Believe me, it certainly has worked for me. Many years ago before I got on to this regime of nutrients and vitamins I used to get an occasional cold, clogged sinuses, runny nose for about a week to ten day or so. After taking that stuff on a daily basis, knock on wood but I have not even had a cold. I also have to add that I lead a fairly healthy lifestyle as well.
I have had the same results too. Taking care of yourself pays back huge dividends.