INMT is an enzyme that moves methyl groups onto small molecules. In the textbook DMT pathway it does this twice, turning tryptamine into N-methyltryptamine and then into DMT (Glynos et al., 2023). In 1961 Julius Axelrod reported an enzyme in rabbit lung that methylates serotonin and tryptamine into bufotenine and DMT (Axelrod, 1961).
It is not a DMT specialist; it works on a range of the body’s own amines and other small molecules (Glynos et al., 2023). A 2019 study found INMT messenger RNA in rat and human cortex, pineal gland and choroid plexus (Dean et al., 2019), though messenger RNA is not the same as enzyme activity.
Knockout experiments unsettled the story. Rats with INMT deleted in 2023 kept their tryptamine-methylating activity (Glynos et al., 2023), and INMT-knockout mice in 2025 showed no obvious drop in their own psychedelic tryptamines (Hatzipantelis et al., 2025). In rodents something else seems to do the job, and no one knows what. Nobody has tested the question in human cells.
Sources
- Axelrod, 1961, Science: enzymatic formation of psychotomimetic metabolites
- Glynos et al., 2023, Scientific Reports: INMT knockout rats
- Dean et al., 2019, Scientific Reports: DMT and INMT in mammalian brain
- Hatzipantelis et al., 2025, ACS Chemical Neuroscience: INMT knockout mice
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