Salivary cortisol dynamics and their relationship with sleep and mental well-being in adults receiving a phospholipid-based Melissa officinalis supplement: a secondary analysis in a subpopulation

Background: Dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis, as indicated by altered salivary cortisol secretion, has been linked to poor sleep quality, mood disturbances, and emotional distress. In the principal clinical trial, 3 weeks of Melissa phospholipids’ supplementation was associated with significant improvements in sleep quality and mood outcomes. Objective: This study aimed to evaluate salivary cortisol dynamics in a subpopulation supplemented with Melissa officinalis extract formulated in phospholipids for 3 weeks. Design: This secondary analysis evaluated a predefined subgroup (n = 12) receiving 400 mg/day of Melissa phospholipids for 3 weeks. Salivary cortisol was collected at 3 timepoints at baseline (T0), week 1 (T1), and week 3 (T2), and quantified by high-sensitivity enzyme-linked immunosorbent assay (ELISA). Associations between cortisol levels and psychometric outcomes were also assessed. Results: Mean salivary cortisol levels decreased progressively over the 3-week supplementation period, with a significant main effect of time (P < 0.001). Significant correlations (P < 0.05) were also observed between psychometric domains, including PSQI, DASS-21 depression and stress, PANAS, WEMWBS, and WHOQoL-BREF scores, indicating consistent improvements in sleep quality, mood, and perceived well-being. Discussion and conclusions: This secondary analysis provides preliminary evidence that Melissa phospholipids supplementation, is associated with a significant modulation of HPA axis activity, characterized by a reduction in daily salivary cortisol levels, in adults with poor sleep quality and emotional distress.