Two men and $3 changed the course of diabetes treatment. In 1921, Canadian scientists Frederick Banting and Charles Best discovered insulin—a development that altered the outlook for people living with diabetes. Because this discovery could save lives, Banting, Best, and James Collip, their colleague who purified the insulin, sold the patent to the University of Toronto for $1 Canadian each, with the hope that affordable insulin would become available quickly.

The scientists made it clear that their motivation was for the good of humanity rather than commercial profit. But in order to keep up with demand and produce insulin on a large scale, the University of Toronto signed nonexclusive licenses with medical companies such as Eli Lilly, which went on to produce enough insulin for all of North America by 1923—a move that opened the doorway to the privatization and commercialization of insulin.

In 2014, almost 93 years after the scientists’ gesture of goodwill, insulin was a $24 billion global industry—and it’s expanding fast. According to a report from P&S Market Research, by 2020 the global insulin market will top $48 billion.

Unfortunately, the cost to consumers is also rising, particularly for those who are uninsured or underinsured and those who need large total daily doses. While it’s easy to point blame at pharmaceutical companies for increasing prices, certain information about manufacturing costs and health insurance plan discounts is confidential, which makes it difficult to say how prescription drugs are priced.

And drug company profits aren’t a bad thing. A portion of that money goes back into research and development to innovate and create better insulin products for the future. But the question remains: What good are these new products if the people who need them can’t afford them?