Various types of veterinary insulins are known as PZI, "Protamine Zinc Insulin" . The ones we use most often for animals are a combination /beef-derived insulin or a -derived insulin. Because most are veterinary insulins, PZIs are not available at normal human pharmacies. The only PZI insulin still available for people is CP Pharma's Hypurin Bovine Protamine Zinc and it must be imported from the UK.