The Vitamin D Council website advises taking 5,000 units of vitamin D a day, then testing the blood levels after 2 or 3 months of this, and adjust the intake up or down depending on the test results. It is hard to get much vitamin D from food, but some people get plenty from sunlight.

Have you ever tried taking msm? I'm curious how you react to it.

http://www.falconblanco.com/health/msm/msm.html