Psilocybin: Facts about the main ingredient in psychedelic 'magic' mushrooms

magic mushrooms are chemicals called psilocybin and psilocin
(Image credit: Getty Images)

Psilocybin is the main psychoactive ingredient in hallucinogenic mushrooms, also called "magic mushrooms" or "shrooms." There are over 100 species of mushrooms that contain psilocybin. 

Although people have been consuming magic mushrooms for thousands of years, the compound wasn't isolated until 1957 and it was produced synthetically a year later. Since 1970, psilocybin and psilocin (a closely related compound) have been listed by the U.S. Drug Enforcement Association (DEA) as Schedule I substances — the federal government's most restrictive category.

Despite these restrictions, recent clinical trials have found psilocybin to be a promising therapy for treatment-resistant anxiety and depression. Because of this, the U.S. Food and Drug Administration (FDA) has designated psilocybin as a "breakthrough therapy"— an action meant to accelerate the drug development and review process. 

In February 2023, Australia’s Therapeutic Goods Administration announced that psychiatrists would be able to prescribe psilocybin for treatment-resistant depression. However, the drug will only be allowed to be used in a very limited way and remains otherwise prohibited in the country.

Where does psilocybin come from?

There are over 100 species of psilocybin-containing mushrooms with varying potencies, said Matthew Johnson, an associate professor of psychiatry and behavioral sciences at Johns Hopkins School of Medicine in Baltimore who studies psychedelic drugs such as psilocybin. 

Psilocybin mushrooms have long, slender stems topped by caps with dark brown edges, according to the DEA. In the U.S., magic mushrooms are found in the Southeast and Pacific Northwest often growing in pastures on cow dung, Johnson told Live Science. They also grow in Mexico, Central and South America. The most potent species in the world is considered Psilocybe azurescens, which is found mainly in the U.S. Pacific Northwest. 

Matthew Johnson
Matthew Johnson

Matthew Johnson is an associate professor of psychiatry and behavioral sciences. One of the world’s most published scientists on the human effects of psychedelics, he has conducted seminal research in the behavioral economics of drug use, addiction and risk behavior. Johnson earned his PhD in experimental psychology at the University of Vermont in 2004 and has been working with psychedelics ever since. He is principal investigator on funded studies investigating psilocybin in the treatment of opioid dependence and PTSD.

In the early 1950s, an American banker and mushroom enthusiast named R. Gordon Wasson came across an indigenous tribe using psychoactive mushrooms when he was on vacation in Mexico, according to Drug Policy Alliance. Wasson sent samples of the mushrooms to Albert Hoffmann, a Swiss chemist known for discovering LSD. Hoffmann isolated psilocybin from the mushroom Psilocybe mexicana in 1957, and he developed a way to produce a synthetic version of the psychedelic compound a year later. 

Since 1970, psilocybin and psilocin have been listed by the DEA as Schedule I substances, the federal government's most restrictive category. Drugs in this category are believed to have a "high potential for abuse" as well as "no accepted medical use," according to the DEA. 

What does psilocybin do to the brain?

Psilocybin along with other drugs, such as lysergic acid diethylamide (LSD) and mescaline, are considered "classic psychedelics" because they can induce changes in mood, thought and perception by mimicking neurotransmitters in your brain

Once it enters the body, psilocybin is broken down into psilocin, a substance that acts like the neurotransmitter serotonin, which regulates mood. Psilocybin is known to activate a specific type of serotonin receptor in the brain that triggers its psychedelic effects, Johnson said.

Its hallucinatory effects can cause a person to see images, hear sounds and feel sensations that seem real but aren't, according to Partnership for Drug-Free Kids. Someone on psilocybin may experience synesthesia, or the mixture of two senses, such as feeling like they can smell colors. 

Related: 'Trippy' bacteria engineered to brew 'magic mushroom' hallucinogen

psilocybin growing in a forest

(Image credit: Getty Images)

Besides sensory enhancement and visual hallucinations, participants in psilocybin-assisted therapy sessions have described the drug's effects as a life-changing experience where they gain deep insight that shifts the way they think about themselves. 

A mystical type of experience has also been linked with the use of psilocybin, Johnson said. People have described feeling at one with humanity, feeling a sense of unity, and feeling a sense of self dissolve after consuming the psychedelic compound, he explained. 

Studies have shown that after taking psilocybin, there is a sharp increase in communication between areas of the brain that normally don't talk to each other, which may partly explain the new insights people experience. There's also a quieting of deeply entrenched thought patterns that contribute to addictions, anxiety and depression, Johnson said. 

Is psilocybin legal?

The FDA has granted some scientists permission to use psilocybin in research but the recreational use of psilocybin is illegal in the U.S. However, its illicit use has been decriminalized in two cities (Denver and Oakland, California) and other cities are working on similar measures, Johnson said. 

In February 2023, Australia was the first country to legalize the use of psilocybin for medical use. The Therapeutic Goods Administration announced that psychiatrists would be able to prescribe the substance from July 2023 for depression. However, possession and recreational use of the drug remains criminalized. 

People have been ingesting psilocybin-containing mushrooms for thousands of years as part of religious ceremonies or for healing purposes. 

Magic mushrooms can be made into a tea, eaten raw or dried, ground into a powder and put in capsules, or coated in chocolate, to mask their bitter flavor and disguise them as candy, Johnson said. The hallucinogenic effects may begin within 20 to 40 minutes of use and last about 3 to 6 hours, according to the U.S. Department of Justice

A cluster of Psilocybin Mushrooms

(Image credit: Getty/ Yarygin)

Studies on the possible medical benefits of psilocybin and other psychedelics began in the 1950s and '60s, immediately after Hoffmann created a way to produce the chemical synthetically. 

Although findings showed promise for treating anxiety, depression and addiction, research in the U.S. came to a halt in 1970, when President Richard Nixon signed the Controlled Substances Act. This law was viewed as a political response to a growing fear of psychedelic drug use in young people and the spread of the counterculture movement. 

Three decades later, Roland Griffiths, a psychopharmacologist at Johns Hopkins, won FDA approval to study psilocybin, ushering in a new era of psychedelics research with more rigorous scientific standards than earlier studies. 

When used in current research sessions, participants take a pill containing a high dose of synthetic psilocybin with professionals monitoring them and providing psychological support, Johnson said. They typically receive counseling before and after the psychedelic experience.

Psilocybin therapy research

Psilocybin has shown promise for treating a variety of difficult-to-treat health conditions. 

For example, the results are extremely positive for the use of psilocybin in the treatment of smoking cessation and depression, Johnson said. Clinical trials have reported that just one to three doses of psilocybin given in conjunction with cognitive behavioral therapy have helped patients quit their smoking habit, he said. Afterward, people feel more confident in their ability to change behavior and manage their addictions. 

Results are also promising for the use of psilocybin in reducing cancer-related anxiety and treatment-resistant depression — two areas where there is a huge need for better treatment options, Johnson said. 

Results from the largest-ever trial of the therapy were published in 2022, with researchers preparing to launch an even larger trial, called Phase 3, which will supply the needed data for FDA approval.

Psilocybin along with supportive therapy appears to help people come to grips with problems and learn from these experiences, Johnson said. The treatment may induce insights and novel perspectives that promote mental flexibility and may cause lasting behavior changes six months to a year later. 

Small studies of psilocybin have also suggested benefits as a treatment for alcohol addiction and obsessive-compulsive disorder

Potential risks of psilocybin

The most common negative side effect of psilocybin is the potential for a "bad trip," Johnson said. High doses of psilocybin can cause overwhelming feelings of anxiety, fear and confusion that can lead to dangerous behavior if not used under medical supervision.  

Psychedelics are very intoxicating substances, and their side effects can be challenging to manage even in the relatively safe framework of a research setting, Johnson said. Researchers reduce these risks by prohibiting people with a history of psychosis from participating in psilocybin studies. Psilocybin can also moderately increase blood pressure, which is why people with heart problems are excluded from studies, he added. Other possible side effects of psilocybin use include nausea, vomiting, headaches and stomach cramps. 

For recreational users, misidentification of mushroom species is one of the biggest concerns. Some poisonous varieties of mushrooms in the wild bear a strong resemblance to psilocybin species, according to ProjectKnow. Inexperienced mushroom hunters might not recognize the difference, and could accidentally ingest a poisonous mushroom, which could lead to liver failure or death.  

Historical uses of psilocybin

Central Americans were using psilocybin mushrooms before Europeans landed on the New World's shores, according to Science Direct; the fantastical fungi grow well in subtropical and tropical environments. But how far back were humans tripping on magic mushrooms?

It's not an easy question to answer, but a 1992 paper in the short-lived journal, "Integration: Journal of Mind-Moving Plants and Culture," argued that rock art in the Sahara dating back 9,000 years depicts hallucinogenic mushrooms. The art in question shows masked figures holding mushroom-like  objects. 

Other drawings show mushrooms positioned behind anthropomorphic figures — possibly a nod to the fact that mushrooms grow in dung. The mushroom figures have also been interpreted as flowers, arrows or other plant matter, however, so it remains an open question whether the people who lived in the ancient Sahara used 'shrooms.

According to Sierra College anthropologist John Rush, magic mushrooms explain why kids wait for a flying elf to bring them presents on Dec. 25.

Rush said that Siberian shamans used to bring gifts of hallucinogenic mushrooms to households each winter. Reindeer were the "spirit animals" of these shaman, and ingesting mushrooms might just convince a hallucinating tribe member that those animals could fly, according to Psychedelic Spotlight

Plus Santa's red-and-white suit looks suspiciously like the colors of the mushroom species Amanita muscaria, which grows under evergreen trees. However, this species is toxic to people. Feeling like you've just taken a bad trip? Not to worry. Not all anthropologists are sold on the hallucinogen-Christmas connection. But still, as Carl Ruck, a classicist at Boston University, told Live Science: "At first glance, one thinks it's ridiculous, but it's not."

Additional resources

This article is for informational purposes only and is not meant to provide medical advice. 

Live Science Contributor

Cari Nierenberg has been writing about health and wellness topics for online news outlets and print publications for more than two decades. Her work has been published by Live Science, The Washington Post, WebMD, Scientific American, among others. She has a Bachelor of Science degree in nutrition from Cornell University and a Master of Science degree in Nutrition and Communication from Boston University.

  • Truthseeker007
    I tried them once in High School. And it was a great experience. It just seemed to really open my consciousness onto other levels and I felt very happy. I have never come across them again but I would take them if offered to me.

    Only in this crazy world that we live in do they make natural plants illegal. It should be illegal to make natural plants illegal. We should all have the freedom to use the natural things this Earth gives and not be constricted from a government.
    Reply
  • Mr. Plant
    Truthseeker007 said:
    I tried them once in High School. And it was a great experience. It just seemed to really open my consciousness onto other levels and I felt very happy. I have never come across them again but I would take them if offered to me.

    Only in this crazy world that we live in do they make natural plants illegal. It should be illegal to make natural plants illegal. We should all have the freedom to use the natural things this Earth gives and not be constricted from a government.
    I agree with you man, I'm not sure why they are illegal- maybe they are poisonous? I'm dealing with a lot of anxiety in general, and I could really use a dose of this thing. I'm not sure why the FDA is taking so long to research and develop it as prescription meds. I mean, there's a lot of evidence I feel that it can reset one's default mode network, and that is really appealing to someone who has a lot of anxiety and panic. It makes sense to use it, because yes, it is a plant, and plants are from nature. If it has such power to even reduce anxiety in cancer patients, why can't a prototype be used to cure depression and obsessive compulsive disorder? I'm interested in participating in trials regarding psilocybin, but I can't seem to find one that doesn't require me to be tracked for at least 3 months. If this plant, which has been around for thousands of years, has the power to fundamentally change you, and it doesn't have any life-threatening side-effects, why not?
    Reply
  • Truthseeker007
    Mr. Plant said:
    I agree with you man, I'm not sure why they are illegal- maybe they are poisonous? I'm dealing with a lot of anxiety in general, and I could really use a dose of this thing. I'm not sure why the FDA is taking so long to research and develop it as prescription meds. I mean, there's a lot of evidence I feel that it can reset one's default mode network, and that is really appealing to someone who has a lot of anxiety and panic. It makes sense to use it, because yes, it is a plant, and plants are from nature. If it has such power to even reduce anxiety in cancer patients, why can't a prototype be used to cure depression and obsessive compulsive disorder? I'm interested in participating in trials regarding psilocybin, but I can't seem to find one that doesn't require me to be tracked for at least 3 months. If this plant, which has been around for thousands of years, has the power to fundamentally change you, and it doesn't have any life-threatening side-effects, why not?

    So true. I think the problem is that they don't really care about fixing problems and helping people get better. It is about control and how much money can they make off of it. If they can't find a way to make money off of it then they won't do it. And the "drug war" on plants has gotten out of control. If we did truly live in a free society we would be able to put any plants into our body we want as long as we aren't harming others.

    If you take that plant and do harm others then yea I can see a problem with that. We are headed in the right direction though with legalization of marijuana in a few states. We still have more to go though with the prohibition. And they should have learned with Alcohol that prohibition doesn't work. But like I said it is all about control, power and money. They don't care about people getting better. They would rather give you OxyContin or Zoloft so you can go insane and shoot a bunch of people.
    Reply
  • MichaelM
    I really believe in ten years they will be commonly used to treat certain ailments (PTSD, Depression etc..) pharmaceuticals are used to treat now. Not exclusively, but definitely used / prescribed.
    Reply
  • sarajo
    I dont think I'll be using it
    Reply