Comment by Xunjin
It's unbelievable crazy what the author suggests, even say "10,000 IU if you're feeling daring / have darker skin / live in less sunny climates.".
Just a simple look at the side effects of high dosages:
Safety and side effects
Taken in typical doses, vitamin D is thought to be mainly safe.
But taking too much vitamin D in the form of supplements can be harmful and even deadly. Taking more than 4,000 IU a day of vitamin D might cause:
Upset stomach and vomiting.
Weight loss and not wanting to eat.
Muscle weakness.
Not being able to think clearly or quickly.
Heart rhythm issues.
Kidney stones and kidney damage.
Hi, author of the blog post here! Thanks for your concern. I do still stand by my claim, since more recent peer-reviewed studies have shown that up-to-10,000 IU is safe. As written in the post:
> McCullough et al 2019 gave over thousands of patients 5,000 to 10,000 IU/day, for seven years, and there were zero cases of serious side effects. This is in line with Billington et al 2020, a 3-year-long double-blinded randomized controlled trial, where they found "the safety profile of vitamin D supplementation is similar for doses of 400, 4000, and 10,000 IU/day." (though "mild hypercalcemia" increased from 3% to 9%. IMHO, that's a small cost for reducing the risk of major depression & suicide.)
So why then does Mayoclinic, etc, all say 4000 IU is the limit? I think because policy is decades behind science (this happened with trans fats), and also policymakers are much more risk-averse. (this is why in California, thanks to Prop 65, up until ~2018, there used to be a warning in every coffeehouse that coffee causes cancer.)
But thanks to your comment, I will edit the intro to note what the official max safe dose is, and that more recent peer-reviewed research shows it's too low!