I had a real struggle for years with very low Vitamin D. I tried several different prescription Vit D, and a number of different brands of OTC Vit D. None brought up my level adequately.

Finally, I tried Dr. Tod Cooperman's recommendation of Source Naturals Vitamin D-3 liquid drops, and it brought -- and has kept -- my level in the high-normal range. You hold it under your tongue for 30 seconds, then swallow. Pleasant, mild citrusy taste.

In the summer when I'm out in the sun swimming almost every day, my level goes up, and I just take fewer drops.