Hormone therapies have been used since the early 20th Century and belong to a group of drugs that has recently become known as ‘biologics’. Biologics are medicinal products that have been produced by biological processes as opposed to chemically synthesized drugs. The term biologics spans a wide range of products that include therapeutics such as organs, tissue, cells, blood or blood components, vaccines and proteins. This ‘proteins’ subgroup can be further subdivided into therapeutics such as antibodies, enzymes and hormones. The first hormone therapeutics were extracted from human or animal sources; however, with the advent and development of cloning and protein production technologies from the late-20th Century onwards, protein hormone therapeutics are now produced by recombinant DNA technology.