Subjective assessment of the effects of an herbal supplement containing lavender essential oil on sleep quality: A randomized, double-blind, placebo-controlled crossover study

Sleep disorders are associated with an elevated risk of developing various diseases. Herbal supplementation has been shown to alleviate sleep disorders such as insomnia. Here, the effect on sleep quality of an herbal supplement was evaluated subjectively. The supplement primarily contained lavender essential oil, as well as L-theanine and extracts of lemon balm, passion flower, and chamomile. Fifty-one healthy adults with self-reported symptoms of insomnia, divided into placebo and treatment groups, completed a 6-week crossover study (1-week washout, 2-week intervention, 1-week washout, and 2-week intervention, sequentially). Participants were asked to fill out the Leeds Sleep Evaluation Questionnaire (LSEQ) survey weekly and keep a sleep diary daily, which were used to assess their sleep quality. Compared to the placebo group, the active group (participants who received the supplement) showed significant improvements in overall LSEQ scores (p < 0.01) and several individual LSEQ measures. No significant differences in data from the sleep diaries were observed. Age, body mass index, gender, and ethnicity did not significantly interact with any dependent variable. No serious adverse event was reported. The lavender oil containing supplement was effective in improving several subjective sleep parameters in participants with mild to moderate insomnia.