Right now, Lila, I am taking 10,000 iu. Yes, you read that correctly! Since I was extremely difficient, my dr started me at 4,000iu, which did nothing... After reading more than a couple books and papers, I upped my dose to 8,000iu. That's when things started happening, ie: the pre-cancers started healing and disappearing. Most researchers agree that 8,000iu is a good 'maintenance' dose and I needed therapeutic. At that point, I decided to add more. I have kept my dr appraised of my experiment and he has no problem with it. (I have had several blood tests.) He just says, 'Keep taking it". From his remarks the last time I went, he has become a believer. I am toying with the idea of doing an even higher dose for several months, maybe. I even have a new improvement to celebrate. At about 7 yrs old, I managed to grind the tip of my right index finger almost to the bone (man, that smarted). I have a normal nail (sort of) but the skin was very thick, lumpy and caloused, with impaired sense of touch. None of this was ever a problem but I had done some permanent damage. The peculiar skin would grow up my nail and pull away, leaving me with a 'cut' under my nail. I would have to remove it. Nothing improved the reduced sense of touch. Well, now it has started to heal!!!! The skin has thinned, flattened and I can now feel more than I ever can remember. It looks and feels almost like normal skin. It isn't even noticeable to others anymore. I am simply stunned, to say the least. This is the second skin injury that has healed like this for me but the first that was over fifty years old. I am also feeling more movement in my 'frozen toe'. That's calcium that must be disolving. I'll keep you posted on it's progress. Needless to say, I highly recommend D3, if you are deficient and most are. I also take mine with Vit K2.