Psilocybin Side Effects: What Wellness Seekers Need to Know 2027

Most of what people feel from psilocybin, good or bad, comes down to one thing: how much they took. A full dose and a microdose are very different experiences, and so are their side effects. That’s why this guide keeps the two apart.

Below we walk through the common short-term side effects of each, what’s specific to microdosing, the rarer and longer-term questions people ask about, the ways people manage unwanted effects, and when to stop and get medical help.

It’s general information, not medical advice. It isn’t a substitute for a conversation with a doctor or pharmacist who knows your health.

Microdose or full dose: why the difference matters

A microdose is a small amount, meant to stay below the point where the familiar effects of psilocybin show up. People usually take it in the morning and describe an ordinary day, without visuals. Our microdosing dosage chart sets out the amounts people commonly use.

A full dose is a different experience altogether. Health Canada notes that effects appear within 15 to 45 minutes and usually last four to six hours, with heightened emotions and senses along the way.

Most of the research on side effects comes from full doses given in clinical trials. Microdosing has far less data, and most of it comes from people describing their own experience. Where the evidence is thin, we’ll say so.

Common side effects of a full dose

The best-measured picture comes from clinical trials. A 2024 meta-analysis in JAMA Network Open pooled six randomized, double-blind trials of psilocybin for depression and anxiety, with 528 participants. Headache, nausea, anxiety, dizziness and raised blood pressure were all more common with psilocybin than with the comparison treatments.

In those trials, the side effects were short-lived and resolved within 48 hours.

Keep in mind that those participants had a single measured dose, careful screening beforehand and trained staff in the room. Outside that setting, the picture can be less tidy.

Physical effects

Between the trial findings and Health Canada’s page on magic mushrooms, these are the physical effects to know about:

• nausea
• headache
• dizziness
• a faster heart rate and higher blood pressure
• numbness, particularly in the face
• muscle weakness and twitching, or convulsions

Psychological effects

Health Canada lists heightened emotions and senses, and on the harder side, anxiety, panic attacks, fear or paranoia. It also notes that a “bad trip” can happen, particularly at high doses. That can be frightening, and may include paranoia, a loss of boundaries and a distorted sense of self.

Researchers at Johns Hopkins, in their 2008 safety guidelines for hallucinogen research, call this kind of acute distress the most likely risk of a full dose. It’s tied to the hours the drug is active, and ordinary awareness returns as the effects wear off. The real danger is what someone might do while frightened and disoriented, which is why the guidelines put so much weight on preparation and company.

Side effects people report when microdosing

Because a microdose sits below the threshold of a full experience, the side effects people report are smaller and quieter. They’re also harder to pin down. Most of what we know comes from surveys of people describing their own experience, not from controlled trials.

One of the more detailed surveys, published in the Harm Reduction Journal in 2019, asked 278 microdosers about the challenges they’d run into. About 18 percent described physical discomfort. Smaller groups described lower energy, trouble focusing, a dip in mood or more anxiety. The authors are careful to say these are reported outcomes, not confirmed effects.

The physical discomfort people described included:

• headaches, or more frequent migraines
• trouble sleeping
• an upset stomach or a smaller appetite
• feeling too warm or too cold
• numbness or tingling
• small changes in vision

A 2025 systematic review in Neuropharmacology gathered 31 studies of LSD and psilocybin microdosing. It found side effects were typically dose-dependent, mild and short-lived, with raised blood pressure, anxiety and some effects on thinking among the most common. It also noted that side effects were recorded inconsistently and most studies were short, so long-term risks can’t yet be judged.

The same small things come up in our own community. Some people report a faint jitteriness on dose days, a bit of restlessness in the legs, or a mild headache as the day winds down. Others describe a restless energy that tips into impatience if the day doesn’t have anywhere to put it.

Timing matters too. A dose taken late in the day can leave some people lying in bed with their mind still quietly ticking over, which is one reason morning dosing is the usual habit. These effects tend to be minor and short-lived, but they’re real.

Less common and longer-term questions

Some questions come up again and again, even though the answers are still partly open. Health Canada says plainly that no studies have yet looked at the long-term effects of repeated use. Here’s what the evidence does say, and where it stops.

Visual changes that linger (HPPD)

Hallucinogen persisting perception disorder, or HPPD, is the return of visual disturbances first experienced while on a drug: trails, flashes of colour, halos or afterimages. A 2018 review in Brain Sciences describes it as rare and poorly understood. Most reported cases followed LSD or PCP, and it’s more often diagnosed in people with a history of psychological difficulties or substance misuse.

For some people it’s brief and fades; for others it lasts much longer. The 2008 Johns Hopkins guidelines describe it as thought to be very uncommon, and less common again in research settings with careful screening and preparation. If visual changes stay with you after the effects should have worn off, mention it to a doctor.

A personal or family history of mental illness

Health Canada says people who are predisposed to or living with psychiatric conditions may face a higher risk of side effects. The 2008 Johns Hopkins guidelines exclude anyone with a personal or close family history of psychotic or bipolar disorders. Our guide to the risks of microdosing covers who should avoid psilocybin altogether.

The heart-valve question (5-HT2B)

A 2023 review in the Journal of Psychopharmacology asked whether long-term microdosing could affect heart valves, through a serotonin receptor called 5-HT2B. Psilocybin was one of four of the five compounds reviewed (all but mescaline) that act on that receptor, and no well-designed studies have tested the risk directly. The authors judged the safety margin at typical microdose levels to be wider than for known heart-valve-damaging drugs, but not without potential risk. Our risks guide explains this in full.

Tolerance

Health Canada notes that it’s possible to become tolerant to the effects with regular use. In practice, that’s part of why most microdosing routines include regular off-days rather than a daily dose. Our dosing guide covers the common schedules and the reasoning behind them.

Ways people reduce or manage unwanted effects

None of these are guarantees. They’re the habits that come up most often among people who microdose carefully, along with the safeguards researchers use for full doses.

For microdosing

• Start at the low end of the usual range, and stay there for a few dose days before changing anything.
• Take it in the morning, so any restlessness has passed by bedtime, and drink enough water through the day.
• Keep the amount the same each time and build in off-days, so you can tell whether a change comes from the dose or just the day.
• Keep a one-line note each evening: sleep, mood, headaches, anything odd.
• Don’t drive or operate machinery if you feel any impairment, and skip alcohol, cannabis and other substances on dose days.
• If something unpleasant shows up, take a break and see whether it clears. Going lower is a better next step than pushing through.

On mixing, Health Canada is clear: combining magic mushrooms with cannabis, amphetamines or alcohol raises the risk of serious side effects.

For a full dose

The 2008 Johns Hopkins guidelines rely on careful preparation, a safe and comfortable room, and at least two trusted monitors present throughout. Outside a study, the everyday version is a calm, familiar place, a clear day with nowhere to drive, and a sober person you trust who stays with you.

If the experience turns frightening, people who’ve been through it often say the same things help: remembering that it’s temporary, slowing the breath, changing the music or the room, and letting the person with you help.

Keep your care team in the loop

If you take a prescribed medicine or see a therapist, tell them about anything you’re adding. Some medicines interact with psilocybin, and our guide to psilocybin and drug interactions explains which ones.

Microdosing sits alongside the care you’re already receiving, not in place of it. Nobody should step away from a treatment that’s working for them on the strength of an article.

When to stop and get medical help

Most side effects pass on their own. Some don’t, and these are worth acting on straight away.

Call 911 or go to the nearest emergency department

Get emergency help if someone has:

• chest pain, trouble breathing, or a racing or irregular heartbeat that doesn’t settle
• a seizure, fainting or collapse
• a high temperature, heavy sweating, shivering, muscle twitching or stiffness, or severe agitation, especially if they also take an antidepressant or another medicine that affects serotonin
• confusion or paranoia that puts them at risk of hurting themselves or someone else

That third group can be a sign of serotonin syndrome, which MedlinePlus describes as potentially life-threatening.

Call a poison centre

If you’re unsure what was taken or how much, call 1-844-POISON-X (1-844-764-7669). Health Canada says the line routes you to your local poison centre from anywhere in the country. In Quebec, the Centre antipoison du Québec is at 1-800-463-5060.

If you’re in crisis

If you’re having thoughts of suicide or self-harm, call or text 9-8-8, the Suicide Crisis Helpline. It’s open around the clock, by phone or text, in English and French.

Book a visit with your doctor

Stop microdosing and see your doctor if headaches, poor sleep, low mood or anxiety keep coming back on dose days. The same goes for visual changes that linger after the effects should have faded, or anything that feels off for more than a day or two.

Our products

If you’re looking at our own capsules, Sidekick contains Golden Teacher with lion’s mane and red reishi, in two strengths. Daydream contains Golden Teacher with ashwagandha and L-theanine. Contents are listed on each product page.

Whatever you choose, the same habits apply: start low, keep notes, take breaks, and stop if something doesn’t feel right.

Frequently asked questions

Will I feel high on a microdose day?

A microdose is meant to stay below the threshold of a full dose, but people differ. If you feel clearly altered, the amount was probably more than a microdose, so stop and review it. Our dosing guide is worth a read before your next dose day.

How long does a microdose last?

People generally describe it sitting in the first part of the day, softening into the afternoon and fading by evening. Everyone’s metabolism is a little different, so the exact shape varies. Our guide to how long psilocybin lasts covers the timing in more detail.

Are side effects a sign the dose is too high?

Sometimes. People often find that restlessness, jitteriness or a dose-day headache settles when they go lower or take an extra off-day. If an effect keeps coming back even at a small amount, that’s a reason to stop and talk to a doctor, not to push on.

Is psilocybin addictive?

Health Canada says there is little evidence that people become physically or psychologically dependent on magic mushrooms. It is possible to become tolerant with regular use, and magic mushrooms remain illegal to produce, sell or possess in Canada without Health Canada authorization. Our risks guide covers the legal side.