Formula choices

Emma • 💖10/12 💙06/15 👶 04/18
We're currently using Similac Sensitive for the boy. But he is having a hard time pooping. So we're going to try the newborn enfemil for him. It seems to be thinner. Is there a better kind yall know of? We're supplementing still so I'm trying to pick something that's easy on the tummy since the back and forth can bother them too.