Reply To: Recently, I discovered that I seem to have a reaction to supplemental vitamin D3. A few days after I start taking it, my face gets flushed and I feel overheated….especially at night which disturbs my sleep. If I stop taking it these symptoms go away after a few days. I've tried several different brands thinking it might be some other ingredient. I've tried pill form and liquid form, all with the same results. I'm not supplementing with any Niacin. I'm sure it's the D that's causing this. I've searched elsewhere on the net but nobody seems to have any answers to this?? Also, I have a "Verilux" brand light that my doctor recommended to use in the winter to help improve my mood. Will the UV light from this help to increase my D levels at all? If so, what kind of exposure would I need daily to maintain normal levels? Any suggestions would be greatly appreciated!