RCT · 2026
Oral DMT plus harmine raised whole-brain glucose use by 12.5% in 14 healthy men
- Original title
- Global increases in brain glucose metabolism following acute N,N-dimethyltryptamine and harmine administration in healthy volunteers: A randomized [18F]FDG-PET study.
- Authors
- Egger K, Bozsak R, Aicher HD, et al.
- Journal
- Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, 2026
- Molecules
- DMT, Ayahuasca
- Conditions
- Healthy volunteers
- Participants
- 14
- Evidence grade
- Very low
- Source
- Read the original paper
The question
Does a psychedelic dose of DMT combined with harmine, a combination that mimics ayahuasca, change how much energy the brain uses?
What they did
Fourteen healthy men each received, on separate occasions, 90 mg of DMT plus 120 mg of harmine given through the cheek lining, and a placebo, in random order. Participants were not told which they were getting, though the researchers were (a single-blind, crossover design). Brain scans using [18F]FDG-PET, which tracks how fast brain tissue consumes glucose (its main fuel), were taken 100 to 170 minutes after dosing, during the peak of drug effects.
What they found
Whole-brain glucose consumption was 12.5% higher after DMT plus harmine than after placebo (t = 2.58, p = 0.011). Increases were widespread across the cortex, and were most pronounced in so-called higher-order brain networks. In exploratory analyses, higher blood levels of harmine were linked to higher brain glucose use, but blood levels of DMT and participants’ ratings of how intense the experience felt were not.
The fine print
Only 14 people took part, all of them healthy men, so the results may not apply to women, older adults or people with mental health conditions. The study was single-blind, and the strong subjective effects of a psychedelic make true blinding difficult. Brain glucose use is a biological marker, not a measure of mood, symptoms or any therapeutic benefit. This summary is based on the abstract alone.
What it means
A psychedelic dose of DMT with harmine increased the brain’s overall energy consumption in a small group of healthy men, echoing an earlier finding with psilocybin. It says nothing yet about whether the drug helps any medical condition.
Evidence grade: Very low. A randomized, placebo-controlled crossover design, but only 14 people, single-blind, and the outcome is a brain imaging measure rather than a health outcome.
This summary is based on the study’s published abstract.