I've been taking Intact Digest for 13 months now. I don't think anybody inside, or outside of IFUS has any idea how much this"stuff" strengthens the immune system. It doesn't happen overnite, and some times you even wonder if it's doing anything. In the end, I'm a 60 year old feeling like I did 25 years ago, with a workout routine that rivals a 40 year old workout. I'm on it for life.