Whatever you do, when it comes to formula you should always use organic. Any food that your kids take should be healthy and organic food is the best one. It is really hard because in today's world everything is GMO. The best one is
hipp organic formula, I know a lot of parents that use it and no one has ever complained about it. You can find it everywhere, but buying it online is probably the best option for you. There are other good ones like Holle, you can try that one also, it will be good for your baby, but my favorite is Hipp.