The Science Behind Vanilla’s Calming Effect on the Nervous System

It’s one of the most beloved scents in the world—soft, warm, and instantly familiar. But beyond its comforting aroma, vanilla may have a measurable calming effect on the body’s startle reflex, according to a compelling study published in Psychophysiology.

In the study, researchers set out to examine how different odors influence the body’s automatic response to sudden stimuli. Known as the startle reflex, this lightning-fast reaction is part of the body’s built-in survival system—triggered when we hear a loud noise or sense an immediate threat.

Participants in the study were exposed to two distinct odors: hydrogen sulfide (H₂S), which smells unpleasantly like rotten eggs, and vanillin, the primary aromatic compound found in vanilla (Vanilla planifolia). During odor exposure, participants were subjected to brief, unexpected noises while researchers measured their physical startle response.

The results were striking: while the unpleasant scent of H₂S heightened the startle reflex, the scent of vanillin reduced it. Both odors were rated equally intense, meaning the calming effect of vanilla wasn’t due to it being weaker—it was directly linked to its positive emotional quality.

This finding suggests that vanilla’s scent has the ability to modulate our stress response at a neurological level, gently reducing the brain’s and body’s readiness to react. In essence, vanilla doesn’t just smell comforting—it can actually help soothe the nervous system in moments of high alert.

Source: Psychophysiology