Doctors can't prescribe anything without actually consulting with a patient, but when the top infectious disease guy tells us he's taking 6000 iu per day, you would have to be a moron to ignore that. I actually take about 8000 iu per day, because a high (but still safe) level is better for MS: Symptom-free for years!

Some doctor in South America used D3 supplements to get MS patients up to 250 ng/ml. They had to very strictly limit their calcium intake so they didn't get organ calcification, but I think all of them had their MS symptoms disappear. Bad stuff can happen at over 150 ng/ml long-term, so this is not recommended, but it's very interesting for MS researchers. I measure my level twice per year: It's under 100 ng/ml, I take no calcium supplements, and I do take Vitamin K2 to keep excess calcium out of my organs.

We're flying electric helicopters on Mars yet you can't turn on your clothes dryer in Texas. That's because scientists are in charge of Mars, and Republicans are in charge of Texas.