Summary: For decades, the notion that the mammalian brain produces N,N-dimethyltryptamine (DMT)—often called “the spirit molecule”—has been central to discussions about dreams, near-death experiences, and endogenous psychedelics. A new study from researchers at the University of Southern Denmark and Bern University Hospital challenges that view. Using highly sensitive quantitative methods in adult rats, the team found no detectable DMT in selected brain regions, even when metabolic breakdown was pharmacologically blocked. The data indicate that DMT is unlikely to act as a classical neurotransmitter within the brain’s serotonin system.
Key Findings
- No Detectable Endogenous DMT: The researchers did not detect measurable levels of naturally occurring DMT in the adult rat brain, despite pretreatments intended to prevent its metabolic degradation.
- Not Stored in Serotonin Terminals: Experiments designed to reveal whether DMT can be stored in serotonin-releasing nerve endings found no meaningful retention, arguing against DMT functioning as a serotonin co-transmitter.
- High Sensitivity Methods: Trace-detection analytical techniques were employed to capture even very small quantities, yet endogenous DMT remained below the limits of detection.
- INMT Presence Is Not Proof of Production: Although the enzyme indolethylamine N‑methyltransferase (INMT), which can synthesize DMT, exists in mammalian tissue, the presence of that enzyme does not necessarily mean the brain routinely produces DMT in measurable amounts.
- Scope and Limits: The study narrows where DMT might originate or act but does not exclude its presence in other tissues or during rare physiological states not examined here.
Research teams and approach
The study was led by Mikael Palner (University of Southern Denmark) and Paul Cumming (Bern University Hospital). The team used quantitative chemical analyses to examine DMT and related metabolites across multiple brain regions in adult rats. They also tested whether administered DMT could be taken up into serotonergic neurons through the serotonin transporter (SERT) or be sequestered by vesicles via the vesicular monoamine transporter 2 (VMAT2).
What the results imply
The results strongly suggest that, in adult rats, DMT is neither produced at measurable levels nor stored in serotonin terminals. Blocking monoamine oxidase to prevent normal DMT breakdown did not reveal an endogenous pool, and pharmacological manipulation of serotonin uptake or vesicular storage did not lead to significant retention of administered DMT. Consequently, DMT is unlikely to act as a classical neurotransmitter or co-transmitter within the serotonin system under normal adult conditions examined in this study.
Possible alternatives and remaining questions
If DMT has a biological role, it may involve non-serotonergic cell types, peripheral tissues (for example, lungs or other organs), or specific physiological or developmental states not covered by this experiment (such as birth, extreme stress, or death). The study helps narrow the search by excluding the serotonin terminal system in adult rat brain as a primary site of synthesis or storage.
What is DMT?
N,N-dimethyltryptamine (DMT): a naturally occurring psychedelic compound found in some plants and a principal active ingredient in ayahuasca. It is chemically related to serotonin and can be synthesized in mammalian tissue by the enzyme INMT. In popular culture, DMT has been associated with vivid dreaming and near-death narratives, but the current evidence does not support routine production or storage of measurable DMT in adult rat serotonin systems.
Study highlights — methods and design
Researchers quantified DMT and its acidic metabolite 3-indoleacetic acid (3-IAA) across multiple brain regions. They tested hypotheses that inhibiting monoamine oxidase (with pargyline) would reveal accumulated endogenous DMT, and that inhibiting transport of acidic metabolites (with probenecid) would alter 3-IAA levels. To explore storage, the team evaluated whether blocking plasma membrane serotonin uptake (with escitalopram) or vesicular monoamine transport (with dihydrotetrabenazine) affected retention of exogenously administered DMT combined with harmine.
Time-course measurements after DMT plus harmine administration showed peak brain DMT concentrations at approximately 45 minutes and peak 3-IAA at around 60 minutes, with exogenous DMT largely cleared by 210 minutes. Despite these manipulations, endogenous DMT concentrations remained below detection limits, while modest increases in 3-IAA suggested some metabolic activity from tryptamine in regions like striatum.
Frequently Asked Questions
A: No. The study specifically examined adult rat brain regions and the serotonin system. It makes it much less likely that the adult brain continuously produces and stores measurable DMT in serotonergic terminals, but it does not exclude transient production in other tissues or during rare physiological events.
A: Popular theories, notably promoted in the 1990s, proposed that DMT could surge during extreme states, possibly released from structures such as the pineal gland. The current findings suggest that the conventional neural machinery for storing and releasing DMT like a typical neurotransmitter is not present in the serotonin terminals examined here.
A: Many brain receptors, such as 5-HT2A, evolved to detect endogenous serotonin. DMT can bind to and activate these receptors because its structure resembles serotonin, allowing it to elicit psychedelic effects when introduced from outside the brain or possibly from other sources.
Editorial notes
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was added by editorial staff to clarify implications and limits of the study.
About this research news
Author: Marianne Becker
Source: University of Southern Denmark
Contact: Marianne Becker, University of Southern Denmark
Image: Image credited to Neuroscience News
Original research: Open access. “N,N-dimethyltryptamine (DMT) is neither formed nor retained in serotonin terminals in the rat brain” by Mikael Palner, Elisabeth Kolesnik, Christina Baun, Sandra N. Poetzsch, and Paul Cumming. Neuropharmacology. DOI: 10.1016/j.neuropharm.2026.110874
Abstract (concise)
This study tested whether an endogenous pool of DMT accumulates in rat brain tissue and whether DMT can be stored in serotonin terminals. Researchers examined the effects of inhibiting monoamine oxidase and acidic metabolite transport, measured time courses for DMT and 3-IAA following administration, and assessed the impact of blocking SERT and VMAT2 on retention of exogenous DMT. Endogenous DMT remained below detection limits despite metabolic inhibition, and there was little evidence that exogenous DMT was retained in serotonergic terminals. The results indicate an absence of a detectable endogenous DMT pool in the rat brain regions and conditions studied.
Funding: Supported by the Swiss National Science Foundation (Grant Number 320030 204978).