Charles-Édouard Brown-Séquard was, by all accounts, a serious scientist.
He had studied the nervous system. He had made real contributions to neurology. He was a member of scientific academies in multiple countries. He had a reputation.
Then, in the spring of 1889, at the age of seventy-two, he decided to inject himself with a mixture of dog and guinea pig testicle juice, testicular vein blood, and semen.
Every day. For twenty days.
Then he published the results in the Lancet.
The Recipe
Let’s be precise about what Brown-Séquard was actually doing, because the specific ingredients are important context for understanding just how far scientific methodology had yet to travel.
His preparation contained:
- Testicular vein blood
- Semen
- Juice extracted from the crushed testes of dogs and guinea pigs
He injected one milliliter of this cocktail subcutaneously. Daily. Into himself.
After twenty days, he reported what he called a “radical change.” He wrote: "I had regained at least all the strength I possessed a good many years ago. I was able to make experiments for several hours. After dinner I was able to write a paper on a difficult subject. My limbs, tested with a dynamometer, gained 6 to 7 kg in strength. The jet of urine and the power of defecation became stronger."
He was reporting, in the Lancet, that injecting dog testicle extract made his urine stream more powerful.
The world was fascinated.
The Response
There are moments in the history of science when a paper lands and the world doesn’t say “that needs more evidence.” The world says “I’ll take twelve.”
This was one of those moments.
Brown-Séquard published his self-experiment report in June 1889, and within months, factories producing “extracts of animal organs by the Brown-Séquard method” had sprung up across Europe and America — including one, remarkably, operating next to Central Park in New York.
Thousands of patients were receiving injections of various animal organ extracts. Testicular preparations were the most popular, but the movement quickly expanded to include extracts from ovaries, thyroid, adrenal glands, and essentially anything a physician could get their hands on.
This explosion was called “organotherapy,” and it ran on the entirely reasonable-sounding logic that if a particular organ produced something vital, consuming that organ — or its extracts — should restore what was missing. The liver-sick man should eat liver. The man lacking vitality should eat testes.
The Roman physician Pliny had recommended the same thing centuries earlier. The logic never fully went away; it just took a famous self-experimenter to make it mainstream medicine for a couple of decades.
Why It Didn’t Work (And Why It Didn’t Matter)
Here’s the thing about Brown-Séquard’s preparation: it contained essentially zero biologically active testosterone.
The testes manufacture testosterone continuously, but they don’t store it. At any given time, roughly one kilogram of bull testes contains approximately six to eight milligrams of testosterone. When extracted, the hormone is immediately diluted into a complex biological soup of proteins, blood, and fluid — and then, even if any survived that process, injected testosterone in that form would be broken down rapidly.
Beyond the chemistry, testosterone that’s consumed orally — or injected in an immediately bioavailable liquid form — is largely inactivated before it can do much. The liver destroys it. What Brown-Séquard was injecting was, from a pharmacological standpoint, placebo.
What he experienced was the placebo effect — and a powerful one. A 72-year-old man who believes he’s receiving a vitality treatment, who is excited by the novelty of self-experimentation, who is monitoring himself obsessively for signs of improvement, will find them. The dynamometer readings went up. The urine stream felt stronger. The papers got written.
The human brain is extraordinarily good at finding evidence for what it expects to find.
The medical establishment noticed the scientific problems almost immediately. Harvey Cushing — one of the most respected neurosurgeons of the era — and Edward Rynearson, president of the Association for the Study of Internal Secretions, were so alarmed by the organotherapy craze that they coined the term "endocriminology" to describe what was happening to their young field.
Contemporary cartoons mocked the whole enterprise. Comic songs circulated. Respectable physicians worried openly about charlatanism poisoning the reputation of endocrinology before it had properly gotten off the ground.
The Accidental Contribution
Here’s the twist: Brown-Séquard may have done more to advance testosterone science through his quackery than through anything else he ever did.
The craze created enormous commercial demand. Pharmaceutical companies and legitimate scientists, embarrassed by what was happening in backyard clinics, were motivated to find the real hormone. The pressure to replace placebo with actual pharmacology drove the laboratory research that would eventually isolate testosterone.
Brown-Séquard died in 1894, five years after his famous paper, never knowing what he had accidentally launched. The factories closed. The extracts faded. The scientific search for the actual molecule that was doing all the things people believed testes could do — that search accelerated.
The old man with the dog juice didn’t find the answer. But he asked a question so loudly, so publicly, and so irresistibly that the people who would find the answer couldn’t ignore it.
What’s Next
Before we get to the chemistry of testosterone itself, we need to spend some time with a much older story — the millennia of human history in which men understood, empirically, exactly what the testes did, without knowing why.
Because the story of castration is not a footnote. It’s a 3,000-year experiment in human endocrinology.
