Yael, I'm not sure about synthetic probiotics, but with the In-Liven, which is organic, you can take up to the 4 teaspoons a day, I don't think there is a limit kwim? I think Kelly even said once that it is like telling someone not to eat brocoli, kwim? Chances are, if you are part of a study, that you may not even be in the group who takes the probiotics, but just the placebo.