Similac Advance Stage 1 and Stage 2 are formulated for different developmental stages of infants. Stage 1 is designed for newborns up to 12 months, providing essential nutrients for growth and brain development. In contrast, Stage 2 is suitable for infants aged 6 to 12 months, featuring additional iron and vitamins to support their growing needs. Choosing the right formula is crucial for your baby’s health and development, making Similac a trusted option for parents.