SIMILAC ISOMIL MILK FROM BIRTH ONWARDS 400GSIMILAC ISOMIL MILK FROM BIRTH ONWARDS 400G. For infants 06 months old, Similac Isomil 1 From Birth Onwards 400g is a premium milk formula. For women who wish to provide their infants with the finest nourishment possible, this product is ideal. The ingredients used to make Similac Isomil 1 have been carefully chosen to be kind to your baby's stomach. For infants with a cow's milk protein allergy or who are lactose intolerant, it's a great substitute.