Dietary Supplementation with an Extract of Aloysia citrodora (Lemon verbena) Improves Sleep Quality in Healthy Subjects: A Randomized Double-Blind Controlled Study

Abstract

A single-center, randomized, double-blind, placebo-controlled clinical trial with two arms was conducted in 71 healthy subjects suffering from sleep disturbances, which were treated with a dietary supplement based on an extract of Aloysia citrodora (or Lippia citriodora, lemon verbena) (n = 33) for 90 days. Subjects in the placebo group (n = 38) received capsules of microcrystalline and maltodextrin with the same organoleptic properties. Between-group significant differences in favor of the experimental group were found in the visual analogue scale (VAS) score rating sleep quality; overall score, sleep latency and sleep efficiency of the Pittsburg Sleep Quality Index (PSQI); and sleep latency, sleep efficiency, wakefulness after sleep onset and duration of awakening assessed by actigraphy. Plasma nocturnal melatonin levels also increased significantly in the experimental group. Changes in anthropometric parameters and physical activity levels were not found. This study shows that the administration of a dietary supplement comprised lemon verbena administered for 3 months was associated with a significant improvement of sleep quality as compared with placebo in a population of healthy subjects with sleep problems. Improvements were also apparent at the mid-study visit after 45 days of supplementation.