REMEMBER to take this with vitamin K2 (mk7), about 200 mcg of K2 is needed everyday with every 50,000 D3!!!!!!! This D3-50 is awesome at chasing off colds, flus, pneumonia and Bronchitis for me within 3 days of starting it, I take 1000 units per pound of body weight everyday for three days, -thats right 200,000 3xs! I have emphysema and I can not let a cold take its course because in one day it progresses to pneumonia, but not anymore. Normally this just a once a week or twice a month dosage, my doctor wants me to take it three times per week but the corresponding K2 dosage I can not afford so I don't. Now, it MUST be taken along with vitamin K2 because K2 directs calcium in the body back in to the bones and all this D3 will have the calcium really flowing around and very ready to be absorbed by anyplace it can bind to - bad news for the brain and heart where it can harden the plaque in valves and arteries and extra calcium is a nightmare to the nervous system. So if you are not going to take K2 do not take D3 either. In nature the two vitamins come together in live fermented foods and fresh dairy but with the pasteurization process the K2 gets destroyed, so thats why you don't get enough in your foods to maintain good health