08/02/2026
The Boy Who Should Have Died — And the Injection That Changed Medicine Forever
Toronto General Hospital, January 1922.
A 14-year-old boy lay dying in a hospital bed.
His name was Leonard Thompson, and his body was slowly destroying itself.
He weighed 65 pounds.
His cheeks were hollow.
His ribs pressed visibly against thin, fragile skin.
His hair fell out in clumps.
The air around him smelled faintly of acetone — a sickly, sweet odor doctors recognized instantly. It meant one thing: his body had run out of fuel and had begun consuming itself to stay alive.
Leonard drifted in and out of consciousness, hovering at the edge of a diabetic coma.
Three years earlier, in 1919, Leonard had been diagnosed with Type 1 diabetes.
At the time, that diagnosis meant only one thing:
You will die.
When Medicine’s Only Answer Was Starvation
In 1919, there was no insulin. No treatment. No hope.
Doctors couldn’t stop diabetes — they could only slow it.
Their solution was something they grimly called “careful dietary regulation.”
In reality, it was starvation.
Leonard’s doctor restricted him to 450 calories a day — less than two small meals. Barely enough to keep a healthy child alive, let alone a boy fighting a catastrophic disease.
The logic was cruel but simple:
If sugar was killing him, he should eat as little as possible.
And for a while… it worked.
Not because Leonard was healing — but because his body was slowly wasting away instead of collapsing all at once.
Children with diabetes lived like ghosts under these starvation diets. Some lasted months. Some survived a year. Most didn’t.
Parents watched their children shrink.
They watched energy fade into weakness.
They watched life drain out of young bodies while doctors could only apologize.
By December 1921, Leonard Thompson was out of time.
A Father’s Impossible Choice
Leonard’s parents brought him to Toronto General Hospital, knowing what they would be told.
And they were told exactly what they feared.
Your son is dying.
There is nothing conventional medicine can do.
But then came a pause.
There was something else.
Something experimental.
Something dangerous.
Something that had never been tried on a human being.
Leonard’s father, Harry Thompson, listened as doctors explained it.
There was a young surgeon at the University of Toronto. His name was Frederick Banting.
He believed the pancreas produced a substance that controlled blood sugar — and that if it could be isolated, it might treat diabetes.
No one had ever proven it.
No one had ever injected it into a person.
Harry Thompson understood what this meant.
His son could die anyway.
Or his son could die sooner.
But there was a third possibility — one so unlikely it barely deserved hope.
Harry said yes.
The Crude Experiment That Shouldn’t Have Worked
Frederick Banting wasn’t a famous scientist. He wasn’t even particularly respected at first.
When he approached John Macleod, a senior professor at the University of Toronto, Macleod was skeptical.
Eventually, Macleod gave him:
A cramped laboratory
A handful of dogs
And a medical student assistant named Charles Best
That was it.
Through the summer of 1921, Banting and Best worked obsessively. They removed pancreases from dogs, induced diabetes, then injected them with crude pancreatic extracts.
And the dogs lived.
Blood sugar dropped.
Symptoms reversed.
Animals on the verge of death recovered.
Still, colleagues were doubtful. The extract looked like “thick brown muck.” Many believed it would never work in humans.
By January 1922, with biochemist James Collip refining the extract, they were ready.
Or as ready as desperation ever allows.
January 11, 1922 — The Injection That Failed
Leonard Thompson lay in bed as doctors prepared the syringe.
His father stood nearby, helpless.
The injection went in.
Nothing happened.
Leonard broke out in hives — an allergic reaction. His blood sugar barely moved. The extract was too impure.
The miracle did not come.
The room filled with a quiet, crushing disappointment.
They could have stopped there.
They could have declared the experiment too dangerous.
They could have written Leonard off as another tragic case.
Instead, they went back to the lab.
Twelve Days Against Death
For 12 days, James Collip worked almost without sleep.
He refined the alcohol extraction process.
Removed protein contaminants.
Concentrated the active substance.
While he worked, Leonard weakened.
His parents watched their son fade hour by hour, knowing this was likely his final stretch of life.
Then came January 23, 1922.
The Second Injection
The syringe went in.
This time, the change was unmistakable.
Leonard’s blood sugar plummeted to near normal levels.
The acetone smell on his breath faded.
His breathing steadied.
His eyes focused.
The medical chart recorded it simply:
“The boy became brighter, more active, looked better and said he felt stronger.”
But everyone in that room knew what they were witnessing.
A death sentence had been reversed.
The World Changes Overnight
Leonard received daily injections.
He gained weight.
His strength returned.
Color came back to his face.
By May 1922, he went home.
News spread around the world.
Parents flooded the University of Toronto with letters:
“My daughter is dying.”
“My son has weeks to live.”
“Please — can you send insulin?”
The demand was overwhelming. For a time, production even failed entirely.
It wasn’t until Eli Lilly partnered with the university later in 1922 that insulin could be produced at scale.
By 1923, insulin was being shipped across the world.
Children who would have died started living.
A Nobel Prize — And a Rare Act of Integrity
In October 1923, just 21 months after Leonard’s successful injection, the Nobel Prize in Medicine was awarded to Banting and Macleod — the fastest Nobel recognition in medical history.
Banting was furious that Best had been excluded. He shared his prize money with him immediately.
Macleod did the same with Collip.
They all understood the truth:
This breakthrough belonged to collaboration, persistence — and one dying boy.
Leonard’s Life, And His Legacy
Leonard Thompson lived 13 more years on insulin.
He grew up.
He lived a relatively normal life.
He reached adulthood — something that would have been impossible in 1919.
On April 20, 1935, Leonard died of pneumonia at age 27.
Without insulin, he would have died at 14.
Insulin gave him time.
Time to live.
Time his parents never thought they’d have.
Why Leonard Thompson Still Matters
Today, millions of people live full lives with Type 1 diabetes.
They use insulin pens.
Pumps.
Continuous glucose monitors.
They go to school.
Build careers.
Fall in love.
Have children.
Every single one of them owes their life to a boy who was willing to be first.
Leonard Thompson was the bridge between a world where diabetes meant death — and a world where it could be managed.
Not because of certainty.
But because of hope.
Because a father said yes when the alternative was burying his child.
Because scientists kept going after failure.
Because one boy took a risk that changed medicine forever.
Remember His Name
Leonard Thompson
1907–1935
The first human to receive insulin and live.
Because he went first — millions got to live.
