my newborn was taking Similac Advance, but started to get fuzzy at nights. It became that she would get fuzzy and cried for three or four hours at nights. We took her to see her doctor. After checkup, the doctor said that she had gas from the formula, advised us to mix formula with Similac Alimentum, changed the regular glass bottles to Dr. Brown's, and prescribed her the gas medication. After the changes, she has been sleeping much better during the nights.