What the PP said. It's just more nutrients, especially iron, but everything I've read said that babies can't even absorb the extra vitamins/minerals between 6-12 months (when they can technically start on follow on milks, though first stage milks are also meant to be used to 1 year). Beyond 12 months, your baby should be getting plenty of nutrients from a health diet of solid foods. It's just a gimmick so you don't switch to cow's milk. We won't be using them.