Reply To: I am a 65 year old male that has had Prostate Cancer and removal of the prostate via DaVinci robotic surgery. It was completed two years ago. My PSA tests show increases over the course of the past year……0.04 to 0.10 to 0.11 and to 0.14 in readings. I have self-medicated and take Vitamin D3 and Vitamin K2 in hopes of slowing down the growth of cancer cells. I will NOT take chemo-therapy nor radiation. Just how much of the Vitamin D3 can I safely take per day? I am currently at 15,000 IU daily and 300 mcg of the Vitamin K2 to off-set the calcification effects of the D3.