MEDIUM formulas are designed for the “medium-sized dog” throughout their lifetime. Medium-sized dogs are famous for their energy, and were historically working dogs. Whether your medium dog is an indoor companion or spends time hunting outdoors, Royal Canin MEDIUM formulas help these dogs maintain natural defences throughout their life, while providing the balanced energy the medium dog needs to maintain a healthy weight. MEDIUM Puppy is for medium breed puppies up to 12 months old.