The risk of chronic psychedelic and MDMA microdosing for valvular heart disease

Abstract

Psychedelic microdosing is the practice of taking very low doses of psychedelic substances, typically over a longer period of time. The long-term safety of chronic microdosing is relatively uncharacterized, but valvular heart disease (VHD) has been proposed as a potential risk due to activation of the serotonin 5-HT 2B receptor. However, this risk has not yet been comprehensively assessed. This analysis searched for all relevant in vitro, animal, and clinical studies related to the VHD risk of lysergic acid diethylamide (LSD), psilocybin, mescaline, N,N-dimethyltryptamine (DMT), and the non-psychedelic 3,4-methylenedioxymethamphetamine (MDMA). All five compounds and some metabolites could bind to the 5-HT 2B receptor with potency equal to or greater than that of the 5-HT 2A receptor, the primary target of psychedelics. All compounds were partial agonists at the 5-HT 2B receptor with the exception of mescaline, which could not be adequately assessed due to low potency. 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. We conclude that VHD is a potential risk with chronic psychedelic microdosing, but further studies are necessary to better define this risk.

In the evidence

This study is part of the evidence base for 2 syntheses in the library. Here is how each one recorded it.

• State of the evidence: LSD and microdosing ?Unclear

  Concludes that chronic psychedelic microdosing is a potential risk for valvular heart disease via 5-HT2B receptor activation, but no appropriately designed animal or clinical studies were found.

  Synthesized October 22, 2026

• State of the evidence: Psilocybin and microdosing ↓Opposes

  Psychedelics and MDMA can bind the 5-HT2B receptor, and chronic microdosing is a potential but unconfirmed risk for valvular heart disease, with no adequately designed animal or clinical studies found.

  Synthesized October 22, 2026

Comparable studies

Other narrative reviews on LSD and microdosing, most cited first.