Psychedelics for Physical Wellness
Updated October 2026: this page was written in 2024. The Medical News Today report it opened with is no longer available at its original web address, so the page now points to the study itself (Key study 1 at the end of this page). A new section on cancer research gathers the laboratory, animal and early human studies of psychedelics and of cannabis, with every item labeled by the kind of study it is, alongside the U.S. National Cancer Institute’s summary. Newer studies on physical health are listed under Key studies at the end.
Plants and fungi with psychedelic effects have been part of healing traditions for a very long time, including for the mind and spirit. Researchers have now started to ask whether psychedelic use has any link with the health of the body as well.
In one survey study, Simonsson and colleagues looked at answers from about 376,000 adults in the United States who took part in the National Survey on Drug Use and Health between 2005 and 2014. They reported that people who had tried a classic psychedelic even once, such as psilocybin, LSD, DMT, ayahuasca or mescaline, had lower odds of heart disease and of diabetes in the past year. A survey like this shows a link, not a cause, and the authors point out that whatever leads some people to try psychedelics might also lead them to healthier habits.
The authors suggest “several mechanisms through which classic psychedelics might influence cardiometabolic health”: healthier habits around diet, alcohol, tobacco and exercise; better mental health; effects on inflammation and the immune system; and action on serotonin receptors linked with heart and metabolic disease. These are ideas still to be tested. Earlier papers by the same research group had reported links with lower odds of being overweight or obese, and of high blood pressure (hypertension) in the past year.
A 2022 review by Teixeira and colleagues explores a related idea: that psychedelics such as psilocybin could help people make positive lifestyle changes, such as a better diet and more exercise. It sets out ideas to test, not trial results.
Later studies have added detail. In a 2022 survey of 2,822 adults, researchers reported that lifetime classic psychedelic use went with “more healthy tobacco-related and diet-related behavior”, and the authors suggested that insight during a psychedelic experience “may lead to positive health behavior change and better physical health in some domains”!
Simonsson O, Osika W, Carhart-Harris R, Hendricks PS. Associations between lifetime classic psychedelic use and cardiometabolic diseases. Sci Rep. 2021;11(1):14427. https://doi.org/10.1038/s41598-021-93787-4
Simonsson O, Sexton JD, Hendricks PS. Associations between lifetime classic psychedelic use and markers of physical health. J Psychopharmacol. 2021;35(4):447-452. https://doi.org/10.1177/0269881121996863
Simonsson O, Hendricks PS, Carhart-Harris R, Kettner H, Osika W. Association between lifetime classic psychedelic use and hypertension in the past year. Hypertension. 2021;77(5):1510-1516. https://doi.org/10.1161/HYPERTENSIONAHA.120.16715
Teixeira PJ, Johnson MW, Timmermann C, et al. Psychedelics and health behaviour change. J Psychopharmacol. 2022;36(1):12-19. https://doi.org/10.1177/02698811211008554
Simonsson O, Hendricks PS, Chambers R, Osika W, Goldberg SB. Classic psychedelics, health behavior, and physical health. Ther Adv Psychopharmacol. 2022;12:20451253221135363. https://doi.org/10.1177/20451253221135363
Cancer
Psychedelic-assisted therapy has evidence for reducing existential distress in people facing a life-limiting illness. Separately, some laboratory and single-case work has looked at whether psychedelic compounds affect tumour biology. That work is preclinical or anecdotal, and it does not show that psychedelics treat cancer in people. Nothing below is a treatment claim.
I have gathered the main cancer research on psychedelics and on cannabis below and labeled every item by the kind of study it is: cells (laboratory dishes), animals, survey of people, randomized trial in people, early-phase trial in people, case reports, review, guideline, or the U.S. National Cancer Institute’s summary. Each label shows where the research stands today, and all of it sits alongside, never in place of, care from a person’s own cancer team.
Cancer research: psychedelics
Survey of people (2021).
Among 171,766 U.S. adults, lifetime classic psychedelic use went with significantly higher odds of greater self-reported overall health and significantly lower odds of being overweight or obese!
Researchers used the 2015 to 2018 National Survey on Drug Use and Health to look at three markers of physical health: overall health, body weight, and having a heart condition and/or cancer. The study below reports a statistical association that did not reach significance. It does not show that psychedelic use lowers cancer risk: the authors reported lower odds of having a heart condition and/or cancer in the past 12 months for respondents who had tried a classic psychedelic at least once. The study’s main findings were on overall health and weight!
“As illustrated in the table, lifetime classic psychedelic use was associated with significantly lower odds of being overweight or obese as compared to having a normal weight.”
Simonsson O, Sexton JD, Hendricks PS. Associations between lifetime classic psychedelic use and markers of physical health. J Psychopharmacol. 2021;35(4):447-452. https://doi.org/10.1177/0269881121996863
Excerpt of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Simonsson O, Sexton JD, Hendricks PS. Associations between lifetime classic psychedelic use and markers of physical health. J Psychopharmacol. 2021;35(4):447-452. https://doi.org/10.1177/0269881121996863
Randomized trial in people with cancer diagnoses (2016): mood and quality of life.
About 80% of 51 people with life-threatening cancer diagnoses still showed clinically significant decreases in depressed mood and anxiety 6 months after high-dose psilocybin!
In a randomized, double-blind, cross-over trial, researchers studied 51 cancer patients with life-threatening diagnoses and symptoms of depression and/or anxiety, comparing a high dose of psilocybin with a very low, placebo-like dose. They reported that high-dose psilocybin produced large decreases in clinician- and self-rated depressed mood and anxiety, along with increases in quality of life, life meaning, and optimism, and decreases in death anxiety!
“At 6-month follow-up, these changes were sustained, with about 80% of participants continuing to show clinically significant decreases in depressed mood and anxiety.”
Griffiths RR, Johnson MW, Carducci MA, et al. Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: a randomized double-blind trial. J Psychopharmacol. 2016;30(12):1181-1197. https://doi.org/10.1177/0269881116675513
Abstract of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Griffiths RR, Johnson MW, Carducci MA, et al. Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: a randomized double-blind trial. J Psychopharmacol. 2016;30(12):1181-1197. https://doi.org/10.1177/0269881116675513
Cells and animals (mice), 2026.
LSD suppressed colorectal cancer growth in mice by boosting immune T cells, and a version that does not enter the brain made PD-1 immunotherapy work better!
In a 2026 study in the journal Cell, researchers reported that LSD, by targeting the serotonin receptor 5-HT2AR, enhances CD8+ T cell-mediated antitumor immunity (CD8+ T cells are immune cells that can attack tumors). The team then developed IHCH-8110, a compound that acts on the same receptor but does not enter the brain, and reported that it enhanced the efficacy of a type of immunotherapy (PD-1 blockade)! This was laboratory and mouse research, not a trial in people.
“Here, we show that by targeting the serotonin receptor 5-HT2AR, lysergic acid diethylamide (LSD) enhances CD8+ T cell-mediated antitumor immunity and suppresses colorectal cancer (CRC) growth.”
Wen Y, Tang L, Duan W, et al. Targeting peripheral 5-HT2AR enhances antitumor immunity in colorectal cancer. Cell. 2026;189(18):5688-5705.e13. https://doi.org/10.1016/j.cell.2026.07.028
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: Wen Y, Tang L, Duan W, et al. Targeting peripheral 5-HT2AR enhances antitumor immunity in colorectal cancer. Cell. 2026;189(18):5688-5705.e13. https://doi.org/10.1016/j.cell.2026.07.028
Animals (mice), 2026: a chemotherapy side effect.
Just two doses of psilocybin before chemotherapy prevented nerve damage in mouse models, without impairing the chemotherapy’s antitumor effect!
A 2026 study in Science looked at nerve damage caused by chemotherapy (chemotherapy-induced peripheral neuropathy, or CIPN). The researchers reported that as little as two doses of psilocybin before chemotherapy durably prevented the onset of this nerve damage in their models, “without impairing antitumor efficacy”, meaning the chemotherapy still worked against the tumors! Nature’s news report on the study was headlined “Magic-mushroom compound blocks a severe side effect of chemotherapy in mice”. This is a finding about a side effect, in mice.
“This stabilization of peripheral axonal energy balance establishes psilocybin as a first-in-class prophylactic agent for CIPN while also preserving central neural function.”
Heles M, Pasvolsky L, Sathishkumar H, et al. Psilocybin prevents chemotherapy-induced peripheral neuropathy through mitochondrial trafficking preservation. Science. 2026;393(6815):eaec6116. https://doi.org/10.1126/science.aec6116
Kozlov M. Magic-mushroom compound blocks a severe side effect of chemotherapy in mice. Nature. Published online September 3, 2026. https://doi.org/10.1038/d41586-026-02744-6
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: Heles M, Pasvolsky L, Sathishkumar H, et al. Psilocybin prevents chemotherapy-induced peripheral neuropathy through mitochondrial trafficking preservation. Science. 2026;393(6815):eaec6116. https://doi.org/10.1126/science.aec6116
Cells, 2013.
DMT and tryptamine increased the cytotoxic activity of immune cells against human glioma cells in the dish!
A 2013 laboratory study tested DMT and tryptamine on IDO, an enzyme that helps tumors escape the immune system, using human glioma (brain tumor) cells and immune cells from blood. The researchers reported that DMT and tryptamine inhibited IDO, and they concluded that this contributed to a more effective tumor-reactive response by the immune cells in the dish! This was laboratory work in dishes.
“TRY and DMT increased the cytotoxic activity of peripheral blood mononuclear cells (PBMCs) in co-culture assays.”
Tourino MC, de Oliveira EM, Bellé LP, et al. Tryptamine and dimethyltryptamine inhibit indoleamine 2,3 dioxygenase and increase the tumor-reactive effect of peripheral blood mononuclear cells. Cell Biochem Funct. 2013;31(5):361-364. https://doi.org/10.1002/cbf.2980
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: Tourino MC, de Oliveira EM, Bellé LP, et al. Tryptamine and dimethyltryptamine inhibit indoleamine 2,3 dioxygenase and increase the tumor-reactive effect of peripheral blood mononuclear cells. Cell Biochem Funct. 2013;31(5):361-364. https://doi.org/10.1002/cbf.2980
Review, 2016.
Human studies found that ayahuasca altered the number and distribution of blood immune cells in a way that can increase antiviral and anti-tumor immunity!
Preclinical work has examined possible anti-tumour activity in ayahuasca’s constituents. None of it has been tested as a cancer treatment in people. Frecska and colleagues point to human studies in which ayahuasca changed the numbers of some immune cells in the blood, such as natural killer cells, and they suggest this might support immunity against viruses and tumors!
“The possible anti-cancer activity of the decoction makes it a promising candidate for further researches in novel pharmacotherapies (Schenberg, 2013).”
Frecska E, Bokor P, Winkelman M. The therapeutic potentials of ayahuasca: possible effects against various diseases of civilization. Front Pharmacol. 2016;7:35. https://doi.org/10.3389/fphar.2016.00035
Excerpt of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Frecska E, Bokor P, Winkelman M. The therapeutic potentials of ayahuasca: possible effects against various diseases of civilization. Front Pharmacol. 2016;7:35. https://doi.org/10.3389/fphar.2016.00035
Review, 2015.
Circulating natural killer (NK) cells, immune cells involved in anti-viral and anti-cancer responses, increased significantly in human studies of ayahuasca, according to this review of psychedelics and the immune system!
A review of psychedelics and the immune system describes classic psychedelics changing immune responses “by altering signaling pathways involved in inflammation, cellular proliferation, and cell survival”, and names cancer among the diseases where this emerging field is being explored. It also reports that in human studies of ayahuasca the number of circulating NK cells increased significantly!
“Notably, the number of circulating NK cells, a cell type involved in anti-viral and anti-cancer immune responses, increased significantly (105, 106).”
Szabo A. Psychedelics and immunomodulation: novel approaches and therapeutic opportunities. Front Immunol. 2015;6:358. https://doi.org/10.3389/fimmu.2015.00358
Excerpt of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Szabo A. Psychedelics and immunomodulation: novel approaches and therapeutic opportunities. Front Immunol. 2015;6:358. https://doi.org/10.3389/fimmu.2015.00358
Review, 2015.
Sigma receptors are over-expressed in tumors, and their ligands induce significant cell death only in tumor tissue!
DMT has also been linked with sigma receptors, proteins found in high amounts in many tumors. A 2015 review notes that the body’s own binders for these receptors “may include the hallucinogen N,N-dimethyltryptamine (DMT)”, and that drugs acting on sigma receptors can cause cell death in tumor tissue. Finally, the review describes tracers that show sigma receptors on PET scans, and tiny particles that use sigma receptors to carry cancer drugs, which at the time had been tried only in animals.
“Although sigma receptors are over-expressed in tumors and up-regulated in rapidly dividing normal tissue, their ligands induce significant cell death only in tumor tissue.”
van Waarde A, Rybczynska AA, Ramakrishnan NK, Ishiwata K, Elsinga PH, Dierckx RA. Potential applications for sigma receptor ligands in cancer diagnosis and therapy. Biochim Biophys Acta. 2015;1848(10 Pt B):2703-2714. https://doi.org/10.1016/j.bbamem.2014.08.022
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: van Waarde A, Rybczynska AA, Ramakrishnan NK, Ishiwata K, Elsinga PH, Dierckx RA. Potential applications for sigma receptor ligands in cancer diagnosis and therapy. Biochim Biophys Acta. 2015;1848(10 Pt B):2703-2714. https://doi.org/10.1016/j.bbamem.2014.08.022
Case reports, gathered in a review (2013).
At least nine case reports of people using ayahuasca with different cancers, and several were considered improvements!
A 2013 review by Eduardo Schenberg, shown below, found at least nine case reports of people using ayahuasca with prostate, brain, ovarian, uterine, stomach, breast and colon cancers, and several of these were considered improvements. He presented a theoretical model for these effects at the cellular, molecular and psychosocial levels, and called for research into the safety and efficacy of ayahuasca!
“The proposed model, based on the molecular and cellular biology of ayahuasca's known active components and the available clinical reports, suggests that these accounts may have consistent biological underpinnings.”
Schenberg EE. Ayahuasca and cancer treatment. SAGE Open Med. 2013;1:2050312113508389. https://doi.org/10.1177/2050312113508389 · Screenshot of the published record (PubMed).
Cancer research: cannabis
The same question has been asked about cannabis, and there the research has gone further, into small trials in people. Cannabis is not a classic psychedelic, but it belongs to the same conversation about plant medicines and cancer, so the main studies are set out here, each labeled by the kind of study it is.
The U.S. National Cancer Institute’s summary.
A meta-analysis of 34 laboratory and animal studies in glioma: all but one confirmed that cannabinoids selectively kill tumor cells!
The National Cancer Institute’s summary for health professionals (latest update May 13, 2025) reports that “Cannabinoids may cause antitumor effects by various mechanisms, including induction of cell death, inhibition of cell growth”, and that CBD together with THC may enhance the antitumor activity of temozolomide, a chemotherapy drug, in some mouse models of cancer! The summary also gives the regulatory status as of that update: “The U.S. Food and Drug Administration has not approved Cannabis as a treatment for cancer or any other medical condition.”
“A meta-analysis of 34 in vitro and in vivo studies of cannabinoids in glioma reported that all but one study confirmed that cannabinoids selectively kill tumor cells.”
PDQ Integrative, Alternative, and Complementary Therapies Editorial Board. Cannabis and Cannabinoids (PDQ®)–Health Professional Version. National Cancer Institute. Updated May 13, 2025. Accessed October 27, 2026. https://www.cancer.gov/about-cancer/treatment/cam/hp/cannabis-pdq
Page of the U.S. National Cancer Institute (public domain), key sentence highlighted in yellow. Source: PDQ Integrative, Alternative, and Complementary Therapies Editorial Board. Cannabis and Cannabinoids (PDQ®)–Health Professional Version. National Cancer Institute. Updated May 13, 2025. Accessed October 27, 2026. https://www.cancer.gov/about-cancer/treatment/cam/hp/cannabis-pdq
Review of cells and animals (2022).
A large body of preclinical data: cannabinoids inhibited tumour cell proliferation, invasion and metastasis, angiogenesis and chemoresistance, and induced apoptosis and autophagy in laboratory research!
A 2022 review of preclinical research reported that cannabinoid compounds have been successfully tested as a systemic therapeutic option in a number of preclinical models over the past decades. It describes cannabinoids as potential combination partners for established chemotherapeutic agents, and points to promising compounds beyond THC, such as the non-psychoactive phytocannabinoid cannabidiol!
“Accordingly, there is considerable evidence for cannabinoid-mediated inhibition of tumour cell proliferation, tumour invasion and metastasis, angiogenesis and chemoresistance, as well as induction of apoptosis and autophagy.”
Hinz B, Ramer R. Cannabinoids as anticancer drugs: current status of preclinical research. Br J Cancer. 2022;127(1):1-13. https://doi.org/10.1038/s41416-022-01727-4
Abstract of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Hinz B, Ramer R. Cannabinoids as anticancer drugs: current status of preclinical research. Br J Cancer. 2022;127(1):1-13. https://doi.org/10.1038/s41416-022-01727-4
Animals (mice), 2011.
THC with temozolomide exerted a strong antitumoral action in glioma xenografts in mice, including tumors that are resistant to temozolomide!
In glioma xenografts (human brain tumor cells grown in mice), researchers reported that THC combined with temozolomide, the standard chemotherapy for glioblastoma, “exerts a strong antitumoral action in glioma xenografts, an effect that is also observed in tumors that are resistant to TMZ treatment”, TMZ being temozolomide.
“Moreover, treatment with TMZ and submaximal doses of THC and CBD produced a strong antitumoral action in both TMZ-sensitive and TMZ-resistant tumors.”
Torres S, Lorente M, Rodríguez-Fornés F, et al. A combined preclinical therapy of cannabinoids and temozolomide against glioma. Mol Cancer Ther. 2011;10(1):90-103. https://doi.org/10.1158/1535-7163.MCT-10-0688
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: Torres S, Lorente M, Rodríguez-Fornés F, et al. A combined preclinical therapy of cannabinoids and temozolomide against glioma. Mol Cancer Ther. 2011;10(1):90-103. https://doi.org/10.1158/1535-7163.MCT-10-0688
Early-phase trial in people (2006).
In a first pilot trial of 9 patients with recurrent glioblastoma, THC delivered into the tumor was safe, and tumour-cell Ki67 staining decreased in the 2 patients tested!
The first test in people was a pilot study in which “nine patients with recurrent glioblastoma multiforme were administered THC intratumoraly”, after standard treatment had failed. Its main aim was safety, and the researchers reported that cannabinoid delivery was safe and could be achieved without overt psychoactive effects!
“Delta(9)-Tetrahydrocannabinol inhibited tumour-cell proliferation in vitro and decreased tumour-cell Ki67 immunostaining when administered to two patients.”
Guzmán M, Duarte MJ, Blázquez C, et al. A pilot clinical study of Delta9-tetrahydrocannabinol in patients with recurrent glioblastoma multiforme. Br J Cancer. 2006;95(2):197-203. https://doi.org/10.1038/sj.bjc.6603236
Abstract of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Guzmán M, Duarte MJ, Blázquez C, et al. A pilot clinical study of Delta9-tetrahydrocannabinol in patients with recurrent glioblastoma multiforme. Br J Cancer. 2006;95(2):197-203. https://doi.org/10.1038/sj.bjc.6603236
Early-phase trial in people (2021).
83% vs 44% survival at 1 year in Part 2 of a randomized early-phase trial: 12 people given nabiximols, a cannabis-based spray, and 9 given placebo, all alongside temozolomide!
A small trial in 27 people with glioblastoma that had come back added nabiximols, a cannabis-based mouth spray, to temozolomide chemotherapy; 21 of them were randomized to nabiximols or a placebo. The researchers reported that survival at 1 year was 83% for nabiximols- and 44% for placebo-treated patients, and that nabiximols had acceptable safety and tolerability with no drug-drug interaction identified! The trial was sponsored by GW Research Ltd.
“The observed survival differences support further exploration in an adequately powered randomised controlled trial.”
Twelves C, Sabel M, Checketts D, et al. A phase 1b randomised, placebo-controlled trial of nabiximols cannabinoid oromucosal spray with temozolomide in patients with recurrent glioblastoma. Br J Cancer. 2021;124(8):1379-1387. https://doi.org/10.1038/s41416-021-01259-3
Abstract of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Twelves C, Sabel M, Checketts D, et al. A phase 1b randomised, placebo-controlled trial of nabiximols cannabinoid oromucosal spray with temozolomide in patients with recurrent glioblastoma. Br J Cancer. 2021;124(8):1379-1387. https://doi.org/10.1038/s41416-021-01259-3
Guideline (2024).
An expert panel reviewed 13 systematic reviews and 5 more primary studies, and found that cannabis and/or cannabinoids may improve refractory chemotherapy-induced nausea and vomiting!
The American Society of Clinical Oncology’s guideline on cannabis for adults with cancer drew on 13 systematic reviews and five additional primary studies (four randomized controlled trials and one cohort study). It provides strategies for open, nonjudgmental communication between clinicians and adults with cancer about the use of cannabis and/or cannabinoids!
“Cannabis and/or cannabinoids may improve refractory, chemotherapy-induced nausea and vomiting when added to guideline-concordant antiemetic regimens.”
Braun IM, Bohlke K, Abrams DI, et al. Cannabis and cannabinoids in adults with cancer: ASCO guideline. J Clin Oncol. 2024;42(13):1575-1593. https://doi.org/10.1200/JCO.23.02596
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: Braun IM, Bohlke K, Abrams DI, et al. Cannabis and cannabinoids in adults with cancer: ASCO guideline. J Clin Oncol. 2024;42(13):1575-1593. https://doi.org/10.1200/JCO.23.02596
Mice and an observational study in people (2023).
Mice given THC with an anti-PD-1 antibody lived a median of 54 days, against 31 days with the antibody alone!
A 2023 study combined mouse experiments with a look at 201 people with metastatic non-small cell lung cancer who were treated with pembrolizumab as a first-line monotherapy. The researchers reported that median survival of the mice receiving a control vehicle, THC, an anti-PD-1 antibody or their combination was 21, 24, 31 and 54 days, respectively!
“Preclinical and clinical data suggest no deleterious effect of cannabis on the activity of pembrolizumab as first-line monotherapy for advanced NSCLC.”
Waissengrin B, Leshem Y, Taya M, et al. The use of medical cannabis concomitantly with immune checkpoint inhibitors in non-small cell lung cancer: a sigh of relief? Eur J Cancer. 2023;180:52-61. https://doi.org/10.1016/j.ejca.2022.11.022
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: Waissengrin B, Leshem Y, Taya M, et al. The use of medical cannabis concomitantly with immune checkpoint inhibitors in non-small cell lung cancer: a sigh of relief? Eur J Cancer. 2023;180:52-61. https://doi.org/10.1016/j.ejca.2022.11.022
Neurodegenerative Diseases
Ayahuasca has been suggested, so far only in theory, as something worth studying in neuropsychiatric illnesses such as:
Alzheimer’s disease,
Parkinson’s disease,
amyotrophic lateral sclerosis (ALS),
bipolar disorder,
and other long-term illnesses: atherosclerosis, diabetes, cancer, autoimmune and cardiovascular disorders.
Frecska and colleagues explain that a kind of stress inside cells is thought to play a key role in all of these illnesses. They write:
“All of these disorders may have common mechanism: failure of protein homeostasis.”
In plain words, cells may struggle to keep their proteins folded and working. The authors expect that DMT, acting on a receptor inside cells called the sigma-1 receptor, might help cells handle this stress. They offer this as an idea for future research, not as something that has been shown.
However, it is not purely DMT responsible for ayahuasca’s possible beneficial effects. The other active compounds in ayahuasca are “the β-carboline alkaloids, which act as selective, reversible MAO-A inhibitors”. Without them, the DMT in ayahuasca taken by mouth would be broken down before reaching the brain. The authors also mention early signs that these alkaloids have medicinal effects of their own, and that, according to ethnographic observations, many Indigenous users of ayahuasca give their sacramental respect to the vine, B. caapi, rather than to the DMT-containing plant.
Frecska E, Bokor P, Winkelman M. The therapeutic potentials of ayahuasca: possible effects against various diseases of civilization. Front Pharmacol. 2016;7:35. https://doi.org/10.3389/fphar.2016.00035
Key studies (updated October 2026)
Study 1. Heart disease and diabetes in about 376,000 U.S. survey respondents, with and without classic psychedelic use (Simonsson, 2021)
23% lower odds of heart disease and 12% lower odds of diabetes in the past year among U.S. adults who had tried a classic psychedelic at least once!
In a cross-sectional analysis of the U.S. National Survey on Drug Use and Health from 2005 to 2014, researchers compared adults who had ever tried a classic psychedelic with adults who had not. They reported that people who had tried one “had lower odds of heart disease in the past year” (adjusted odds ratio 0.77, 95% CI 0.65–0.92) and “lower odds of diabetes in the past year” (0.88, 95% CI 0.78–0.99)!
“As illustrated below, lifetime classic psychedelic use was uniquely associated with a 23% lower odds of heart disease in the past year and a 12% lower odds of diabetes in the past year.”
Source: Simonsson O, Osika W, Carhart-Harris R, Hendricks PS. Associations between lifetime classic psychedelic use and cardiometabolic diseases. Sci Rep. 2021;11(1):14427. https://doi.org/10.1038/s41598-021-93787-4
Excerpt of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Simonsson O, Osika W, Carhart-Harris R, Hendricks PS. Associations between lifetime classic psychedelic use and cardiometabolic diseases. Sci Rep. 2021;11(1):14427. https://doi.org/10.1038/s41598-021-93787-4
Study 2. Ayahuasca in 18 prospective studies, mostly of retreat volunteers (Haupt, 2026)
18 prospective studies: long-term changes in wellbeing, depression, substance misuse, cognitive flexibility and prosocial behavior after ayahuasca, and one study found a decrease in physical pain symptoms!
In a systematic review, researchers gathered 18 prospective studies that followed people over time after drinking ayahuasca, most of them recruiting volunteers at ayahuasca retreat centers. They reported long-term changes in wellbeing and quality of life, in depression and other psychiatric symptoms, and in substance misuse, with mental health improvements noted at the population level!
“Across studies, long-term changes were noted in wellbeing/quality of life, depression and other psychiatric symptoms, substance misuse, cognitive flexibility, personality, and prosocial behavior.”
Source: Haupt MJ, Carra S, Boehnke KF, Aday JS. Preliminary effects of ayahuasca on mental and physical health: A systematic review of prospective studies. Prog Neuropsychopharmacol Biol Psychiatry. 2026;145:111634. https://doi.org/10.1016/j.pnpbp.2026.111634
Abstract of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Haupt MJ, Carra S, Boehnke KF, Aday JS. Preliminary effects of ayahuasca on mental and physical health: A systematic review of prospective studies. Prog Neuropsychopharmacol Biol Psychiatry. 2026;145:111634. https://doi.org/10.1016/j.pnpbp.2026.111634
Study 3. Psilocybin and smoking cessation in 15 smokers (Johnson, 2014)
12 of 15 smokers (80%) were smoking-abstinent at 6-month follow-up after psilocybin within a structured 15-week cessation program!
In a pilot study, researchers gave psilocybin to 15 nicotine-dependent smokers as part of a structured 15-week smoking cessation treatment program. They reported that biomarkers and self-report measures showed that 12 of 15 participants (80%) had seven-day point prevalence abstinence at 6-month follow-up!
“The observed smoking cessation rate substantially exceeds rates commonly reported for other behavioral and/or pharmacological therapies (typically <35%).”
Source: Johnson MW, Garcia-Romeu A, Cosimano MP, Griffiths RR. Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction. J Psychopharmacol. 2014;28(11):983-992. https://doi.org/10.1177/0269881114548296
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: Johnson MW, Garcia-Romeu A, Cosimano MP, Griffiths RR. Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction. J Psychopharmacol. 2014;28(11):983-992. https://doi.org/10.1177/0269881114548296
Study 4. DMT in 5 early-phase trials of healthy volunteers and people with depression (Swieczkowski, 2025)
No serious adverse events were reported across 5 early-phase DMT trials, and DMT was generally well-tolerated!
In a systematic review, researchers gathered five early-phase clinical trials that gave DMT by vein, by inhalation, by mouth or by nose, mostly to healthy volunteers and some to people with major depressive disorder. They reported that the effects noted were short-lived, and the authors described DMT as a fast-acting psychedelic with rapid onset and short duration!
“No serious adverse events were reported, and DMT was generally well-tolerated.”
Source: Swieczkowski D, Kwaśny A, Cubała WJ. Safety and tolerability of NN-dimethyltryptamine (DMT) in healthy volunteers and Major Depressive Disorder (MDD) patients: A systematic review of early-phase clinical trials. Prog Neuropsychopharmacol Biol Psychiatry. 2025;140:111419. https://doi.org/10.1016/j.pnpbp.2025.111419
Quotation from the abstract of the published study (text from Europe PMC), highlighted in yellow. Source: Swieczkowski D, Kwaśny A, Cubała WJ. Safety and tolerability of NN-dimethyltryptamine (DMT) in healthy volunteers and Major Depressive Disorder (MDD) patients: A systematic review of early-phase clinical trials. Prog Neuropsychopharmacol Biol Psychiatry. 2025;140:111419. https://doi.org/10.1016/j.pnpbp.2025.111419
Study 5. Psilocybin in 528 people with depression or anxiety in six randomized trials (Yerubandi, 2024)
Six randomized, double-blind trials with 528 participants: the acute effects of therapeutic psilocybin appeared tolerable and resolved within 48 hours!
In a systematic review and meta-analysis, researchers pooled six randomized, double-blind trials of psilocybin for depression or anxiety, with 528 participants in total, to look at short-term safety. They reported that psilocybin use was not associated with risk of paranoia and transient thought disorder!
“In this meta-analysis, the acute adverse effect profile of therapeutic single-dose psilocybin appeared to be tolerable and resolved within 48 hours.”
Source: Yerubandi A, Thomas JE, Bhuiya NMMA, et al. Acute Adverse Effects of Therapeutic Doses of Psilocybin: A Systematic Review and Meta-Analysis. JAMA Netw Open. 2024;7(4):e245960. https://doi.org/10.1001/jamanetworkopen.2024.5960
Abstract of the published study (text from Europe PMC), key sentence highlighted in yellow. Source: Yerubandi A, Thomas JE, Bhuiya NMMA, et al. Acute Adverse Effects of Therapeutic Doses of Psilocybin: A Systematic Review and Meta-Analysis. JAMA Netw Open. 2024;7(4):e245960. https://doi.org/10.1001/jamanetworkopen.2024.5960
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