Understanding psilocybin: what we know

Psilocybin is one of the best-known natural compounds in the psychedelic family. It's also one of the most talked about, and not everything said about it holds up. Here is a calm overview: what it is, how it acts in the body, what research is looking at, and where the open questions lie.

In short: psilocybin is a natural compound found in certain mushrooms and in psilocybin truffles. The body converts it into psilocin, which acts mainly on the brain's 5-HT2A serotonin receptors. What it does depends heavily on the dose, the person and the context, and research on microdosing in particular is still preliminary.

What is psilocybin?

Psilocybin is a compound produced naturally by a few hundred species of fungi, most of them from the genus Psilocybe. It is found in mushrooms, and also in truffles (sclerotia): the compact, underground structures that some species, such as Psilocybe mexicana, form.

Humans have known these fungi for a very long time. In Mesoamerica in particular, they have a documented place in ceremonial and spiritual traditions that are centuries older than modern science.

Truffles and mushrooms: the same compound

Psilocybin truffles and psilocybin mushrooms contain the same active compounds. The difference is mainly botanical: the mushroom is the fruiting body that grows above ground, while the truffle, or sclerotium, is a dense structure that forms below the surface. We compare the two in magic truffles vs mushrooms.

In both cases, the amount of psilocybin varies naturally from one species, batch or piece to another. That variation is one reason why a measured portion is easier to approach calmly than guesswork. For quantities, see how much is a microdose.

How it acts in the body

Psilocybin itself is what chemists call a prodrug. Once ingested, the body converts it into psilocin, the molecule that actually acts on the brain.

Psilocin has a structure close to serotonin, one of the brain's chemical messengers. It binds mainly to a receptor called 5-HT2A, which is involved in perception and in the way the brain processes information. This is the main pathway researchers study to explain psilocybin's effects. The full picture, however, is far from complete.

The dose changes everything

What psilocybin does depends heavily on the amount taken, on the person, and on context: what is often called set and setting, meaning state of mind and surroundings.

• At high doses, psilocybin can profoundly alter perception, the sense of time and the sense of self. These experiences can be intense, sometimes difficult, and they are not what this site is about.
• At very low doses, what is called microdosing, the aim is precisely to stay below the threshold of noticeable effects. Most people who microdose describe something subtle, if they notice anything at all. We explain the difference between a full dose and a microdose in a separate article.

What research is exploring

Scientific interest in psilocybin has grown strongly over the past fifteen years. Two quite different fields need to be kept apart.

Clinical research at high doses

Universities and hospitals are studying psilocybin in strictly supervised medical settings: carefully screened participants, high doses given in one or a few sessions, and extensive professional support. This work is ongoing and its conclusions are still debated. It does not concern microdosing, and it says nothing about unsupervised use of products sold to the public. See also why microdosing is not therapy.

Research on microdosing

Studies on microdosing are fewer, and the data remain preliminary. Many surveys rely on self-reports, which are hard to interpret. Placebo-controlled studies published in 2021 and 2022, including a self-blinding study by Szigeti et al., found that people who had taken a placebo often reported changes similar to those who had taken a microdose. In other words, expectations play a major role, and the results are mixed.

That doesn't mean people's experiences aren't real to them. It means that, for now, science cannot say what microdosing does or doesn't do.

How to read claims about psilocybin

Psilocybin is often in the news, and headlines don't always distinguish between very different kinds of evidence. A few questions help:

• What dose was studied? Most clinical work uses high doses in a supervised setting. Its findings cannot simply be transferred to microdoses.
• Was there a placebo group? Without one, it is impossible to know how much of a reported change comes from the substance and how much from expectations.
• Who was studied? Screened volunteers, people who already microdose, or animals in a laboratory each answer a different question.
• Who is telling the story? Sellers, including us, have an interest in the subject. Independent sources such as the European Union Drugs Agency are a useful counterweight.

Placebo and expectations

What people expect to feel can shape what they notice. Knowing that you have taken something, or simply paying closer attention to your mood, can change how a day is perceived. The self-blinding design of the Szigeti et al. study was built to separate those expectations from the substance: participants prepared their own capsules and did not know which ones contained a microdose.

That doesn't make personal experiences meaningless. It means they are hard to interpret on their own. A microdosing journal that includes the days without a dose, read back after a few weeks, gives a more honest picture.

What people describe

Among those who microdose, some describe feeling a little more present, more attentive to their surroundings, or more curious. Others notice nothing in particular. These are subjective impressions that vary from one person to another and from one day to the next, not promised effects.

At BIEN, that's the spirit we suggest: observe calmly, keep notes, and don't expect miracles.

Legal status

The legal status of psilocybin varies widely around the world, and many countries classify it as a controlled substance. Before anything else, find out what applies where you live (see the box below).

Practical safety points

• Stay low. Microdosing is meant to stay below the threshold of noticeable effects. More is not better.
• Keep the day simple. Choose a calm day, and don't drive or operate machinery after taking psilocybin.
• Don't mix. Avoid alcohol and other substances; see why microdosing and alcohol don't mix.
• Know what to do if it's too much. Stay somewhere calm, with someone you trust, and seek medical help if you feel unwell. More in took too much? What to do.

The open questions

Much is still unknown: the long-term effects of repeated low doses, the role of individual sensitivity, possible interactions with medication. Honesty means saying so. If you're curious, the best attitude is a mix of curiosity and caution.

Important: psilocybin truffles are for adults (18+) only. They are not recommended during pregnancy or breastfeeding, if you or a close relative has a history of psychotic or bipolar disorders, if you have a heart condition, or if you take any medication (especially antidepressants or lithium). Do not drive after taking them and do not combine them with alcohol. Talk to your doctor first.

Psilocybin truffles are sold legally in the Netherlands, where BIEN is based. Their status varies from country to country: check the law in your own country.

FAQ

What is psilocybin?

Psilocybin is a natural compound produced by certain fungi, mostly of the genus Psilocybe, and found in both mushrooms and truffles. In the body it is converted into psilocin, the molecule that acts on the brain.

What are the effects of psilocybin on the body?

They depend above all on the dose. At microdose level, physical sensations are usually described as subtle or absent. At higher doses, people report marked changes in perception and sometimes discomfort such as nausea. Anyone with a health condition should talk to a doctor first.

How long does psilocybin take to work?

Taken by mouth, effects are generally described as starting within the first hour, and this varies from person to person. With a microdose, there is often nothing clear to notice. See how long a microdose lasts.

Do truffles and mushrooms contain the same psilocybin?

Yes, the compound is the same. What differs is the form of the fungus and the amount, which varies naturally between species, batches and pieces.

Sources

• Szigeti B. et al. (2021), "Self-blinding citizen science to explore psychedelic microdosing", eLife
• European Union Drugs Agency (EUDA): information on drugs in Europe
• PubMed: scientific literature on psilocybin microdosing
• Government of the Netherlands: drugs policy