Cheryl
My cardiologist and my endocronolgist both recommend that I take 4000 IU a day of Vitamin D. That dosage has been confirmed by my 3 Vitamin D blood tests a year to put my vitamin D level at the right mark on the accepted lab values.
Again, my recommendation is to get a Vitamin D blood test, that's the best way to see if you are getting enough Vitamin D or if you need supplementation.

Charm