A Randomised Double-blind Placebo-controlled Trial on Encapsulated Lemon Balm Efficacy and Tolerance on Sleep Quality Changes, and Mood and Wellbeing Effects Using Objective and Subjective Measures

A randomised, double-blind, placebo-controlled, parallel-design study assessing the effect of a 4-week intervention of lemon balm extract (or matched placebo) in young to middle-age adults with mild sleep problems. A total of 108 participants will be randomly assigned to either 300 mg lemon balm extract or a matched placebo capsule consumed nightly before retiring to bed. The severity of sleep problems, depression, anxiety, perceived stress, quality of life and well-being will be measured at baseline and after 4 weeks of daily consumption. In addition, we will assess changes in microbiota and saliva neurohormone profiles at baseline and after 4 weeks of treatment.

Entry to the study to determine eligibility involves a sleep quality questionnaire (PSQI) score of 5 and above. The study comprises of a familiarisation visit and then two test days at the Nutritional Psychology Unit based at the University of Reading where primary sleep (PSQI), and exploratory measures of sleep (ISI, LSEQ) and mood (PANAS, Vivascentz(TM), FFS, PSS, DASS-21) tests will be completed. The screening visit will further assess habitual diet (Epic-Norfolk FFQ), and general health and lifestyle patterns to confirm eligibility. Participants will then continuously wear an wrist-secured actiwatch whilst recording a daily sleep diary to estimate sleep changes over the 4-week period. In addition, some further exploratory tests will be completed by participants from home 24h before baseline and 24h before post-intervention (saliva, stool, PANAS-X).