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When Is LSD day

When Is LSD day?

Giordano Novak

Giordano Novak

Medically reviewed by Giordano Novak, University of São Paulo on April 3rd 2022

Key Takeaways:

  • This day celebrates the discovery of LSD by Albert Hofmann on April 16, 1943.
  • It has been celebrated since 1966 and is now an international event commemorating LSD’s impact on history, culture, and the progress of science.
  • LSD Day is not just about partying and consuming the drug. It’s also a time for reflection and learning more about the science, history, and culture of psychedelics.


Do you ever find yourself wondering when LSD day is? Well, if so, then I’m here to tell you!

In the United States, LSD day is celebrated on April 19th every year. This date marks the anniversary of Hofmann’s first intentional dose of lysergic acid diethylamide (LSD).

Since then, April 19th has become an international holiday known as “Bicycle Day” or “LSD Day” among those who celebrate its significance in psychedelic history.

This guide will explore when is LSD Day around the world. We’ll also look at how different cultures and countries celebrate it and why April 19th was chosen as the international day of commemoration for Hofmann’s work.

So read on to learn more about When LSD Day is, and start celebrating its significance in psychedelic history.



LSD (Lysergic Acid Diethylamide) is a POWERFUL hallucinogenic drug that alters the brain’s perception of reality [1]. When ingested, LSD affects serotonin levels in the brain, resulting in changes to one’s mood, thoughts and behavior.

It can cause users to experience altered states of consciousness and INTENSE visual and auditory hallucinations. 

While some people may find these effects pleasurable or even therapeutic, they can also be dangerous when not taken responsibly.

As such, it is IMPORTANT to understand how LSD works on the brain before deciding if it is something you want to try.


Pro Tip: An acid trip can last anywhere from six to twelve hours, so it is important to know your limits and not take too much.


What is LSD Day?

LSD Day is an INTERNATIONAL holiday celebrated on April 19th each year. This date marks the anniversary of when Swiss chemist Albert Hofmann had his first LSD trip in 1943, making it a significant milestone in psychedelic history [2]. LSD Quote (White)


History Of LSD Day

This landmark event marked a turning point in HISTORY and sparked an entire movement around psychedelic exploration and research.

At the time of his initial experiment, Hofmann was working on synthesizing various compounds at Sandoz Laboratories in Basel, Switzerland.

When he ACCIDENTALLY exposed himself to LSD in 1938, he experienced some strange effects, including an uninterrupted stream of fantastic pictures that prompted him to take a larger dose five years later. 

This act would become known as “Bicycle Day” or “LSD Day.”

This day has since been commemorated by the psychedelic community as an international holiday celebrated each year on April 19th. 

Today, people come together to HONOR Albert Hofmann’s work and explore its implications for medicine, science and psychology.


Why Is It Called Bicycle Day?

The name “Bicycle Day” comes from the story of Albert Hofmann’s famous LSD trip [3].

After ingesting the drug, he experienced an INTENSE mental and physical reaction that caused him to ride his bicycle home in a daze.

As his journey progressed, the drug’s effects intensified, and he eventually had to be assisted off his bicycle as his condition began to assume threatening forms.

When he finally arrived home, Hofmann realized that he had been under the influence of LSD—the FIRST intentional trip in history.


Pro Tip: Cars were restricted during World War II, so Hofmann had no choice but to make his way home on a bicycle.


He later wrote a memoir ‘LSD: My Problem Child’ where you can read more about his journey, giving amazing descriptions and experiences during his first LSD trip.

“Kaleidoscopic, fantastic images burst in upon me, alternating, variegated, opening and then closing themselves in circles and spirals, exploding in coloured fountains, rearranging and hybridizing themselves in constant flux,” – its a great extract which shows the intensity of his experience.

Bicycle day WASN’T recognized as a holiday until 1989. This was when Thomas B. Roberts, an American Professor of Educational Psychology (at Northern Illinois University), proposed the term to honor Albert Hofmann’s journey [4].


How Has LSD Evolved?

Since its discovery, LSD has become increasingly popular among scientific circles and is now used to treat various MENTAL HEALTH conditions.

In the 1950s, research into the drug’s therapeutic potential began to INCREASE, with many scientists exploring how it could be used to help patients suffering from various psychological issues.

As more studies were conducted over time, it became evident that LSD had powerful effects on individuals’ mental states and could be used as an adjunct therapy for TREATING depression, anxiety and other mood disorders.

This led to a surge in interest in using psychedelics for MEDICAL purposes during this period.

Today, there is still much debate about whether or not LSD should be made available as a prescription medication due to its potential RISKS and side effects.

However, recent clinical trials have demonstrated POSITIVE results when it comes to using psychedelic drugs for therapeutic purposes—which may lead us closer to discovering new treatments for mental health conditions in the future.


Celebrations Around The World

Every April 19th, people worldwide come together to celebrate LSD Day. 

From the United States and Canada to Europe, Asia, South America and beyond, psychedelic art installations, live music performances and other creative activities bring the community TOGETHER in celebration.

There is also an ONLINE presence for world Bicycle Day. Social media platforms are filled with artwork, stories and personal accounts of psychedelic exploration on April 19th. 

People even choose to take doses of LSD on this day to show respect for Hofmann’s work.


Potential Reflection On Substance Use

While Bicycle Day is celebrated as a time of exploration and honoring Albert Hofmann’s work, it is also important to consider the potential risks associated with consuming drugs like LSD.

When using psychedelics or any other psychoactive substance, it is essential to make conscious decisions about use to MINIMIZE potential harm.

This includes being aware of one’s mental state BEFORE taking a dose, setting intentions for the experience and ensuring that there will be someone present who can provide support if needed.

Furthermore, individuals should research the drug beforehand and UNDERSTAND its effects on both mind and body before deciding whether or not to use it.

By making informed choices when consuming drugs such as LSD, we can ensure an enjoyable experience while minimizing the risk of harm.


How To Celebrate LSD Day Safely?

If you are interested in celebrating Bicycle Day, there are a few ways to do so safely.

  1. Connect with the psychedelic community: Talk to others who have taken LSD or other psychedelics before and share their experiences.
  2. Create art: Make some new artwork using colors, shapes and symbols that honor Hofmann’s legacy.
  3. Listen to music: Take a listening journey through different genres of music and explore how LSD has inspired artists over the years.
  4. Research more about Albert Hofmann’s life and work: Learn more about why he created LSD and what his vision was for its use in medicine and research
  5. Have a discussion group: Gather with friends or strangers online/in-person (if regulations allow) to discuss ideas related to psychedelics, and mental health awareness.
  6. Plan an adventure outdoors: Go on a hike, take pictures of nature or explore your local area while abiding by social distancing guidelines if necessary
  7. Visit a sacred site near you (or virtually): Seek out sites like temples, churches or meditation spots that may offer spiritual guidance as part of this day’s celebration
  8. Attend an event (online/offline): Find nearby events where you can safely celebrate with fellow psychedelic enthusiasts honoring Albert Hoffmann’s contribution to the psychedelic movement.
  1. Reflect on your own experiences with psychedelics: Take time to consider what roles psychedelics have played in your life, both personally and culturally. 
  2. Donate or raise money for research: When used responsibly under responsible supervision, psychedelics can lead us closer to discovering new treatments for mental health conditions in the future. Consider donating to organizations that are working towards advancing this research, or use the day to fundraise for a psychedelic cause close to your heart.



LSD Day is a special occasion that allows us to reflect on the incredible work of Albert Hofmann and celebrate his contributions to psychedelic science.

When celebrated responsibly, this day can be an opportunity for psychedelics enthusiasts to come together and commemorate this important historical figure.

By connecting with the psychedelic community, engaging in creative activities, or exploring sacred sites, we can honour the legacy of Hofmann while also increasing our understanding of psychedelics and their potential therapeutic benefits.



  1. on I. Hallucinogens DrugFacts | National Institute on Drug Abuse. National Institute on Drug Abuse. Published April 22, 2019. Accessed January 14, 2023.
  2. High Times. Science History Institute. Published February 2, 2017. Accessed January 14, 2023.
  3. DeAngelo A. Bicycle Day: Honoring The Onset Of The Psychedelic Revolution As It Zooms Across The Globe. Forbes. Published April 18, 2022. Accessed January 14, 2023.
  4. McMillan T, McMillan T. Bicycle Day – Catalyst Magazine. Catalyst Magazine. Published March 30, 2013. Accessed January 14, 2023.
  5. Can LSD and other psychedelics be used as medicine or therapy? (n.d.). Drug Policy Alliance. Available at:

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