Abstract

Making human insulin by genetic engineering or by modifying pork insulin has been a great technical achievement. When we discussed human insulin in 1983¹ we concluded that it offered few advantages, except for the rare patient who was allergic or poorly responsive to animal insulins. Since then manufacturers have intensively promoted human insulins as ‘identical to the body’s own insulin and therefore the logical choice’ and ‘outstandingly pure and less immunogenic’ than pork or beef insulins, all but two brands of which have been withdrawn. But are these claims justified? If so, should diabetics already on beef or pork insulin change, and how is this best done?