Psilocybin is often described as having low physical toxicity, but that does not mean it has no effect on the body. One of the most important questions is how psilocybin and the heart interact. This harm reduction guide explains the short-term effects on heart rate and blood pressure, the debated long-term concern about heart valves with frequent microdosing, and who should be especially careful.
This article is for general information only. It is not medical advice. If you have a heart condition or take heart medication, talk to a doctor before considering any psychoactive substance.
Short-Term Effects of Psilocybin on the Heart
During a psilocybin experience, heart rate and blood pressure usually rise moderately. In a 2022 study at University Hospital Basel that compared psilocybin with LSD in healthy volunteers, psilocybin raised blood pressure more than LSD, while LSD raised heart rate more [1]. Overall, both substances had comparable stimulating effects on the cardiovascular system.
In healthy people, these changes are usually modest and short-lived. In clinical trials, participants are screened carefully, and staff monitor blood pressure during sessions. However, the same changes may matter more for people with existing heart problems.
Psilocybin and the Heart Valves: The 5-HT2B Question
A different concern involves long-term, frequent use. Some medicines that strongly activate a serotonin receptor called 5-HT2B have been linked to heart valve damage. The best-known example is fenfluramine, a weight-loss drug that was withdrawn in the late 1990s after reports of heart valve disease. Research on this case pointed to 5-HT2B receptors as a likely cause [2].
Psilocin, the active form of psilocybin, can also act on 5-HT2B receptors. For a single dose or occasional use, this is not thought to be a major issue. However, microdosing involves taking small amounts regularly over weeks or months. A 2023 review examined this risk for psilocybin, LSD and other substances [3]. It found that the substances could act on the 5-HT2B receptor, and that safety margins at typical microdoses were larger than for known problem drugs, but not without potential risk. Importantly, no studies have yet been designed to properly test this risk in people.
In short, the risk of valve damage from microdosing is uncertain, not proven. It is one reason why many people take regular breaks. Read our guide to microdosing magic mushrooms for more on schedules and breaks.
Who Should Be Especially Careful?
Clinical trials usually exclude people with:
- uncontrolled high blood pressure
- heart disease, heart rhythm problems or a history of heart attack or stroke
- known heart valve disease
- certain medications that affect heart rate, blood pressure or serotonin
People in these groups face higher risks from psilocybin and the heart effects described above. Therefore, they should seek medical advice before considering any psychedelic.
Other Physical Effects to Know About
Besides the heart, psilocybin can cause nausea, headaches, dizziness and dilated pupils. These effects usually pass within hours. In addition, psychological effects such as anxiety can themselves raise heart rate. Our guides to psilocybin effects and safety and handling a bad trip explain these effects further.
Emergency Signs
Call emergency services, 112 in Europe, if someone who has taken psilocybin has:
- chest pain or pressure
- severe shortness of breath
- fainting or a very irregular heartbeat
- signs of a stroke, such as sudden weakness, facial drooping or trouble speaking
Frequently Asked Questions
Is psilocybin bad for your heart?
For most healthy people, occasional use causes only a temporary, moderate rise in heart rate and blood pressure. However, people with heart conditions face higher risks, and the long-term effects of frequent microdosing are not well understood.
Does microdosing damage heart valves?
There is no proof that it does, but a theoretical risk exists because of the 5-HT2B receptor. Researchers have called for proper studies.
Can I take psilocybin with blood pressure medication?
Speak to a doctor first. Interactions depend on the specific medication and your health.
Conclusion: Psilocybin and the Heart
Psilocybin and the heart interact in two main ways: a short-term rise in heart rate and blood pressure, and a possible, unproven long-term risk to heart valves with frequent use. For most healthy people, occasional use is low risk for the heart, but people with heart conditions should be cautious and seek medical advice. As always, accurate information and careful choices are the best protection. Learn more in our magic mushroom dosage guide.
Sources
- Holze F, et al. Direct comparison of the acute effects of lysergic acid diethylamide and psilocybin in a double-blind placebo-controlled study in healthy subjects. Neuropsychopharmacology. 2022. doi:10.1038/s41386-022-01297-2
- Rothman RB, et al. Evidence for possible involvement of 5-HT2B receptors in the cardiac valvulopathy associated with fenfluramine and other serotonergic medications. Circulation. 2000. doi:10.1161/01.CIR.102.23.2836
- Tagen M, et al. The risk of chronic psychedelic and MDMA microdosing for valvular heart disease. Journal of Psychopharmacology. 2023. doi:10.1177/02698811231190865
