For Babies 0-12 Months. Do not add water. Excellent nutrition Closer to ever to mother's milk. Breast milk is best for babies. When a low-iron infant formula is desired, none is better than improved Similac. The most advanced Similac formula ever developed. The protein and fat in improved Similac make it closer than ever to breast milk. When using improved Similac, you may find that your baby's stools are softer, similar to those of breastfed infants.