I've been using S26 Gold since she was 3 months and has just switced, because I thought it was making her tummy loose. Now on NAN for a week and I think it's going better. She is also on some solids (ricecereal and veggies) now, so that could also be helping her loose tummy. I think that the Gold was maybe to rich. Actually my caregiver warned me against NAN, because it causes constipation in some bubs, but so far so good