Topical peppermint contains menthol, which acts as a counterirritant and activates TRPM8 cold receptors, causing local vasodilation and sensory nerve stimulation. When applied to the forehead or temples, it can provide a cooling sensation that may help interrupt pain signaling and reduce muscle tension associated with cluster headaches. The analgesic and vasodilatory properties of menthol contribute to its potential symptomatic relief mechanism.