Psychedelic microdosing in the US: what the survey showed and what it did not

**Research review** ## The hook Microdosing gets more attention every month, and headlines about it read like instructions. The recent US survey, however, measured how many people report it. It does not show that long-term use is safe. Here is what was measured and what was not. ## What is known, what is not, and the risks **Known:** the 2026 RAND survey of 10,122 US adults found microdosing among people who use psychoactive substances. According to the report text, 69% of past-year psilocybin users reported microdosing [S-001]. **Known from laboratory work:** a 2024 review of controlled studies (14 studies, all with LSD) reported no serious adverse effects. But those studies are short and cover a narrow range of substances and conditions [S-002]. **Not known:** whether regular use over months or years is safe, and how it affects the heart. The heart question remains a hypothesis: a 2024 risk review notes that psychedelics resemble drugs that were linked to cardiac fibrosis and valve damage with regular use, but the review found few studies of long-term microdosing safety and explicitly notes a lack of data on valve risk specifically [S-003]. **Risks:** illegal supply and unknown product content; interactions with medicines, including antidepressants and heart medication; long-term cardiac risks that have not been studied. If you have heart disease, a mental health condition, or take medication, do not start anything without consulting a doctor. **Does not follow from these sources:** that microdosing is safe; that it improves mood or work; any dose or schedule. This article contains no dosing and gives no instructions. ## What the survey measured The RAND survey assessed use of 11 psychedelics and the prevalence of microdosing for psilocybin, LSD and MDMA. The authors describe how US states are debating alternatives to prohibition for non-medical use. This is a descriptive study: it shows prevalence and does not answer whether the practice helps or harms [S-001]. ## What controlled studies say The 2024 review selected studies with double-blind placebo control, where the investigator supplied the drug. All 14 studies involved LSD. Effects were observed on blood pressure, sleep, mood and time perception, but the review does not draw firm conclusions about benefit in everyday life [S-002]. ## Why the heart question is still open The fibrosis and valve-damage hypothesis rests on molecular similarity to drugs that caused such problems with regular use in the past. The authors themselves call for safety evaluation of microdosing in future studies [S-003]. That is a reason for caution and further research, not proven harm. ## What next If you are considering psychoactive substances, talk to a doctor, especially if you have heart or mental health conditions or take medication. If you already use them, do not stop prescribed medicines or change a regimen based on this article without a doctor. If you need help, contact an addiction specialist or psychiatrist. ## Question for readers Which questions about psychedelics and research would you like to see in future pieces? Write in the comments, but take medical questions to a professional. ## What was checked—and what the claims mean | Claim | Status | Source | |---|---|---| | Survey of 10,122 US adults, 2025 | checked against abstract and text retrieved via Europe PMC | S-001 | | 69% of past-year psilocybin users reported microdosing | from RAND page text; no snapshot kept, page returned 403 | S-001 | | The survey did not collect safety data | checked against the design description | S-001 | | 14 controlled studies, all LSD, no serious adverse effects reported | checked against abstract | S-002 | | Microdosing carries a risk of cardiac fibrosis and valve damage | hypothesis by analogy, not an established effect | S-003 | | Long-term safety is not established | conclusion drawn from the sources above | S-001, S-002, S-003 | | Doses and schedules | not given | — | No medical reviewer has been assigned and no medical review date is recorded. This article is not medical advice and does not replace a consultation with a doctor. **Author:** Serge Luboff.