Hi doydie,
I was just tested for the first time in my life for Vitamin D. The level ranges from 32 to 99. Mine was 25 eek! I was on 1000 IU's a day. It was not enough so the Endo doc said, take 2000 IU's a day. Now it is only 33. Barely up to what some people get it to.

I can only take Vitamin D the plain one, the best is D3 I hear. D3 hurts my stomach (I have a stomach disorder) so I have a problem.

Have you been tested?

It depends where you live (closer to the equator and warmer climates), how much you get out in the sunshine, if you have light or darker skin, if you block with sunscreen the rays you need for your body to make its own Vitamin D.

Vitamin D I don't think will bother you the way you are thinking. Are you thinking of Magnesium? Too much of that will affect your bowels.

Someone like Mrs D will come and help answer your question I just quoted my problem too.