I assume you’re talking about the unsubstituded tryptamine molecule, basically serotonin without the oxygen atom. I actually tried to find the answer to this myself and created a thread about it several years ago but unfortunately, no one was really sure. however, the main theory is that it would probably act as a serotonin releasing agent and non-selective serotonin receptor agonist. this means that potentially psychoactive doses would mainly produce severe negative effects, including peripheral vasoconstriction and high heart rate as well as hyperthermia(High body temperature) along with extreme anxiety, mental confusion and possible hallucinations. these are the symptoms of serotonin syndrome. it is very likely that tryptamine, being a trace Amine is a powerful endogenous modulator of the serotonin system, in the same way that The endogenous trace amine Phenylethylamine modulates the dopamine system.