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Heart and blood pressure: what studies measured

The question here is what happens to heart rate and blood pressure during a session, and what is known about the heart over the longer term. This card sets out what studies and reviews report, and what was not located.

Published Information current to 7 November 2026Review due by 5 February 2027

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The short answer

What happens to heart rate and blood pressure during a session with a psychedelic, and what is known about the heart over the longer term?

In clinical studies, LSD, mescaline, psilocybin, DMT, 5-MeO-DMT and MDMA each raised blood pressure, and most also heart rate, for a short time after dosing. The studies were small and short, and mostly enrolled healthy adults or selected patients, so they could not detect rare events. For people with heart disease, diagnosed high blood pressure or older age, and for repeated use and the heart valves, controlled human data were not located in the sources read. This card is not a screening tool or medical guidance.

What do studies report about heart rate and blood pressure?

Reported findings, not recommendations. This marking applies to everything in this section. The readings come from laboratory or clinic sessions with staff present and describe those conditions only.

  • LSD in healthy adults. A pooled analysis of four crossover trials gave 83 healthy adults a total of 131 single doses of LSD (25 to 200 micrograms). These amounts were given to screened volunteers in a laboratory, not a reference for anyone else. Systolic pressure passed 140 mmHg in 48% of doses and 160 in 5%, and never passed 180. Heart rate passed 100 beats per minute in 15% of doses, with a highest value of 129. In that study, no serious adverse event occurred. The authors note that older people and people with cardiovascular risk factors were not studied. Source 1, level 1
  • Three substances compared. In a randomized crossover in 32 healthy adults, mescaline, LSD and psilocybin at psychoactive-equivalent doses each raised systolic and diastolic pressure. The one significant difference between substances was a higher diastolic pressure after psilocybin than after LSD. The authors describe the rises as moderate and transient in these screened volunteers. In that study, no serious adverse event occurred. Participants were screened healthy adults, mostly with earlier psychedelic experience. Source 2, level 1
  • LSD and MDMA. In a randomized crossover in 28 healthy adults, mean peak systolic pressure was 129 mmHg on placebo, 140 after LSD (100 micrograms) and 149 after MDMA (125 milligrams, not a classic psychedelic). These amounts were given to screened volunteers in a laboratory, not a reference for anyone else. Systolic pressure passed 140 mmHg in 14 participants after LSD, 18 after MDMA and 3 after placebo. The authors report no severe adverse events. Source 3, level 1
  • Psilocybin in clinical trials. A meta-analysis of six randomized trials of psilocybin in 528 people with depression or anxiety found raised blood pressure reported more often than with comparators (risk ratio 2.29, 95% interval 1.15 to 4.53). Only two trials contributed to that estimate, and the authors urge caution in reading it. In those trials no event was classed as serious. Four of the six trials excluded people with uncontrolled or raised blood pressure at baseline. Source 4, level 1
  • Events needing medical attention. The review reports no serious adverse events among healthy participants, with serious defined, following international (ICH) criteria, as life-threatening or resulting in death, hospitalization, significant disability or incapacity, or a congenital defect, or requiring intervention to prevent one of these outcomes. In the early window after dosing, it also reports cardiac events that needed medical intervention in 3 of 628 healthy psilocybin participants and 3 of 108 healthy DMT participants, and in none of 181 given LSD. The text read does not define a cardiac event. Its table lists these events as nonserious events that required medical or psychiatric intervention. Reporting was incomplete, and only 1% to 2% of trial participants were over 65. Source 5, level 1
  • DMT and 5-MeO-DMT. In an open-label study of intravenous DMT, 10 people (3 healthy, 7 with treatment-resistant depression) had higher blood pressure and heart rate for 20 to 30 minutes. One participant with a history of reflex fainting had a serious adverse event, a symptom-free fall in pressure and pulse lasting five minutes, which the authors report had no consequences. A systematic review of three small 5-MeO-DMT trials (78 people) reports no serious adverse events in any of them. For the first vaporized trial it records vital signs at 1 and 3 hours as unaffected, for the second no safety signal in vital signs, and for the intranasal trial a transient rise in blood pressure and heart rate that resolved within 90 minutes. The review’s own tables are not fully consistent on which formulation showed the rise. Sources 6 and 7, level 1

What is not known?

“Not located” means that the searches Metanoia ran on 7 November 2026 did not return it. For this card they covered PubMed. ClinicalTrials.gov, Embase and Google Scholar were not searched. Two recent reviews of cardiovascular safety (Nature Cardiovascular Research 2025 and European Journal of Clinical Pharmacology 2026) have no open copy and were not read, so this card does not draw on them. A 2026 study of repeated LSD doses with heart ultrasound was seen in abstract only. More searching could change the picture.

  • Heart valves and repeated use. Drugs withdrawn from sale for valve disease acted on the 5-HT2B receptor, and a narrative review notes that LSD and psilocin bind to it strongly. That review found no controlled study of valve disease in people who microdose repeatedly (source 8). In mice given very low doses of LSD for eight weeks, ventricle and valve were unchanged, and the authors say this cannot show that human microdosing is safe (source 9). In a US cross-sectional study of 286,842 adults, valve disease was recorded for 3.6% of the 37,919 people who had ever used a hallucinogen and 4.7% of the 248,923 who had not. The users were younger and had fewer heart risk factors. After the study took age and those factors into account, the users had slightly higher odds of valve disease (8% higher, odds ratio 1.08). The authors call this a hypothesis, and it cannot show that any substance caused it. It grouped LSD, mushrooms, MDMA, ketamine and PCP together and did not measure frequency (source 10). A controlled human study of valve effects was not located in the sources read.
  • People with heart disease, diagnosed high blood pressure or older age. The healthy-adult studies excluded people with physical illness, including an abnormal ECG (sources 2 and 3), and the pooled LSD analysis says older people and people with cardiovascular risk factors were not studied (source 1). Measurements in these groups were not located in the sources read.
  • Rare events and long follow-up. The pooled LSD analysis says its sample was too small to detect events occurring in 0.1% to 1% of people (source 1). The studies described measured sessions and short follow-up.
  • Ayahuasca. No primary study of its heart effects was read in full.
  • Ibogaine. It is not a classic psychedelic and is outside this card. Its cardiac findings belong to the entry on other substances, not yet written.

What this card does not say

  • It does not say who should take part, which readings matter, or what any reading means for a person. It is not a screening tool and not a standard of care.
  • Screening has its own card, about what programs ask and why. Getting medical help is a separate entry, not yet written. Nothing here concerns starting, continuing or stopping any medicine.
  • This is not an emergency resource. In the United States, 911 reaches emergency help.
  • It does not rate how risky, safe or worthwhile any substance or practice is.

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Where does this come from?

Grade key: 1 = peer-reviewed publication or official document. A grade names the type of source, and the design and limits are given in the text. “Read in full” means Metanoia read every sentence on the date given, and any part not read is named.

Review due by 5 February 2027.

  1. Holze F, Caluori TV, Vizeli P, Liechti ME. Safety pharmacology of acute LSD administration in healthy subjects. Psychopharmacology 2021. DOI 10.1007/s00213-021-05978-6 PMID 34515824. Grade 1. Pooled analysis of four randomized trials from one laboratory. Text and abstract read in full 7 November 2026 (tables not read).
  2. Ley L, Holze F, Arikci D, et al. Comparative acute effects of mescaline, lysergic acid diethylamide, and psilocybin in a randomized, double-blind, placebo-controlled cross-over study in healthy participants. Neuropsychopharmacology 2023. DOI 10.1038/s41386-023-01607-2 PMID 37231080. Grade 1. Randomized crossover trial, 32 participants. Read in full 7 November 2026 (supplement not read).
  3. Holze F et al. Distinct acute effects of LSD, MDMA, and d-amphetamine in healthy subjects. Neuropsychopharmacology 2020. DOI 10.1038/s41386-019-0569-3 PMID 31733631. Grade 1. Randomized crossover trial, 28 participants. Text and tables read in full 7 November 2026 (supplement not read).
  4. Yerubandi A et al. Acute Adverse Effects of Therapeutic Doses of Psilocybin: A Systematic Review and Meta-Analysis. JAMA Netw Open 2024. DOI 10.1001/jamanetworkopen.2024.5960 PMID 38598236. Grade 1. Systematic review and meta-analysis of six trials. Read in full 7 November 2026 (supplementary figures not read).
  5. Hinkle JT et al. Adverse Events in Studies of Classic Psychedelics: A Systematic Review and Meta-Analysis. JAMA Psychiatry 2024. DOI 10.1001/jamapsychiatry.2024.2546 PMID 39230883. Grade 1. Systematic review of 114 studies, so the individual studies were not read. Text and tables read in full 7 November 2026 from the PMC page (supplement not read).
  6. D'Souza DC et al. Exploratory study of the dose-related safety, tolerability, and efficacy of dimethyltryptamine (DMT) in healthy volunteers and major depressive disorder. Neuropsychopharmacology 2022. DOI 10.1038/s41386-022-01344-y PMID 35660802. Grade 1. Small open-label study. Text read in full 7 November 2026 from the PMC page (supplement not read).
  7. Kwaśny A et al. Short-term safety and tolerability profile of 5-methoxy-N,N-dimethyltryptamine in human subjects: a systematic review of clinical trials. Front Psychiatry 2024. DOI 10.3389/fpsyt.2024.1477996 PMID 39364380. Grade 1. Systematic review of three trials, so the trials were not read. Read in full 7 November 2026; sections 3.2.1 and 3.2.2 and Tables 1 to 3 re-read 9 November 2026.
  8. Rouaud A et al. Microdosing psychedelics and the risk of cardiac fibrosis and valvulopathy: Comparison to known cardiotoxins. J Psychopharmacol 2024. DOI 10.1177/02698811231225609 PMID 38214279. Grade 1 by publication type. Narrative review, so the studies it summarizes were not read. Read in full 7 November 2026.
  9. Effinger DP, Schalk SS, King JL, et al. Assessing the potential cardiovascular risk of microdosing the psychedelic LSD in mice. ACS Pharmacol Transl Sci 2025. DOI 10.1021/acsptsci.5c00202 PMID 41789300. Grade 1. Preclinical study in mice. Read in full 7 November 2026.
  10. Yang KH et al. Association Between Lifetime Hallucinogen Use and Valvular Heart Disease: Findings from the All of Us Research Program. J Psychoactive Drugs 2026. DOI 10.1080/02791072.2026.2673845 PMID 42152600. Grade 1 by publication type. Exploratory cross-sectional study. Read in full 7 November 2026 from the PMC page (supplement not read).