I've been taking Twin Lab Daily One Caps for the past 11 years. The past 5 years, I have been taking the same vitamin but without iron. I am 52 yrs old and a body builder. I've taken all kinds of multiple vitamins prior to this. I've found that Twin Lab is the best multiple vitamin out there. In the last 11 years I've been taking Twin Lab, I have only contracted 2 colds. Before that on all the other melt-vitamins, I'd get a cold once a year. These vitamins are #1 on my list and I wouldn't substitute them for any other vitamin.