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 8 studies on Lavender for Improved Sleep Quality — overall evidence strength: High.
Across 8 studies, all 8 reported beneficial effects of lavender on sleep quality, with effect sizes ranging from small to large and predominantly moderate to large. The most studied populations include adults with hypertension, patients with hematological malignancies undergoing chemotherapy, postmenopausal women, and older adults with sleep disorders, with common interventions involving inhaled lavender essential oil over 5–7 days.
The study
- Meta-Analysis
- 2025-11
- Experimental gerontology
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