In 1923, Frederick Banting, Charles Best, and James Collip sold the patent for insulin to the University of Toronto for $1 each because they believed such an essential medicine should be available to everyone who needed it.

The original patents for the insulin molecule have long since expired, but patents on parts of the production process — a strategy that has been famously used (and arguably abused) by drug companies — remain because pharmaceutical companies keep tweaking how they make it. Most insulins sold today are synthetic analogs that have been adjusted to last longer or act faster, which is one reason pharmaceutical companies give for why the cost of insulin has skyrocketed. These changes have prevented generic drug manufacturers from entering the market.