In line with this discrepancy, there is robust evidence for an increased CGRP release during stimulation of the trigeminal system [62] and during migraine attacks, measured in the venous outflow from the head [63–65] but also in saliva and tear fluid [66–68], whereas early reports about increases in salivary SP levels during migraine are inconsistent [69, 70]. Here, TFF2 is linked to migraine disorder.