Big effect
Lavender inhalation lowered a standard sleep-quality score by 1.2 standard deviations in older adults — but all six trials were unblinded, so the placebo effect could not be ruled out.
The effect is unusually large for a sleep intervention in a meta-analysis, but because every study tested lavender against nothing rather than a placebo (e.g., a sham scent), the result may partly reflect expectation and ritual, not the herb itself — moderate overall evidence from six consistent trials.
In older adults with sleep problems, inhaling lavender led to a substantial improvement in subjective sleep quality, measured by the Pittsburgh Sleep Quality Index. However, none of the trials used a blinded placebo, meaning participants knew they were getting an active treatment, which can inflate perceived benefits.
Where this fits in the evidence
Pillser has synthesized 10 studies on Lavender for Improved Sleep Quality — overall evidence strength: High.
Across 10 studies, all 10 reported beneficial effects of lavender on sleep quality, with 10 reaching statistical significance. The predominant effect size was moderate, with effect sizes ranging from small to large. Effects were observed primarily with inhalation aromatherapy (the most common form) and oral dosing at 500 mg/day in one study, with a median study duration of 28 days; studies included clinical populations such as adults with hypertension, cancer patients, and postmenopausal women.
The study
- Meta-Analysis
- 2025-11
- Experimental gerontology
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