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 9 studies on Lavender for Improved Sleep Quality — overall evidence strength: High.
Across 9 studies, all reported beneficial effects of lavender on sleep quality, with predominantly moderate effect sizes. The evidence includes two meta-analyses and multiple randomized controlled trials, primarily in clinical populations such as adults with hypertension, cancer patients undergoing chemotherapy, and postmenopausal women. Median study duration was 18 days, with doses varying widely (e.g., 500 mg/day orally, 15-minute inhalation sessions daily) and no single form or dose consistently used across studies.
The study
- Meta-Analysis
- 2025-11
- Experimental gerontology
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