Holle Bio Stage PRE formula is designed for infants aged 0 through 3 months old. It can be used either for babies who need to fully rely on formula for their nutrition or babies who just need it as a supplement to breastmilk in the early months of life. Once a baby reaches 3 months of age, they should transition either to Holle Stage 1 (for infants 0-6 months old) and then to Holle Stage 2 formula (for infants 6+ months old) to continue supporting their optimal growth and development.