The History of Insulin and Diabetes Treatment

Let’s be real: it’s hard to imagine today, but a diabetes diagnosis used to come with a countdown. Before Insulin, especially for what we now call Type 1 Diabetes, the outlook was often grim.

This is the story of how Insulin moved diabetes care from desperate measures to something people could actually live with—and how that shift still shapes treatment now.

Introduction: The State of Diabetes Before Insulin

Long before modern labs and glucose meters, physicians recognized diabetes by its symptoms—extreme thirst, Frequent urination, weight loss, and fatigue. In the late 1800s and early 1900s, doctors increasingly connected diabetes to problems with the pancreas, but they didn’t yet have a reliable way to replace the missing hormone.

For many children and young adults with severe diabetes, the condition progressed fast. Without effective therapy, the body couldn’t use glucose properly, so it broke down fat and muscle for energy. That led to severe weight loss and, in many cases, Diabetic ketoacidosis—a life-threatening state that wasn’t well treatable at the time.

If you want a broader backdrop, this is one of those moments where the history of diabetes feels intensely human: families and clinicians trying anything that might extend life.

Early Treatments: Diet and Starvation Methods

Diet as the main “therapy”

Before Insulin, treatment focused heavily on restricting carbohydrates and calories. Some people were placed on extremely low-calorie regimens—often called “starvation diets.” The idea was straightforward: reduce sugar in the urine by reducing sugar intake.

Honestly, it was a brutal trade-off. These diets could sometimes reduce symptoms for a short time, but they often left people dangerously undernourished. Weight loss, weakness, and susceptibility to infections were common, and the approach didn’t address the underlying Insulin deficiency.

Why starvation diets couldn’t solve the problem

Severe Insulin deficiency isn’t just a “too much sugar” issue. Without Insulin, cells can’t access glucose effectively, and the liver releases more glucose and ketones. So even with tight food restriction, the metabolic storm could continue.

Eating patterns still matter in diabetes care today, but Insulin is what made adequate nutrition and long-term survival realistically compatible for many people with Type 1 Diabetes.

The Discovery of Insulin: A Breakthrough in 1921

In 1921, researchers in Toronto—most famously Frederick Banting and Charles Best, working with J.J.R. Macleod and biochemist James Collip—isolated an extract from the pancreas that could lower blood glucose in diabetic animals. The key was obtaining something that could replace what the diabetic body lacked.

The term “Insulin” comes from insula, Latin for “island,” referring to the islets of Langerhans in the pancreas, where Insulin is produced.

A lot of the popular narrative makes this sound like an overnight miracle. It wasn’t. Purification, dosing, and safety were major hurdles. Still, compared with what came before, it was an enormous leap—one of the most important discovery of Insulin stories in medical history.

For manufacturer and research timelines, plus modern Insulin background, Novo Nordisk also maintains educational material and historical context here: https://www.novonordisk.com.

First Human Use: Leonard Thompson’s Life-Saving Injection

In early 1922, Leonard Thompson, a 14-year-old boy with severe diabetes, became the first person to receive Insulin injections in a clinical setting. The initial injection used a crude extract and caused side effects. After further purification, Leonard received Insulin again, and his condition improved dramatically.

That moment is often described as the turning point where diabetes care moved from “we can only slow this down” to “we can treat this.” That’s a win—while also being a reminder that early Insulin therapy was still new, imperfect, and demanded careful observation.

How Insulin Changed Diabetes Management Globally

Insulin didn’t “cure” diabetes, and it didn’t erase risk. But it did change the entire trajectory of the disease.

For Type 1 Diabetes, it transformed survival. For many people with Type 2 Diabetes, Insulin later became an important option when the body couldn’t meet its needs with lifestyle changes and other medications.

Over time, Insulin production and formulations evolved—from early animal-sourced Insulin to highly purified human Insulin and Insulin analogs. These advances aimed to improve predictability and flexibility, although individual responses vary.

Today’s diabetes care also includes better education, glucose monitoring (including CGMs), and clearer guidance on avoiding both Hypoglycemia and hyperglycemia. If you’re interested in big-picture progress, it’s fair to describe the last century as a series of Insulin treatment breakthroughs—with plenty of ongoing debate about access, affordability, and equity.

Conclusion: The Lasting Legacy of Insulin

The discovery of Insulin in 1921 didn’t just add a new drug to the pharmacy shelf. It rewrote what it meant to live with diabetes. Before Insulin, many patients—especially children with Type 1 Diabetes—had little chance of long-term survival. After Insulin, the conversation shifted to management, monitoring, and building a life.

If you’re tracking Insulin doses, carbs, and glucose trends for day-to-day management, Diabetes diary Plus can be a helpful starting point to keep everything in one place—especially when you want clean exports to review with your clinician.