Long-term microdosing and heart valve disease: every psychedelic tested hits the receptor behind the risk
A review of lab, animal and human data found LSD, psilocybin, DMT, MDMA and their metabolites act on the 5-HT2B receptor, the one behind drug-induced valve damage. No study has tested valve risk from psychedelic microdosing.
Weak or heavily disputed. Treat as a question, not an answer. how we score evidence
Caveat on this rating: A mechanistic risk assessment; no study designed to measure valve risk from psychedelic microdosing exists, and safety margins were wider than for known valve-damaging drugs.
The safety question that daily or every-few-days dosing raises and no trial has answered.
Significant findings
Tagen and colleagues (Journal of Psychopharmacology, 2023) searched for in vitro, animal and clinical studies on the risk of valvular heart disease (VHD) from LSD, psilocybin, mescaline, DMT and the non-psychedelic MDMA. Several earlier drugs that damaged heart valves did so through the serotonin 5-HT2B receptor. "All five compounds and some metabolites could bind to the 5-HT2B receptor with potency equal to or greater than that of the 5-HT2A receptor, the primary target of psychedelics. All compounds were partial agonists at the 5-HT2B receptor with the exception of mescaline, which could not be adequately assessed due to low potency."
On size: "Safety margins relative to the maximum plasma concentrations from typical microdoses were greater than known valvulopathogens, but not without potential risk. No animal or clinical studies appropriately designed to evaluate VHD risk were found for the four psychedelics. However, there is some clinical evidence that chronic ingestion of full doses of MDMA is associated with VHD."
The other direction
This is a risk assessment, not evidence of harm: no case series of valve disease from psychedelic microdosing is reported, and the safety margins were wider than for drugs known to damage valves. The authors conclude only that VHD "is a potential risk with chronic psychedelic microdosing, but further studies are necessary to better define this risk." The abstract carries no funding or conflict statement and the full text was not read.
What this does not show
It does not show that any microdoser has valve damage, or that occasional full-dose use carries this risk. It is not a diagnosis and not a treatment instruction.
Worth asking
If I have taken anything regularly for months, should a heart murmur or breathlessness be checked?
Source
The risk of chronic psychedelic and MDMA microdosing for valvular heart disease — Tagen M, Mantuani D, van Heerden L, Holstein A, Klumpers LE, Knowles R (2023)
Reputable peer-reviewed journal
Read the source: https://doi.org/10.1177/02698811231190865
DOI: 10.1177/02698811231190865
How this was scored
- Study design
- Narrative review
- Funding
- Funding not disclosed
- Published in
- Reputable peer-reviewed journal
- Sample size
- not recorded
- Preregistered
- not recorded
- Conflicts disclosed
- not recorded
- Independent of proponent
- not recorded
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published October 21, 2026.
Questions
How strong is the evidence behind this?
veisund rates this source "contested". Weak or heavily disputed. Treat as a question, not an answer. It scores 33 out of 100 on our published rubric. One caveat travels with that badge: A mechanistic risk assessment; no study designed to measure valve risk from psychedelic microdosing exists, and safety margins were wider than for known valve-damaging drugs. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
The risk of chronic psychedelic and MDMA microdosing for valvular heart disease — Tagen M, Mantuani D, van Heerden L, Holstein A, Klumpers LE, Knowles R (2023). Published in: Reputable peer-reviewed journal. DOI: 10.1177/02698811231190865. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Narrative review. Funding: Funding not disclosed. Independence from the proponent is not recorded. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.