Yes I also thought i was a fad. Whatever. I didn't even want to give it the time of day. But when my sister who gets sick easily (cough, colds, fever, etc.) startedtaking it she did not get sick! Hmm. "Fine." I agred to try it for my husband since I wasn't sure if I could since I am still breastfeeding.
Well, wow my husband, who also ALWAYS has colds, (bad colds) or felt weak, started NOT getting colds, had more energy etc. I was happy that the Amway Double X vitamins was worth it.
By the way, its a pack of 3 tablets that you have to drink twice a day. I know it seems a lot, but after I have experienced it first hand:

I was getting sick - cough, and a bad sore throat was starting. Quickly (after checking if I could drink it while breastfeeding), my husband told me to try taking the vitamins - Amway Double X. So I did. And wow. the next day, my sore throat was gone. SO now, after that I take it everyday and haven't gotten sick.
I shall update you in case I do. (I HOPE NOT THOUGH!)