A systematic review and meta-analysis of clinical trials on lavender for sleep disorders in older adults.

BACKGROUND: The present study aimed to gather existing findings related to the effect of lavender on improving sleep disorders in older adults. METHODS: In this systematic review, PubMed, Web of Science, Embase, and Scopus databases were searched using keywords ((lavender OR Lavandula) AND (sleep OR insomnia OR "sleep disturbance" OR "sleep quality" OR "sleep disorder") AND (elderly OR elder OR aging OR aging OR "older adult" OR geriatric OR geriatrics)) from their inception up to August 20, 2025. Only clinical trials evaluating the effect of lavender on aged patients (more than 60 years old) with sleep disorders were included. Then, data about drug formulation, dosage, duration of treatment, measurements, findings, and adverse events were recorded. A random-effects meta-analysis was used to calculate the pooled standardized mean differences (SMD) and their corresponding 95 % confidence intervals (CI). RESULTS: In this study, 84 articles were evaluated, and ten articles were selected for full review. In nine studies (90 %), lavender significantly improved sleep disorders. The most used scale among the articles was the Pittsburgh Sleep Quality Index (PSQI), which was used in seven studies (70 %). All the studies reported using lavender in the medicinal form of inhalation. The results of the meta-analysis indicated a significant improvement in the total score of sleep quality (SMD: -1.20, 95 % CI: -1.73, -0.68, I2: 87.5 %), with a more pronounced effect observed in studies that utilized the PSQI questionnaire. CONCLUSION: Based on preliminary evidence from this review, lavender may effectively treat sleep disorders, especially in the elderly. However, more research is required to fully understand its effectiveness and safety, especially with long-term use.