Endogenous DMT means DMT made inside the body. The textbook pathway runs from the amino acid tryptophan to tryptamine, then through two methylation steps long credited to an enzyme called INMT (Barker, 2018). Careful mass-spectrometry studies have found DMT in human blood, urine and spinal fluid. No one has measured it in a living human brain.
The search began in the 1950s, partly because of the “transmethylation hypothesis”, the idea that conditions such as schizophrenia might involve the body making its own hallucinogens. That premise remains unproven (Barker, 2022). A 2012 review of 69 studies from 1955 to 2010 examined how well each one actually showed DMT was present (Barker et al., 2012).
The amounts found in people are small. A 2019 paper notes that human body-fluid studies report DMT only in trace amounts, “calling into question any physiological role”. The same team measured DMT in living rat brain and found INMT messenger RNA in human autopsy brain tissue (Dean et al., 2019). Later knockout studies found that rats lacking INMT still methylated tryptamines (Glynos et al., 2023), which leaves open how DMT is made at all. Popular claims that the brain floods with DMT at birth, in dreams or at death go well beyond this evidence.
Sources
- Barker, 2018, Frontiers in Neuroscience: DMT, an endogenous hallucinogen
- Barker, McIlhenny and Strassman, 2012, Drug Testing and Analysis: critical review 1955–2010
- Dean et al., 2019, Scientific Reports: DMT in mammalian brain
- Glynos et al., 2023, Scientific Reports: INMT not essential in rats
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