Telepathine is an old name for harmine, a beta-carboline found in plants like Banisteriopsis caapi. The term came from early reports on ayahuasca and does not imply real telepathy. Pharmacologically, harmine is a reversible, selective MAO-A inhibitor, and it is an active compound in its own right.
With DMT, harmine’s MAO-A inhibition allows oral activity and makes the experience longer and different compared to smoked or insufflated DMT. This is the core of ayahuasca-type effects.
With psilocybin or psilocin, harmine is not required for oral activity. It may intensify or prolong effects for some people, but outcomes can be more nauseating, emotional, and less predictable. Evidence in humans for this combination is limited.
Because harmine inhibits MAO-A, it can interact with serotonergic or stimulant substances such as SSRIs, SNRIs, MDMA, amphetamines, tramadol, dextromethorphan, and linezolid. For a concise overview of potential interactions and contraindications, see this article: caapi interactions and contraindications. When unsure, avoid mixing.