I do take it. When my attack began (end of May this year), my D level was pretty low: 25. The nurse practitioner I saw at the time had me take 50,000 IU weekly for three months.
After that, my neuro said to take 2,000 IU daily. Not that we should consider her word the gospel truth, trust me. But I think most doctors recommend 1,000-2,000 IU daily.