Psilocybin

What is psilocybin?

Psilocybin occurs in certain mushrooms. The body converts it to psilocin, which produces the psychedelic effects. It is a classic psychedelic, in the same broad group as LSD.

Psilocybin is being studied as part of supported treatment for several mental-health conditions. These studies involve screening, a known substance and supervision. Those conditions matter when interpreting the findings.

Holze et al. (2022): controlled comparison of psilocybin and LSD · Hinkle et al. (2024): systematic review of adverse events

What might it feel like?

Just before the journey, you might feel both excited and anxious. As the experience begins, colour and sound may become more vivid. You may notice a warm glow, a steady stream of thoughts, or laughter starting to emerge. You may also feel queasy or restless and want to get comfortable and lie down.

Becoming immersed

As the music plays, you may notice yourself drifting into and out of a dream, absorbed in thoughts, images and music for longer periods of time. Expanding and contracting shapes and patterns may seem to become the music, and the music become the visuals.

Your usual sense of your body, time and space may recede. Journeyers describe a deeply embodied unity with others and the world, sometimes accompanied by a profound recognition of its beauty. There may be tremendous joy, love or a sense of belonging that is difficult to put into words.

Visions and memories of people, places and key life experiences may come up. Pleasant and unpleasant emotions can emerge close together. You might cry, laugh, feel grief or tenderness, or find a new perspective on something you have been carrying. Some experiences feel spiritual; others feel personal, physical or simply unfamiliar.

In someone’s own words

“My mind was still blown by amazement by how all this is even possible”

Erowid writer bongd81, quoted in Brouwer et al. (2025)

This writer describes returning to a garden as the experience eased, listening to music and feeling grateful to be back in familiar surroundings.

If you feel overwhelmed, tell your sitter. A familiar voice, quieter music or feeling your feet on the floor may help you settle. You can ask for reassurance or a change in the surroundings.

When might effects begin?

Effects often begin within the first hour, though they may take longer. In a controlled study using psilocybin capsules, the average onset was around 50 minutes and varied considerably between participants. Mushroom preparations may differ. Avoid taking more because the effects seem slow to begin.

Holze et al. (2022): controlled comparison of psilocybin and LSD

Does it follow a predictable arc?

Effects generally build, become more intense and gradually ease. That does not always feel like a smooth curve. Periods of relative calm can be followed by stronger sensations. There is no precise moment when you should expect an insight or a turning point.

How long might it last?

In a controlled comparison, psilocybin’s effects lasted about six hours on average, with some participants reporting substantially shorter or longer experiences. Leave room for rest and support afterward. Avoid driving or other responsibilities while you remain affected or sleep-deprived.

Holze et al. (2022): controlled comparison of psilocybin and LSD · Evens et al. (2023): systematic review of the psychedelic afterglow

Coming down and the days afterward

As the intensity eases, you may move between deep absorption and a more familiar sense of yourself. There can be laughter, tears, peace or relief. Movement may feel free and easy as it ebbs and flows with the music. You might want to stretch gently, eat, rest or spend quiet time with someone you trust.

You may also feel tired or unsettled. Leave space for how you actually feel, and take your time putting the experience into words.

Some people describe an afterglow. It is not universal, a guaranteed recovery period or a fixed window in which you must change your life. If anxiety, low mood, unusual perceptions or sleep problems persist, worsen or interfere with daily life, seek professional support.

Qualitative study (2025): mushroom come-up and come-down reports · Evens et al. (2023): systematic review of the psychedelic afterglow

Read Integration for ways to reflect without rushing to a conclusion.

Write down what feels meaningful if you want to, and give yourself time before making major decisions. If a memory emerges, explore it gently without pressure from anyone to decide exactly what happened.

Potency: why there is no universal amount

The weight of a mushroom is not a reliable measure of the psilocybin it contains. Potency varies between species, batches and individual mushrooms. A quantity used in a study with purified psilocybin cannot be reliably converted into grams of dried mushrooms.

A stronger experience is not necessarily more useful, and a previous experience does not reliably predict the next one. Never take more to overcome suspected medication-related blunting.

Chemical analysis of Psilocybe mushrooms (2022) · Holze et al. (2022): direct comparison of LSD and psilocybin

Mushrooms and other products

Chemical analysis shows that mushroom species and even parts of the same mushroom can contain different amounts of active compounds. The weight or appearance of a product gives limited information about its strength.

Changing the preparation can also change the timing or intensity. Claims that lemon juice reliably controls the experience or prevents nausea have little clinical research behind them. Drug checking provides information within the limits of the test used.

Chemical analysis of Psilocybe mushrooms (2022)

Medications and psilocybin

Small monitored studies of psilocybin with an SSRI have not detected an increased serotonin-toxicity signal. In a short escitalopram trial, positive effects were largely preserved; an uncontrolled study of 19 people with depression who continued an SSRI reported improvement. Neither establishes safety for every person or proves that continuing and stopping work equally well. Becker et al., 2022 — psilocybin and escitalopram trial, Goodwin et al., 2023 — psilocybin with a continuing SSRI.

Do not abruptly stop an SSRI or another psychiatric medication to prepare for a psychedelic experience. Taking an antidepressant does not automatically mean you need to taper. Continuing, changing or tapering a medication is an individual decision with the prescribing clinician, taking into account the particular medication, psychedelic and your current health. Never increase a psychedelic dose to overcome suspected medication-related blunting. Read Medication considerations for the substance-specific evidence and questions to bring to your prescriber.

Risks and when to get help

Nausea, headache, anxiety and changes in blood pressure can occur. Confusion or impaired judgement can create danger even when physical symptoms seem mild. Some people experience prolonged distress or recurring visual disturbances. Selected clinical studies cannot establish safety for everyone.

Bipolar disorder, psychosis vulnerability, unstable mental health and important cardiovascular conditions need particular caution. Lithium raises a serious concern about seizures with classic psychedelics; do not stop lithium to make room for a psychedelic. Review this and other combinations in Medication considerations.

Call emergency services for seizures, collapse, breathing difficulty, chest pain, severe overheating, or confusion with marked stiffness or repeated jerking. Do not assume concerning symptoms are simply part of the experience.

Hinkle et al. (2024): systematic review of adverse events · Johnson et al. (2008): human psychedelic research safety guidelines

Yerubandi et al. (2024): acute adverse effects of therapeutic psilocybin

Nayak et al. (2021): lithium and seizure reports. These self-reports raise concern about the combination; the study cannot establish the frequency of seizures.

Medsafe: symptoms of serotonin toxicity.

How do psychedelics work?

When psilocybin is ingested, it is converted to psilocin. Activation of serotonin 5-HT2A receptors is central to its acute psychedelic effects, although psilocin acts at other receptors too. Human receptor-occupancy findings support this role; they do not establish why a particular person improves. Madsen et al. (2019).

Psilocybin changes patterns of activity within and between brain networks. Changes involving the default mode network may accompany altered self-experience, but it does not switch off. Some more selective changes can persist afterward; their meaning is still being studied. This is not evidence of a brain reset or guaranteed clinical benefit. Siegel et al. (2024).

Read Basic Psychedelic Neuroscience for the findings, leading models and uncertainties.

What does this mean for me?

Before deciding, work through the medical-screening questions. Use these questions to identify what needs further discussion with a qualified clinician. Bipolar disorder, a personal or family vulnerability to psychosis, significant suicidality, unstable mental health, important medical conditions or complex medication use need appropriate professional assessment.

Think about why you want this experience, how steady life feels right now, and who could help during and afterward. Consider what you hope to gain and whether the possible benefits are worth the risks for you. Waiting, choosing another form of support or deciding against it are valid choices.

Use the Preparation Guidebook to make a plan, the Sitter Guidebook to agree on support and boundaries, and the Integration Guidebook to reflect afterward. Take time afterward to consider what was useful and how you are feeling.

Johnson et al. (2008): human psychedelic research safety guidelines

Sources and limits

These pages bring Entheo’s descriptions of lived experience together with first-person accounts, qualitative interviews and clinical research. Qualitative studies help us understand how people experience and make meaning of these states. Clinical studies help address different questions, including medication interactions and physical risks.