The mold Hunter: The Man Who Saved Millions by Failing for a Decade

The incredible true story of Dr. Akira Endo, the Japanese biochemist who endured a decade of failure to discover statins in ordinary mold, revolutionizing heart disease treatment.

In the early 1960s, the world was facing a new kind of plague. It wasn't bacterial. It wasn't viral. It was internal.

Heart disease was quietly becoming the number one killer in the industrialized world. Arteries were clogging, hardening like old pipes packed with grease. Men in their 40s and 50s—seemingly healthy, productive members of the post-war boom—were dropping dead of massive heart attacks without warning.

Medicine had no answer. Doctors knew that high cholesterol was the culprit, a waxy substance building up in the blood. But they had zero tools to stop it. Telling a patient they had high cholesterol in 1965 was essentially telling them they were a ticking time bomb that no one knew how to defuse.

The prevailing scientific consensus was that cholesterol had to be managed through diet—starving the body of fats. It was a miserable, ineffective solution. The human liver is an incredibly efficient machine; if you don't eat cholesterol, the liver just makes more of it. The body was fighting itself, and the body was winning.

Into this landscape of medical impotence stepped Dr. Akira Endo.

Endo was a biochemist at Sankyo, a Japanese pharmaceutical company in Tokyo. He was not a rock star scientist. He was a quiet, methodical man who grew up on a farm in northern Japan, fascinated by the mushrooms and molds that grew in the damp earth. While other kids looked up at the stars, Endo looked down at the rot.

He had a theory that sounded, to his superiors, borderline insane. He believed the answer to the modern plague of heart disease wasn't in a high-tech chemical synthesizer. He believed it was in fungus.

His logic was deceptively simple, born of a farmer's observation. Bacteria require cholesterol to build their cell walls, just like humans do. Fungi and bacteria are natural enemies, fighting a microscopic war for territory in the soil. Endo reasoned that over millions of years of evolution, fungi must have developed a weapon to kill bacteria—perhaps a chemical weapon that starved the bacteria by stopping them from producing cholesterol.

If he could find that weapon, perhaps he could use it to stop the human liver from overproducing cholesterol, too.

It was a brilliant hypothesis. It was also a logistical nightmare. There are millions of species of fungi on Earth. Finding the right one was worse than finding a needle in a haystack; it was like finding a specific grain of sand on a beach, and having no idea what the grain looked like.

When Endo presented his plan to his bosses at Sankyo, they were underwhelmed. Developing a drug from mold was old news—Alexander Fleming had done it with penicillin decades earlier. The pharmaceutical world was moving toward synthetic chemistry, designing molecules from scratch in a lab. Endo wanted to go dumpster diving in nature.

They gave him a small team, very little funding, and a corner of a lab. It was the kind of assignment given to someone the company doesn't expect much from.

The grind began in 1971.

It is hard to describe the sheer, crushing monotony of scientific research when it isn't working. Movies show the "Eureka" moment. They don't show the ten years preceding it.

Endo’s life became a cycle of cultivation and disappointment. He would collect samples of soil, rotting fruit, and damp wood. He would isolate the molds growing on them. He would brew them in huge vats, creating a foul-smelling fungal soup. Then, he would extract the chemical compounds produced by the mold and test them against cholesterol-producing enzymes in a test tube.

Test number one: Failure.

Test number ten: Failure.

Test number one hundred: Failure.

Months turned into years. The lab smelled permanently of yeast and decay. Endo’s colleagues began to pity him, then ignore him, then quietly mock him. He was the "mold guy," wasting the company’s money on a childhood obsession. In the highly pressured, conformist culture of a Japanese corporation, being the outlier who produces zero results is a kind of professional purgatory.

Endo didn't care. He possessed a quality that is far more important in science than raw intelligence: a superhuman tolerance for drudgery. He was obsessed with the truth hidden in the dirt.

By 1973, he had tested 2,000 different fungal strains. Nothing worked.

His team began to lose heart. The pressure from management to shut down the project was immense. Why keep throwing money into a hole? Why not work on something with immediate commercial potential?

Endo kept going. 3,000 tests. 4,000 tests. 5,000 tests.

He was working late nights, weekends, holidays. His eyes burned from staring into microscopes. His hands were stained with chemical reagents. He was a man possessed by a possibility that only he could see.

By 1975, he had tested 6,000 distinct strains of fungus. Six thousand times he had hoped, and six thousand times he had been wrong. It was a marathon of failure that would have broken almost anyone else.

And then came sample number 6,365.

It was a common blue-green mold called Penicillium citrinum, the kind you might find growing on a forgotten orange in the back of your fridge.

Endo ran the standard tests. He introduced the compounds from the mold into a test tube containing the enzymes responsible for creating cholesterol.

Usually, the enzymes would just keep working, churning out cholesterol regardless of the mold broth. But this time, something happened. The enzymatic action stopped cold.

Endo didn't shout. He didn't pop champagne. In science, the biggest moments are usually marked by a quiet confusion. He assumed he had made a mistake. He assumed the sample was contaminated, or that the mold was simply toxic and had killed everything in the test tube.

He ran the test again. The same result.

He isolated the specific compound responsible. He named it ML-236B.

Now came the real test. He had to see if it worked in a living creature, not just a test tube. He injected the compound into rats.

It failed miserably. The rats’ cholesterol levels didn't budge.

It was a devastating blow after years of work. The compound worked in theory, but not in practice. His bosses were ready to pull the plug finally. Six thousand tests, one glimmer of hope, and then a dead end.

But Endo couldn't let it go. The biochemistry in the test tube had been too perfect. Why did it fail in the rats?

He spent weeks agonizing over the data, reviewing everything. Then he realized something that everyone else had overlooked. Rats have a very different metabolism than humans. Their bodies are designed to clear cholesterol incredibly quickly. The drug was working, but the rats' systems were overriding it almost instantly.

He needed a better animal model. He needed an animal whose metabolism more closely resembled a human's.

He needed chickens.

Chickens, specifically hens, have very high cholesterol levels because they need it to produce egg yolks. Endo managed to secure a flock of hens. He began administering ML-236B to them.

The results were staggering. The cholesterol levels in the hens' blood plummeted by nearly 50%.

It was real. After a decade of digging through rot, Akira Endo had found the holy grail of cardiology. He had discovered the first "statin."

The story should end here with ticker-tape parades and a Nobel Prize. But real life is rarely that neat.

Discovering the drug was only half the battle. Getting it to the world was the other half, and it was just as brutal.

When Sankyo finally began human trials years later, the results were miraculous. Patients with dangerously high cholesterol saw their numbers drop to normal ranges within weeks. It was a medical magic bullet.

But then, disaster struck again. In long-term toxicology studies in dogs, the drug appeared to cause cancerous tumors at extremely high doses.

Panic set in at Sankyo. The shadow of the Thalidomide tragedy—where a morning sickness drug caused horrific birth defects—still hung over the pharmaceutical industry. No company wanted to be responsible for a drug that caused cancer.

In 1980, just as the finish line was in sight, Sankyo shut down the entire project.

Endo was crushed. Ten years of failure, followed by a brilliant success, only to have it snatched away by corporate fear. He was sidelined within the company, a man who had flown too close to the sun.

For years, the miracle cure sat on a shelf, gathering dust in a Tokyo archive. Endo watched as millions of people around the world continued to die of heart attacks that could have been prevented.

But the genie was out of the bottle. Endo had published his early findings in scientific journals. Other scientists, and other drug companies, had seen the data. They knew Endo was right, even if his own company didn't have the stomach to see it through.

In the United States, researchers at Merck took Endo’s blueprint. They found a similar fungus, isolated a similar compound, and began their own development. They refined it, ran their own trials, and proved that the initial cancer fears in dogs were unfounded at human distances.

In 1987, Merck released lovastatin, the first commercially available statin drug.

It changed the world instantly. Suddenly, doctors had a weapon. Heart disease mortality rates began to drop for the first time in modern history. Statins became one of the most widely prescribed classes of drugs on the planet, generating billions of dollars in revenue and, more importantly, saving tens of millions of lives.

Akira Endo did not get rich from this. He did not become a household name. For decades, he was largely a footnote in the history of the drug he discovered. He remained a salaried employee at Sankyo until his retirement, living a modest life.

It wasn't until decades later, as the sheer scale of the statin revolution became clear, that the scientific community turned back to look for the man who started it all. He began to receive awards in his old age, recognized finally as the father of modern cardiovascular medicine.

But those who knew him said he never cared about the accolades. He was never motivated by the desire to be a hero.

He was motivated by the puzzle. He was motivated by the unbearable reality of a disease that was killing people in their prime, and the stubborn, almost irrational belief that the answer lay in the dirt beneath his feet.

Akira Endo’s story is a testament to the power of the invisible grind. We live in a culture that celebrates the fast track, the "30 Under 30," the overnight success. We want results now.

Endo’s life proves that some of the most profound changes in human history come from people who are willing to endure decades of silence, failure, and ridicule. It proves that sometimes, the only difference between a crazy idea and a world-changing discovery is the willingness to test sample number 6,365.