I was taking 5000 IU daily, then decided to just take 7 of the little pills once a week. Found this D3 10,000 IU, and now I take 4 one day a week. If I'm exposed to someone who is obviously sick with a cold or Flu, I'll take 50,000 IU as soon as I get home, then again at bedtime, then again in the morning. I've been doing this since 2009 and I've not been sick. Same with my hubby, and he used to get sick 3-4 times a year since childhood. We also take K2 since I understand it is important to take with the D3