MAO-A is one of two forms of monoamine oxidase, a family of enzymes that break down serotonin, noradrenaline, dopamine and tyramine (Shulman et al., 2013). A 2018 review states that MAO-A is the primary route of metabolism for DMT, turning most of it into indole-3-acetic acid (Barker, 2018).
That speed is why DMT given by injection is short. A 2026 Basel study describes an elimination half-life of about 6 to 7 minutes (Erne et al., 2026). It is also why DMT swallowed alone does nothing: in a 2015 study of six people, no effect was felt and 97% of what was recovered in urine was the MAO product (Riba et al., 2015). Ayahuasca also contains β-carbolines that reversibly block MAO, which a 1984 analysis proposed lets DMT become active by mouth (McKenna, Towers and Abbott, 198490003-5)).
Because MAO also clears serotonin and tyramine, blocking it changes how the body handles many medicines, drugs and some foods; that is why prescription MAO-inhibitor antidepressants carry warnings (Shulman et al., 2013). Combining an MAO inhibitor with serotonin-acting drugs can be dangerous. This is not medical advice.
Sources
- Barker, 2018, Frontiers in Neuroscience: DMT metabolism and function
- Shulman et al., 2013, CNS Drugs: MAO inhibitors
- Riba et al., 2015, Drug Testing and Analysis: DMT metabolism in humans
- McKenna, Towers and Abbott, 1984, Journal of Ethnopharmacology: MAO inhibitors in ayahuasca
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