Insulin Belongs to the World

It's Monday, July twenty seventh. 105 years ago today, researchers in Toronto isolated insulin for the first time, turning a death sentence into a manageable condition almost overnight. Before insulin, a Type 1 diabetes diagnosis meant you had about a year to live, and the only treatment was a starvation diet that bought you a few extra months. The lead researcher, Frederick Banting, sold the patent to the University of Toronto for $1. He said, "Insulin does not belong to me, it belongs to the world." That quote is one of the most famous in the history of medicine, and the story of what happened to insulin after Banting let it go is one of the more depressing things I've looked into for this show. But before we get to the pricing, I wanted to start with a more basic question that I realized I couldn't fully answer: what is diabetes, actually? I know it has something to do with blood sugar and insulin, but I couldn't have explained the mechanism clearly until this week. And I had a personal reason to look into it, because diabetes is significantly more prevalent in South Asian populations than in almost any other group on Earth, and understanding why turns out to involve genetics, body composition, and a theory about ancient famines that's still being debated. The simplest way to think about it is this: every cell in your body needs glucose, which is a sugar that comes from the food you eat, to function. Glucose travels through your bloodstream, but it can't get into your cells on its own. It needs a hormone called insulin to unlock the door. Your pancreas produces insulin, and when everything works properly, insulin lets glucose into your cells, your cells get the energy they need, and your blood sugar stays in a normal range.

Diabetes is what happens when that system breaks. There are two main types, and they break in different ways. Type 1 diabetes, which accounts for about 3 to 5 percent of cases, is an autoimmune condition where your immune system attacks and destroys the cells in your pancreas that produce insulin. Without those cells, your body can't make insulin at all, which means glucose builds up in your blood while your cells starve. Type 1 usually develops in childhood and requires daily insulin injections for the rest of your life because there's currently no cure and no way to regenerate the destroyed cells.

Type 2 diabetes accounts for roughly 97 percent of all cases and works differently. In Type 2, your pancreas still produces insulin, but either your cells have become resistant to it, meaning the key doesn't fit the lock as well as it used to, or your pancreas can't produce enough insulin to keep up with the demand. Type 2 develops more gradually, is strongly influenced by diet, physical activity, and body composition, and can sometimes be managed or even reversed through lifestyle changes, though many people eventually need medication or insulin.

About 537 million adults worldwide have diabetes, and that number is projected to reach 783 million by 2045. In the United States, roughly 38 million people have it, which is about 11 percent of the population. It's the eighth leading cause of death globally and the leading cause of kidney failure, lower-limb amputations, and adult blindness in most developed countries. This is the part that got personal for me. South Asians are up to four times more likely to develop Type 2 diabetes than white Europeans, and they develop it five to ten years earlier. Between 15 and 20 percent of South Asians will be diagnosed with Type 2 diabetes in their lifetime, which is a staggering number when you consider that South Asia is home to roughly a quarter of the world's population. India alone has over 100 million people with diabetes, second only to China.

What makes the South Asian risk profile unusual is that it doesn't follow the pattern most people associate with diabetes. In Western countries, Type 2 diabetes is strongly linked to obesity: the heavier you are, the higher your risk. But South Asians develop diabetes at much lower body weights than Europeans. A South Asian person with a Body Mass Index, or BMI, of 22, which is considered healthy and normal by Western medical standards, has roughly the same diabetes risk as a European person with a BMI of 30, which is classified as obese. Researchers call this the "thin-fat phenotype": South Asians tend to have lower overall body weight but higher percentages of body fat, particularly visceral fat, which is the fat that wraps around your internal organs and is more metabolically active than the fat under your skin. You can look thin and still carry the metabolic risk profile of someone who is clinically obese.

The reasons for this are still being studied and debated. One theory, called the "thrifty genotype" hypothesis, suggests that populations with long histories of cyclical famine evolved to store energy more efficiently, which was a survival advantage when food was scarce but becomes a liability when food is abundant. Another theory focuses on differences in beta-cell function, the cells in the pancreas that produce insulin, suggesting that South Asians may have lower baseline capacity to produce insulin, which means even modest increases in demand from weight gain or diet changes can overwhelm the system faster. The genetic picture is complex, involving over 100 genes with individually small effects, and researchers haven't reached consensus on a single explanation. What is clear is that the standard medical guidelines for diabetes screening, which in many countries don't flag risk until a BMI of 25 or higher, may be missing South Asian patients who are already at significant risk at lower weights. On January 23, 1923, Banting, his colleague Charles Best, and their collaborator James Collip were awarded the American patent for insulin. They sold it to the University of Toronto for $1 each. Banting refused to put his name on the patent because he felt it would violate the Hippocratic oath to profit from a discovery that saved lives. The rights were then licensed to Eli Lilly so the company could mass-produce the drug and make it widely available. By 1923, insulin was the highest-selling product in Eli Lilly's history.

A century later, three companies, Eli Lilly, Novo Nordisk, and Sanofi, manufacture roughly 90 percent of the world's insulin supply. In 1996, Eli Lilly's Humalog insulin cost $21 for a month's supply. By 2019, the same drug cost $275, a 1,200 percent increase. The same vial that costs $275 in the United States costs about $55 in Germany. Americans cross the Canadian border to buy insulin at a fraction of the domestic price because the exact same product is sold for dramatically less in nearly every other developed country.

A Yale University study found that one in four insulin-dependent diabetics in America ration their doses because of cost, skipping injections or reducing amounts to make each vial last longer. Rationing insulin can lead to diabetic ketoacidosis, a life-threatening condition that sends roughly 750,000 Americans to the emergency room every year and kills thousands. Four out of five Americans with diabetes have gone into debt to pay for insulin. People have died because they couldn't afford a drug that the inventor sold for $1 because he believed no one should be denied access to it.

In 2023, Eli Lilly announced it would cap insulin costs at $35 per month for insured patients, and other manufacturers followed. The Inflation Reduction Act of 2022 capped insulin copays at $35 for Medicare recipients. These are real improvements, but they don't change the underlying dynamic: a drug that costs a few dollars to manufacture and was given away for $1 over a century ago is still priced at hundreds of dollars per vial at list price, and the three companies that control the supply have raised prices in near-lockstep for decades in what multiple lawsuits have alleged is coordinated pricing behavior. The part of this that I keep sitting with is the contrast between what Banting intended and what happened. He sold the patent for $1 because he believed a lifesaving drug shouldn't be owned by anyone. A hundred years later, three companies control 90 percent of the global supply and one in four Americans who depend on it can't afford to take the full dose. 537 million people worldwide have diabetes, South Asians are four times more likely to develop it than Europeans, and the drug that keeps millions of them alive costs a few dollars to produce and sells for hundreds. Banting said insulin belongs to the world. The world said it belongs to whoever can pay for it.

Stay informed, stay curious, and we'll see you tomorrow.