One of the principle, bioactive alkaloids of Evodia rutaecarpa. Like capsaicin, evodiamine is a vanilloid receptor agonist, with thermogenic and (potential) anti-obesity effects. Evodiamine may also have therapeutic potential, due to its anti-tumor and analgesic effects.
Evodiamine is often added to fat burners (purified or as a standardized extract of Evodia) to promote thermogenesis. It’s alleged to invoke a “shivering” response, although this is strictly anecdotal.