side effects
Taken in appropriate doses, vitamin D is generally considered safe.
However, taking too much vitamin D can be harmful. Children age 9 years and older, adults, and pregnant and breast-feeding women who take more than 4,000 IU a day of vitamin D might experience:
• Nausea
• Vomiting
• Poor appetite
• Constipation
• Weakness
• Weight loss
• Confusion
• Disorientation
• Heart rhythm problems
• Kidney damage
https://www.mayoclinic.org/drugs-supplements-vitamin-d/art-20363792?pg=2
Yes, the scientific method (real competent studies) does say they might experience those side effects.
But they don’t.
I revere MDs who follow science and are experienced in treating human diseases and conditions. I seek them out and they heal and save.
But I have been disappointed by the medical community ignoring nutritional deficiencies as a cause of disease and ignoring minerals and nutrients as part of their cures and treatments.
The true way to take a therapeutic dose of D is to test and supplement and test again. Might take 6 months of 2 month dose adjustments to get it right. And some people require much more than 4000 IU a day even in sunny climes to get up to 60 in the blood levels.
I’m not a medical professional but I have seen how nutritional supplements can protect against even coming down with the flu so I feel I would be amiss not to mention it. And in flu season when no one is getting Beach degree sun onto their skin, taking 5000 IU for adult sized people is not going to cause those side effects.