Psychedelic History: 🚴♂️ Bicycle Day - Celebrating the Birth of LSD
- Sascha Kuhlmann
- Apr 18, 2025
- 4 min read
Updated: Mar 9
On April 19, 1943, Swiss chemist Albert Hofmann deliberately swallowed 250 micrograms of a compound he had synthesized five years earlier and mostly forgotten. Within an hour, he could barely speak. He asked his lab assistant to take him home. Wartime fuel restrictions meant they had to bicycle.
That ride became one of the strangest journeys in scientific history.
The backstory
Hofmann first synthesized LSD-25 in 1938 at Sandoz Pharmaceutical Company in Basel, Switzerland. He was researching derivatives of ergot, a fungus that grows on rye. The goal was finding a respiratory stimulant. LSD-25 showed nothing interesting in animal tests. It got shelved.
Five years later, something made Hofmann revisit it. He called it a "peculiar presentiment." On April 16, 1943, while resynthesizing the compound, he absorbed a small amount through his fingertips and had to go home. He lay down and experienced what he described as "a not unpleasant intoxicated-like condition, characterized by an extremely stimulated imagination."
He suspected what had happened. The dose that affected him was extraordinarily small. Most drugs require milligrams or grams to do anything. This seemed active in micrograms, millionths of a gram.
Three days later, he decided to test his hypothesis.
4:20 PM, April 19, 1943
Hofmann chose 250 micrograms as a cautious dose. He was wrong. Modern researchers consider 100 micrograms a full psychedelic dose. He had taken two and a half times that.
By 5:00 PM, his lab notes became abbreviated: "Beginning dizziness, feeling of anxiety, visual distortions, symptoms of paralysis, desire to laugh." He asked his assistant to take him home. They got on their bicycles.
The streets of Basel warped. "Everything in my field of vision wavered and was distorted as if seen in a curved mirror." Familiar buildings became alien. He believed his neighbor was a witch. He thought he was dying, that the LSD had poisoned him. He thought he had gone permanently insane.
A doctor was called. He found nothing wrong except dilated pupils. No physical abnormalities. That reassurance helped. Gradually, terror gave way to something else.
"Little by little I could begin to enjoy the unprecedented colors and plays of shapes that persisted behind my closed eyes. Kaleidoscopic, fantastic images surged in on me, alternating, variegated, opening and then closing themselves in circles and spirals, exploding in colored fountains."
The experience lasted about twelve hours. The next morning, colors seemed unusually vivid. The world looked newly created.
What Hofmann actually discovered
LSD is structurally similar to serotonin, a neurotransmitter that regulates mood, perception, and cognition. This similarity lets LSD bind to serotonin receptors, particularly 5-HT2A, which appears primarily responsible for its effects.
Only one of four possible structural arrangements of the molecule (the d-LSD isomer) has psychoactive properties. This specificity highlights how precise the relationship is between molecular structure and what a drug does to your brain.
Hofmann had found the most potent psychoactive substance known: active at doses measured in millionths of a gram.
What happened next
By 1947, Sandoz was marketing LSD under the name Delysid for psychiatric research. They suggested two uses: as a way to induce temporary psychosis so researchers could study schizophrenia, and as an aid in psychotherapy to help patients access repressed material.
Throughout the 1950s and early 1960s, LSD research expanded. Over 1,000 clinical papers were published. About 40,000 patients received LSD in research settings. Results for treating alcoholism, anxiety in terminal patients, and mood disorders looked promising.
In 1958, Hofmann isolated and synthesized psilocybin and psilocin from mushrooms used in Mexican religious ceremonies. He kept expanding the toolkit for studying altered states.
Then it ended. LSD escaped the lab and became associated with the counterculture movement. In 1968, the United States outlawed it. Most countries followed. Legitimate research stopped for decades.
The cultural explosion
Timothy Leary, a Harvard psychology professor, became its vocal proponent. Ken Kesey and the Merry Pranksters held "Acid Tests," LSD-fueled parties with multimedia and live music that spread psychedelic culture through California.
The Beatles' experimentation with LSD changed how they recorded music. Albums like Revolver and Sgt. Pepper's Lonely Hearts Club Band used new recording techniques and song structures. Pink Floyd, Jimi Hendrix, and the Grateful Dead pushed further. New genres emerged: psychedelic rock, acid jazz, later psychedelic trance.
Visual art developed a distinctive aesthetic: vibrant colors, swirling patterns, complex geometric designs. This aesthetic spread through fashion, graphic design, and advertising.
The return
Research resumed in the 2000s after decades underground. Modern brain imaging showed how LSD decreases activity in the "default mode network," regions associated with sense of self, while increasing connectivity between brain areas that do not normally communicate.
Clinical studies investigated LSD for depression, anxiety, addiction, and PTSD. A 2014 study found LSD reduced anxiety in patients with life-threatening diseases when administered in therapeutic settings.
Silicon Valley embraced microdosing, tiny sub-perceptual doses meant to enhance creativity and problem-solving without hallucination.
Hofmann
He lived to 102. He watched his "problem child," as he called LSD in his memoir, become associated with recreational excess, then criminalized, then gradually reconsidered.
He maintained throughout his life that LSD, used with proper preparation and appropriate settings, could be valuable for understanding the human mind.
"I produced the substance as a medicine," he said. "It is not my fault if people abused it."
He died in 2008, seeing the beginnings of the psychedelic research renaissance.
Bicycle Day
Every April 19, people commemorate that strange ride through wartime Basel. Not just the discovery of a molecule, but the opening of a door: to neuroscience, to therapeutic applications, to questions about consciousness we still cannot fully answer.
Hofmann did not set out to change the world. He was curious about a compound he had shelved five years earlier. He followed that curiosity. Then he got on a bicycle.
References
Hofmann, A. (1979). LSD: My Problem Child. McGraw-Hill. Nichols, D. E. (2016). Psychedelics. Pharmacological Reviews. Pollan, M. (2018). How to Change Your Mind. Penguin Press. Carhart-Harris, R. L., et al. (2016). Neural correlates of the LSD experience. PNAS.
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