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  • What Year Was Insulin First Used to Treat Diabetes? The Full Story

What Year Was Insulin First Used to Treat Diabetes? The Full Story

Diabetes
August 1, 2025
• 11 min read
Dhruv Sharma
Written by
Dhruv Sharma
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What year was insulin first used to treat diabetes?

If you or someone you love has diabetes, you’ve probably heard of insulin. It’s a life-saving hormone that helps people control their blood sugar. But have you ever wondered: What year was insulin first used to treat diabetes?

The answer is 1922 — a year that changed medicine forever.

Before insulin, a diagnosis of diabetes — especially type 1 — was like a death sentence. Children and adults wasted away, unable to eat, slowly losing weight, and often dying within months. There were no effective treatments. Doctors could only suggest extreme diets to slow the disease.

Then, in 1922, everything changed.

In this article, we’ll take you through the full story: who discovered insulin, how it was first used, why it was such a big deal, and what it means for people with diabetes today. We’ll keep it simple, clear, and packed with facts from trusted medical sources like the Mayo Clinic, the American Diabetes Association, the National Institutes of Health (NIH), and historical records from the University of Toronto.

Who Discovered Insulin and Why Was It Needed?

Before we get to the year 1922, it helps to understand what life was like for people with diabetes before insulin.

Diabetes Before Insulin: A Death Sentence

Diabetes isn’t a new disease. Ancient Egyptians wrote about a condition that sounds like diabetes over 3,000 years ago. People drank a lot of water, urinated constantly, and lost weight rapidly.

But until the 1900s, no one knew what caused it.

By the early 20th century, doctors knew that diabetes had something to do with sugar in the blood and the pancreas — a small organ behind the stomach. But they didn’t know exactly how to treat it.

The only “treatment” was a starvation diet. Doctors would put patients — often children — on a very low-calorie, low-carbohydrate diet. Some lived a little longer, but many still died. It was heartbreaking.

So, scientists were desperate to find a cure.

The Search for a Cure: Early Experiments

In the late 1800s and early 1900s, researchers began experimenting with the pancreas. They noticed that when they removed the pancreas from dogs, the animals developed diabetes.

This suggested that the pancreas made something that controlled blood sugar.

But what was that something?

Many scientists tried to isolate it. Some injected pancreas extracts into diabetic animals. A few saw improvements, but the results were inconsistent. The extracts were impure, hard to make, and often caused dangerous reactions.

The world needed a pure, safe, and effective treatment.

The Team That Changed Medicine: Banting, Best, Macleod, and Collip

The story of insulin’s discovery is one of teamwork, struggle, and determination. It all started with a young Canadian doctor named Frederick Banting.

Frederick Banting’s Big Idea

In 1920, Banting was a 28-year-old surgeon with a modest medical practice. He wasn’t famous. But he had a strong interest in diabetes.

One night, he read an article about the pancreas and had a sudden idea: What if the digestive juices in the pancreas were destroying the substance that controlled blood sugar?

He thought: if he could stop those juices, maybe he could extract the missing substance.

Banting wrote down his idea in just seven lines. That short note would lead to one of the greatest medical breakthroughs in history.

Moving to Toronto: The Start of the Experiment

Banting wasn’t a researcher, so he went to the University of Toronto and asked to work with Dr. J.J.R. Macleod, a well-known expert in carbohydrate metabolism.

At first, Macleod wasn’t impressed. But he gave Banting lab space, some lab animals (dogs), and a young medical student named Charles Best to help.

In the summer of 1921, Banting and Best began their experiments in a small, hot lab. They tied off the pancreatic ducts in dogs so the digestive parts would shrink, leaving the mysterious “islet” cells behind.

Then, they extracted fluid from those cells and injected it into diabetic dogs. The results were amazing: the dogs’ blood sugar dropped, and they became more active.

They called the substance “isletin” at first. Later, it was renamed insulin, from the Latin word insula, meaning “island” — because it came from the islets of Langerhans in the pancreas.

James Collip Joins: Making Insulin Usable

Banting and Best had proved insulin worked in animals. But it wasn’t pure enough for humans. It caused fevers and other side effects.

Enter Dr. James Collip, a biochemist. Macleod brought him in to purify the extract.

Collip developed a method to clean the insulin using alcohol and careful filtering. The result? A much purer, safer form of insulin.

Now, they were ready for human trials.

What Year Was Insulin First Used to Treat Diabetes?

Now, the moment we’ve been building to: What year was insulin first used to treat diabetes?

The answer is 1922.

More specifically, the first successful human use of insulin happened on January 11, 1922.

The First Patient: Leonard Thompson

The first person to receive insulin was a 14-year-old boy named Leonard Thompson. He was dying from type 1 diabetes.

At just 68 pounds (31 kg), he was weak, sick, and barely able to walk. His parents were told he wouldn’t live much longer.

On January 11, 1922, Dr. Charles Best and Dr. Edward Jeffrey, under the supervision of the research team, injected Leonard with a small dose of the experimental insulin.

The first try didn’t work well. Leonard had an allergic reaction because the insulin wasn’t pure enough.

But Collip improved the formula.

Twelve days later, on January 23, 1922, Leonard got a second injection — this time with purified insulin.

The results were dramatic.

His blood sugar dropped. He felt better. He gained energy. Within weeks, he was gaining weight and feeling like a normal teenager.

It was a miracle.

News spread fast. Other dying patients were treated. One after another, they improved.

For the first time in history, people with type 1 diabetes had hope.

How Did Insulin Change Diabetes Treatment?

Before 1922, diabetes — especially in children — was a death sentence.

After insulin, it became a manageable condition.

From Death Sentence to Manageable Disease

Imagine being told your child has diabetes in 1920. The doctor says, “There’s nothing we can do. Put them on a strict diet. Maybe they’ll live a few more months.”

Now imagine being told the same thing in 1923 — and the doctor pulls out a vial of insulin.

That was the difference insulin made.

Children who were weeks from death started eating again. They gained weight. They went back to school. Some lived for decades.

Insulin didn’t cure diabetes, but it gave people their lives back.

The First Commercial Insulin

By 1923, insulin was being produced on a larger scale.

The University of Toronto didn’t patent insulin for profit. Instead, they sold the rights to drug companies for just $1, with the goal of making it available to everyone.

Companies like Eli Lilly and Company began mass-producing insulin. They called it “Iletin” — the first commercial insulin.

Soon, insulin was being shipped around the world.

Why Was 1922 Such a Big Deal in Medical History?

The discovery of insulin in 1922 wasn’t just important for diabetes. It changed the entire field of medicine.

A New Era of Hormone Therapy

Insulin was the first hormone to be used as a treatment. It proved that hormones — chemicals made by the body — could be extracted, purified, and used to treat disease.

This opened the door for treatments for other hormone-related conditions, like thyroid disorders and growth problems.

Faster Medical Research

The insulin story showed that teamwork, funding, and university research could lead to real-world cures.

It encouraged more investment in medical science.

Nobel Prize Recognition

In 1923, Frederick Banting and J.J.R. Macleod were awarded the Nobel Prize in Physiology or Medicine for the discovery of insulin.

Banting was furious that Best was left out. In a powerful act of fairness, he shared his prize money with Best.

Macleod shared his with Collip.

It was a rare moment of humility and teamwork in science.

How Was Insulin Made Back Then?

You might wonder: how did they make insulin in 1922?

It wasn’t like today’s lab-made insulin.

From Animal Pancreases to Human Use

The first insulin was made from the pancreases of cows and pigs.

Scientists would collect pancreases from slaughterhouses, freeze them, and extract the insulin.

It was a messy, time-consuming process — but it worked.

This animal-based insulin was called “porcine” (pig) or “bovine” (cow) insulin.

For decades, this was the only type available.

Side Effects and Allergies

Some people had allergic reactions to animal insulin because it wasn’t exactly like human insulin.

Over time, doctors learned how to manage these reactions. But it wasn’t perfect.

Still, it saved lives.

How Has Insulin Changed Since 1922?

Insulin has come a long way since the first injection in 1922.

Human Insulin: Made in Labs (1980s)

In the 1980s, scientists used genetic engineering to create human insulin.

They put the human insulin gene into bacteria (like E. coli) or yeast. These tiny organisms then produced real human insulin.

This was a huge improvement. It reduced allergic reactions and worked more like the body’s own insulin.

Brand names like Humulin became widely used.

Insulin Analogs: Faster and Longer-Lasting

Today, we have insulin analogs — slightly modified versions of human insulin.

These include:

  • Rapid-acting insulin (like Humalog, NovoLog): Starts working in 15 minutes, great for meals.
  • Long-acting insulin (like Lantus, Levemir): Works slowly over 24 hours, keeps blood sugar stable.

These give people much better control over their diabetes.

Delivery Methods: From Syringes to Pumps

Back in 1922, insulin was injected with large, painful glass syringes and reused needles.

Today, people use:

  • Insulin pens: Easy-to-use, pre-filled devices.
  • Insulin pumps: Small machines that deliver insulin all day.
  • Inhalable insulin: A powdered form you breathe in (though less common).

Technology keeps improving.

What Types of Diabetes Can Be Treated with Insulin?

Not all diabetes is the same. But insulin helps several types.

Type 1 Diabetes: Insulin-Dependent

People with type 1 diabetes must take insulin every day. Their bodies don’t make any insulin because the immune system attacks the pancreas.

Without insulin, they can’t survive.

Insulin treatment is essential — just like it was for Leonard Thompson in 1922.

Type 2 Diabetes: Sometimes Needs Insulin

Most people with type 2 diabetes make insulin, but their bodies don’t use it well (insulin resistance).

At first, they may control it with diet, exercise, or pills.

But over time, many need insulin — especially as the pancreas gets weaker.

Insulin helps them keep blood sugar in a safe range.

Gestational Diabetes: Temporary Insulin Use

Some women develop gestational diabetes during pregnancy.

If diet and exercise aren’t enough, they may need insulin to protect the baby.

Insulin doesn’t cross the placenta, so it’s safe for the baby.

Other Types: Rare Forms

Some rare forms of diabetes — like MODY (Maturity-Onset Diabetes of the Young) — may or may not need insulin, depending on the type.

But for most people with insulin deficiency, insulin therapy is life-saving.

Who Was the First Person to Use Insulin?

We already mentioned Leonard Thompson — the 14-year-old boy who received the first effective insulin injection on January 23, 1922.

But let’s go deeper into his story.

Leonard Thompson: A Life Saved

Leonard was from Toronto. He was diagnosed with diabetes at age 11. By 1922, he was near death.

After the second insulin injection, he began to recover.

He gained weight. His energy returned. He lived for another 13 years — a huge victory at the time.

He died in 1935 at age 27 from complications of pneumonia, not diabetes.

His treatment proved that insulin could work in humans.

Other Early Patients

After Leonard, many others were treated:

  • Ted Ryder, a 15-year-old boy, received insulin in February 1922. He lived into his 70s.
  • Elizabeth Hughes, daughter of a U.S. Secretary of State, was one of the first Americans to get insulin. She lived to age 73.

These early success stories spread hope around the world.

How Did the World React to the Discovery of Insulin?

When news broke that insulin could treat diabetes, the reaction was massive.

Media Frenzy and Public Hope

Newspapers called it a “miracle drug.” Headlines screamed: “Diabetes Cure Found!”

Families rushed to hospitals, begging for treatment.

Doctors scrambled to get supplies.

But there wasn’t enough insulin to go around.

Supply Challenges

Making insulin was hard. It took thousands of animal pancreases to make a small amount.

The University of Toronto and Eli Lilly worked nonstop to increase production.

By 1923, insulin was available in many countries.

Ethical Decision: No Patent, Low Cost

The researchers made a bold choice: they refused to get rich from their discovery.

They sold the patent for $1 and demanded that insulin be affordable.

This decision saved millions of lives.

Imagine if insulin had been locked behind high prices. Many would have died.

Instead, it became a public good.

What Were the Risks of Early Insulin Treatment?

Even though insulin was a miracle, it wasn’t perfect.

Impure Extracts Caused Reactions

The first batches caused swelling, pain, and fever because they weren’t fully purified.

Some patients developed abscesses at injection sites.

Collip’s work helped fix this, but it took time.

Dosage Was Hard to Get Right

Doctors didn’t know how much insulin to give.

Too little? Blood sugar stayed high.

Too much? The patient could pass out from low blood sugar (hypoglycemia).

Many early deaths from insulin were due to overdoses.

Over time, better testing and training helped.

No Way to Monitor Blood Sugar

In 1922, there was no easy way to check blood sugar.

Doctors relied on urine tests — which were slow and inaccurate.

It wasn’t until later that blood glucose meters were invented.

Patients had to learn by trial and error.

How Has Insulin Improved Life Expectancy?

Before insulin, life expectancy for type 1 diabetes was months to a few years.

After insulin, it increased dramatically.

From Months to Decades

Children who once died within a year of diagnosis now lived into adulthood.

By the 1950s, many lived into their 30s and 40s.

Today, with modern insulin and care, people with type 1 diabetes can live into their 70s or beyond.

Quality of Life Improved

Insulin didn’t just extend life — it improved it.

People could eat more normally. They could go to school, work, have families.

Diabetes was no longer a prison.

Where Can You Learn More About Insulin’s History?

If you’re fascinated by this story, here are some great places to explore:

  • The University of Toronto’s Insulin Discovery Website: A detailed, accurate account of the experiments and people involved.
  • Diabetes Canada: Offers educational resources and historical timelines.
  • The American Diabetes Association (diabetes.org): Covers both science and patient stories.
  • The Nobel Prize Website: Features the 1923 award and speeches.

These sources are reliable and easy to understand.

Can You Still Get Animal Insulin Today?

You might wonder: is animal insulin still used?

Yes — but rarely.

Pork and Beef Insulin: Still Available

Some people still use porcine (pig) insulin, especially in countries where human insulin is expensive.

In the U.S. and Europe, most people use human or analog insulin.

Why Most People Use Human or Analog Insulin

  • Fewer allergic reactions
  • More predictable action
  • Better blood sugar control

But animal insulin is still a backup option for some.

What’s the Future of Insulin and Diabetes Treatment?

The story of insulin isn’t over.

Scientists are working on:

Insulin Pills and Patches

Right now, insulin must be injected or pumped.

But researchers are testing oral insulin (pills) and skin patches that deliver insulin through the skin.

These could make treatment much easier.

Artificial Pancreas

An artificial pancreas is a device that automatically monitors blood sugar and delivers insulin as needed.

It’s already available in some forms and keeps improving.

Cure Research: Stem Cells and Immunotherapy

Some scientists are working on curing type 1 diabetes by:

  • Replacing damaged insulin-producing cells with stem cells
  • Stopping the immune system from attacking the pancreas

These are still in testing, but they offer real hope.

Frequently Asked Questions (FAQ) on What year was insulin first used to treat diabetes?

Q: What year was insulin first used to treat diabetes?

A: Insulin was first successfully used to treat diabetes in 1922. The first effective human treatment happened on January 23, 1922, when 14-year-old Leonard Thompson received a purified insulin injection in Toronto, Canada.

Q: Who discovered insulin?

A: Insulin was discovered by a team of researchers: Dr. Frederick Banting, Charles Best, Dr. J.J.R. Macleod, and Dr. James Collip at the University of Toronto in 1921–1922.

Q: Who was the first person to receive insulin?

A: The first person to receive insulin was Leonard Thompson, a 14-year-old boy with type 1 diabetes. His successful treatment in January 1922 proved insulin could save lives.

Q: Was insulin available right after 1922?

A: Not immediately. At first, supply was limited. But by 1923, Eli Lilly and Company began mass-producing insulin, making it available to patients worldwide.

Q: How was insulin made in 1922?

A: The first insulin was made from the pancreases of cows and pigs. Scientists extracted and purified the hormone for human use.

Q: Did the inventors of insulin become rich?

A: No. The team sold the patent for $1 and insisted insulin be made affordable. They wanted it to help people, not make money.

Q: Can type 2 diabetes be treated with insulin?

A: Yes. While not all type 2 patients need insulin, many do — especially as the disease progresses. Insulin helps control blood sugar when other treatments aren’t enough.

Q: Is animal insulin still used today?

A: Yes, but rarely. Most people use human insulin or insulin analogs. However, some still use pork insulin, especially in low-income countries.

Q: What was the impact of insulin’s discovery?

A: It turned diabetes from a fatal disease into a manageable condition. Millions of lives have been saved since 1922.

Q: Are there side effects of insulin?

A: Yes. The main risk is low blood sugar (hypoglycemia). Other side effects include weight gain, injection site reactions, and rare allergies — especially with older animal insulins.

Q: How has insulin changed over time?

A: Insulin has evolved from impure animal extracts to pure human insulin made in labs, and now to advanced analogs that work faster or longer. Delivery methods have also improved — from glass syringes to insulin pens and pumps.

Q: Is there a cure for diabetes?

A: Not yet. But insulin and modern treatments allow people to live full, healthy lives. Research into cures — like stem cells and artificial pancreases — is ongoing.

Final Thoughts: A Miracle That Changed the World

So, to answer the question one more time: What year was insulin first used to treat diabetes?

The answer is 1922 — a year that saved millions of lives.

The discovery of insulin wasn’t just a scientific win. It was a human one. It gave hope to families, ended suffering, and showed what teamwork and compassion can achieve.

Today, people with diabetes live longer, healthier lives because of that breakthrough.

And while there’s still work to do — better delivery, lower costs, and hopefully one day a cure — we owe a huge debt to Banting, Best, Macleod, Collip, and Leonard Thompson.

They didn’t just discover a drug.

They gave the world a second chance.

Sources:

  • University of Toronto: The Discovery of Insulin
  • American Diabetes Association (diabetes.org)
  • Mayo Clinic: Diabetes Treatment: Insulin Types and Side Effects
  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
  • Nobel Prize Organization: The 1923 Nobel Prize in Physiology or Medicine
  • Diabetes Canada: History of Insulin
  • Eli Lilly and Company Archives

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