Lavender and sleep: A systematic review of the evidence

Introduction and aim: Poor quality sleep affects a large proportion of the UK population. Surveys of health-seeking behaviour suggest a preference for self-care remedies while essential oil aroma inhalation is a popular aromatherapy application. Anecdotally, lavender oil has sedative or sleep enhancing properties and is believed to cause few side effects. The aim of this review was to systematically search the literature and examine the evidence on lavender (Lavandula sp.) aroma inhalation (as a possible self-care intervention) to improve sleep architecture (initiation, maintenance and quality). Methods: Major medical databases including AMED, BNI, Cochrane CENTRAL, EMBASE, MEDLINE, PsycINFO and PubMed, specialist complementary and alternative medicine databases and trials registers were searched systematically up to April 2012. All controlled human trials in which lavender oil aroma inhalation was used as single intervention were retrieved. Only those published in English were appraised in detail. Results: No previous systematic review focusing on lavender in sleep was identified. Eight eligible studies were found of which 4 were randomised controlled trials, 1 was counterbalanced and 3 were non-randomised controlled trials. Most studies had small samples and methodological limitations. Results suggested lavender oil may be of small to moderate benefit. Discussion/conclusion: Early results appear promising but they should be viewed with caution. More scientifically rigorous and adequately powered trials are needed to investigate the true effect of lavender oil aroma inhalation on sleep. Due to the clinical significance of waking function as influenced by sleep, the use of wake outcome measures should also be considered. (C) 2012 Elsevier GmbH. All rights reserved.