HumaPen insulin injector

Humulin was the world's first approved genetically engineered human therapeutic. It is insulin that is made by bacteria but chemically and physically identical to insulin produced by a human pancreas. Human insulin is used daily by millions of people who live with diabetes and are unable to make their own insulin. It replaces therapeutic insulin derived from cattle and pigs, both of which have adverse side effects in some people. Insulin has been injected subcutaneously to treat diabetes since 1938.