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Encyclopedia Psychedelica: What is LSD?

The article Encyclopedia Psychedelica: What is LSD? was originally published on Microdose.

To help celebrate Bicycle Day coming up on April 19th (one…



The article Encyclopedia Psychedelica: What is LSD? was originally published on Microdose.

To help celebrate Bicycle Day coming up on April 19th (one of psychedelics’ unofficial birthdays), Microdose is devoting the month of April to an exploration of LSD. So let’s start with the big question: what is LSD? 

We take a deeper look at this famous (and infamous) compound. 


What is LSD? An introduction

The current psychedelic renaissance has led to a renewed appreciation of various psychedelic substances once deemed dangerous and therapeutically useless. Of these, Lysergic acid diethylamide (known as LSD or “acid”) is perhaps one the most popular and controversial psychedelics.


LSD History

LSD has been a subject of fascination, controversy, and mystique for decades. From its association with the counterculture movement of the 1960s, to its present-day position at the forefront of new psychedelic therapy methods, many people are curious about exactly  what LSD is, LSD’s effects, and how it might play a role in the future of mental health. 

LSD is a powerful psychedelic drug first synthesized in 1938 by Swiss chemist Albert Hofmann. It is derived from a fungus called ergot, which grows on rye and other grains. The drug, which was Hofmann’s 25th derivative of ergot, ended up being shelved and forgotten about since it performed poorly as the circular respiratory system stimulant it was supposed to. It wasn’t until five years later that Hofmann would accidentally stumble upon (and ingest) the molecule, experiencing the intense psychedelic qualities and forever changing the course of human history (a moment we celebrate on April 19th with Bicycle Day, commemorating Hoffman’s famous bicycle ride and having the world’s first documented acid trip)


Albert Hoffman and his LSD molecule


Throughout the 1950s and 1960s, LSD gained popularity among therapists and researchers for its potential to treat mental health conditions like depression, anxiety, and addiction. Hundreds of research papers were published on its potential benefits and LSD began to be accepted by the mainstream. 

Soon, however, the drug escaped the lab and became a symbol of counterculture, with famous figures like Timothy Leary advocating for its widespread use. It was a time of intense cultural upheaval and politicians and conservatives began to vilify psychedelics as a way of vilifying their cultural and political opponents. 

In 1970, this came to a head as President Nixon 1970 signed the Controlled Substances Act, placing LSD in Schedule I, in the same category as heroin. LSD was then relegated to the underground, only re-emerging into the mainstream in the last decade.


LSD Effects

LSD is a powerful compound. The effects of LSD vary from person to person, depending on factors like dosage, environment, and individual mental state (“set and setting” being crucial in dictating the quality of one’s experience)

Common LSD effects include:

  • Visual hallucinations: Users often report seeing vivid colors, geometric patterns, and distortions in their environment.
  • Altered perception of time: Time may seem to slow down or speed up, with events taking on a dream-like quality.
  • Emotional changes: Feelings of euphoria, connectedness, and heightened empathy are common, but users may also experience anxiety, paranoia, or panic.
  • Synesthesia: Some users report experiencing sensory crossover, such as “hearing” colors or “seeing” sounds.
  • Spiritual experiences: Many users describe profound, mystical experiences that can lead to lasting changes in their worldview.
  • Therapeutic healing: Anecdotal accounts, now being backed by research, show feelings of increased well-being and improvements in conditions like anxiety.


LSD Chemistry

LSD is a complex molecule, classified as an ergoline alkaloid. Its structure closely resembles that of serotonin, a neurotransmitter involved in regulating mood, appetite, and sleep. The similarity in structure allows LSD to bind to serotonin receptors in the brain, particularly the 5-HT2A receptor.

Like many traditional serotonergic psychedelics, LSD chemistry acts on the 5HT2A receptor (a subtype of the serotonin receptor), which results in the hallucinations the drug is known for. However, there are even more mysterious and quirky things about this molecule, all the way down to its pharmacological properties, that make it one of the most coveted psychedelic drugs of all time. Perhaps the most curious pharmacological feature of LSD chemistry is the way it latches onto the brain cell’s serotonin receptors. When this phenomenon occurs, the LSD molecule is locked into place because part of the serotonin receptor folds over the drug molecule, like a lid, and stays put. It is speculated by researchers that this is the reason why the LSD experience lasts so long. Similar to other tryptamines, such as psilocybin, LSD has a chemical structure that is very similar to the neurotransmitter serotonin. It is due to this structural likeness that LSD can interact with the serotonin receptors in the brain and elicit its powerful effects. Finally, it is also interesting to note that LSD can facilitate new neural connections and neuronal “crosstalk” as found in recent brain imaging studies.


How Long Does LSD Last?

LSD’s duration of action depends on factors such as dosage and individual metabolism. Generally, the effects begin within 30 minutes to an hour after ingestion, peak between 2 to 4 hours, and gradually diminish over the next 6 to 10 hours. In some cases, residual effects may be felt for up to 24 hours. Users should be aware of the time commitment required for an LSD experience and ensure they are in a safe and supportive environment.



LSD is a fascinating compound with a rich history and complex chemistry. Its effects are highly variable, ranging from profound spiritual experiences to intense visual and auditory hallucinations. While it remains illegal in many countries, recent research has revived interest in its potential therapeutic applications, suggesting that we may still have much to learn about this enigmatic substance.

Stay tuned to Microdose for more on LSD and Bicycled Day


Interested in more like this? Check out New MindMed Study Shortens Trip with “LSD-Neutralizer and Science Feature: MindMed’s LSD Trial for ADHD


Editors Note: Some passages of this text were produced using ChatGPT

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