I ignored my low vitamin D levels for years and believe that it contributed to my osteopenia and to developing breast cancer. My cousin uses this product and I borrowed it from her. The product is very well absorbed by the body and my D levels are now normal.. actually they are bordering on high. I'm the type of person that if one drop is good then 3 must be better.. not necessarily so, folks. This is has a good delivery system. Trust it.