[colechristensen]

It's not hard to take too much.

They sell 5000 IU vitamin D pills, with regular supplementation my serum levels were at the top of the range which led me to ease off.

You can take too much and there are consequences, it screws with your calcium which eventually screws with your nerve firing.

[voldacar]

If you look at the literature on cases of D "toxicity" (hypercalcemia), it only really occurs when people take absurd doses like 100k IU per day (often far more) for months. This usually occurs by accident, rather than someone choosing to take that much. And since D toxicity isn't reported that often, I have to assume that there are a lot of people out there unwittingly taking mega doses but without developing toxicity. But everyone thinks that high doses of D are scary because of that idiotic 4000 IU number that gets thrown around. N=1, but I take 50k IU per day and have never had any issues. My calcium is within the normal range.

[colechristensen]

I would really hesitate to give the impression that you were giving medical advice like that, way out of range of that is considered safe.

[voldacar]

The range that is considered safe is much smaller than the range that is actually safe. It also doesn't help that there is misinformation about what "vitamin D toxicity" actually is.

Wikipedia states "Vitamin D toxicity, or hypervitaminosis D is the toxic state of an excess of vitamin D. The normal range for blood concentration is 20 to 50 nanograms per milliliter (ng/mL). However, the toxic state is known to be a value of 100 ng/ml or more in a clinical setting."

This is wrong because toxicity is not a pure function of vitamin D concentration. I'm above 100 ng/ml and yet my calcium is normal. The toxicity is purely a result of elevated calcium levels. The threshold level of D which causes this elevated level of calcium seems to vary significantly between individuals, and in any case, is much higher than the numbers that google or wikipedia gives you. At any rate the 4000 IU number is unscientific nonsense.

[jghn]

One of the claims is that what's considered normal range is already too low. I'm not personally equipped to tell you if that's right or wrong. But when people are suggesting to take megadoses they're coming from this angle, whether they realize it or not.