Despite taking 10,000 units a day, I have come down with a cold, probably due to stress. I have Bio-Tech 50K IU capsules. In the past, I took just one at the first sign of a cold and that stopped me getting the cold. But this time, the cold is getting worse. I am thinking of taking 2 capsules and would like your opinion on this . By the way, I also take vitamin K2, zinc. boron, magnesium on a daily basis.