Digital interventions for promoting relaxation are increasingly popular, yet few combine multiple sensory modalities. This study evaluated the effectiveness of a fully digital relaxation program combining hypnotherapy with aromatherapy and explored whether the scent can induce a conditioned relaxation effect.

In this four-arm randomized controlled trial (N = 504), participants were assigned to one of four groups for a 4-week intervention: (a) combined (hypnotherapy + aromatherapy), (b) hypnotherapy-only, (c) aromatherapy-only, or (d) control (minimal intervention pause). Sessions were self-guided and delivered online every 2 days. The primary outcome was subjective calmness, assessed via the calmness–restlessness subscale of the Multidimensional Mood Questionnaire. Secondary outcomes included perceived stress (PSS-10) and well-being (WHO-5). A fifth week with aromatherapy-only exposure was conducted in the combined and aromatherapy-only groups to test for conditioning.

At post-intervention, both hypnotherapy-involved groups reported significant greater calmness than controls. The combined group showed a mean difference of β = 2.08 (95% CI: 0.50–3.65, p = 0.010, d = 0.38), while the hypnotherapy-only group showed β = 1.80 (95% CI: 0.24–3.37, p = 0.024, d = 0.33). Both effects were consistent across intention-to-treat and per-protocol analyses. Within-group improvements in calmness were also observed across all groups. No significant differences emerged from the conditioning test in week 5.

Digital hypnotherapy improved relaxation, with modest added benefit from aromatherapy. The results support the use of multisensory digital tools to enhance subjective calmness. However, no evidence for conditioned effects of the scent was observed under the current conditions.