I'm not familiar with those probiotics from GNC. Supposedly Natren is a good brand. But I personally like getting probiotics from cultured fermented foods like sauerkraut and kefir. Homemade is best. You can check out the book "Wild Fermentation" if you're interested in making your own. As far as consuming "too much" probiotics from cultured food...I think that would be difficult to overdose on.