1. Mead Johnson Milk Powder Stage 3: Which babies are suitable? Mead Johnson milk powder stage 3 is designed for babies aged 6-12 months. Babies at this stage need more nutrients to support their rapid development. If your baby has started eating complementary foods and needs additional nutrition, Mead Johnson Milk Powder Stage 3 is a good choice. 2. Mead Johnson Milk Powder Stage 3: What are the benefits?