Capturing in saliva real time emotions induced by a fragrance: an objective emotional assessment based on multiplex molecular biomarker profiles
This study introduces a non-invasive approach to objectively assess fragrance-induced emotions using multiplex salivary biomarker profiling. Traditional methods such as self-reports, physiological monitoring, or neuroimaging are often limited by subjectivity, invasiveness, or poor temporal resolution. Saliva offers a practical alternative, reflecting rapid neuroendocrine changes linked to emotional states. We analyzed four key salivary biomarkers: cortisol (stress, HPA-axis activity), alpha-amylase (sympathetic activation), dehydroepiandrosterone (resilience), and oxytocin (social bonding, emotional regulation) to capture multidimensional emotional responses. Two clinical studies (N=30, N=63) and one consumer study (N=80) exposed healthy volunteers to six fragrances, with saliva collected before, 5 minutes after, and 20 minutes after olfactory stimulation. Subjective ratings of happiness, relaxation, confidence, and dynamism were also obtained via questionnaires. Rigorous analytical validation accounted for reproducibility, circadian variation and sample stability. Biomarker patterns revealed fragrance-specific emotional profiles, with distinct subgroups of participants whose biomarker dynamics correlated with specific emotional states. Increased oxytocin and decreased cortisol consistently aligned with happiness and relaxation, whereas distinct biomarker combinations predicted confidence or dynamism. Classification and regression tree analysis demonstrated high sensitivity for detecting these profiles. Validation in an independent cohort (N=80) using an implicit association test confirmed concordance between molecular profiles and behavioral measures, underscoring the robustness of this method. These findings establish salivary biomarker profiling as a reliable tool for decoding real-time emotional responses. Beyond scientific insights into affective neuroscience, this approach holds translational potential in personalized fragrance design, sensory marketing, and therapeutic applications for stress-related disorders. Expanding the biomarker panel and integrating molecular data with neuroimaging or autonomic measures could further elucidate the interplay between central olfactory processing and peripheral physiology.