Lavender: Research
Overview
This page provides a curated overview of selected peer-reviewed studies examining lavender, with emphasis on Silexan® (WS 1265), a standardized oral oil prepared from Lavandula angustifolia. The goal is to provide transparent access to research on relaxation, anxiety-associated sleep difficulties, mood, and daily functioning. The summaries describe published findings and their limitations as part of a clinician-led review of the scientific literature.
Important Context for Readers
Scientific studies examine outcomes in defined populations under specific research conditions. Results reported in individual studies may not apply to all individuals, and findings should not be interpreted as guaranteed outcomes. This page summarizes selected research examining defined populations under specific conditions. Many participants had persistent symptoms or diagnosed anxiety or depressive disorders; their results may not predict benefits for otherwise healthy people experiencing occasional stress. Findings for Silexan should not be generalized to lavender tea, aromatherapy, or other extracts. It is not intended to provide medical advice, diagnosis, or treatment recommendations. This page is provided for educational purposes and does not include product recommendations or affiliate links.
Summary of Evidence
The most consistent clinical evidence concerns short-term symptom changes with standardized oral Silexan. Average benefits over placebo were generally modest and varied across trials. Sleep findings mainly concern people with anxiety-associated sleep difficulties. Evidence for mood and daily functioning is developing.
The five trials in the principal anxiety meta-analysis were manufacturer-sponsored and conducted in Germany. The dedicated depression trial was conducted in Germany and Poland. Independent replication, more diverse populations, and longer follow-up would strengthen confidence. Short-term tolerability findings and small interaction studies do not establish safety for every person or medication combination.
Key Areas of Research
Mechanistic Research
1) Schuwald AM, Nöldner M, Wilmes T, et al. Lavender oil-potent anxiolytic properties via modulating voltage dependent calcium channels. PLoS One. 2013.
PMID: 23637742
DOI: https://doi.org/10.1371/journal.pone.0059998
Population: Rodent models, isolated nerve-cell preparations, and cultured cells; no human participants.
Design: Manufacturer-supported preclinical study combining animal behavioral testing, calcium imaging, and electrophysiological measurements to investigate Silexan’s effects on calcium channels.
Key findings:
• Silexan reduced calcium entry through several voltage-dependent calcium-channel types; effects in hippocampal nerve cells were mainly associated with N-type and P/Q-type channels
• Silexan also reduced anxiety-like behavior in mice, supporting a possible biological explanation for its effects
• These laboratory and animal findings do not establish the mechanism responsible for clinical benefits in humans or demonstrate equivalence to prescription medicines
Relaxation
Evidence strength: Moderate for short-term anxiety symptom reduction with the studied oral preparation; less certain for everyday stress in otherwise healthy adults.
The Hamilton Anxiety Rating Scale (HAM-A) is a clinician-rated questionnaire covering emotional and physical anxiety symptoms. Scores range from 0 to 56; lower scores indicate fewer symptoms. A group-average score difference does not guarantee a noticeable benefit for an individual.
2) Dold M, Bartova L, Volz HP, et al. Efficacy of Silexan in patients with anxiety disorders: a meta-analysis of randomized, placebo-controlled trials. Eur Arch Psychiatry Clin Neurosci. 2023.
PMID: 36717399
DOI: https://doi.org/10.1007/s00406-022-01547-w
Population: Adults with substantial anxiety symptoms across five trials; 1,213 randomized and 1,172 included in the efficacy analysis.
Design: Meta-analysis of Silexan 80 mg once daily versus placebo for 10 weeks.
Key findings:
• The average HAM-A improvement was approximately 2.9 points greater than placebo, a modest overall advantage
• About 52% versus 39% had their symptom score fall by at least half: approximately 13 additional people per 100 reaching that study-defined response
• Effect sizes varied substantially; one of the five trials did not demonstrate a statistically significant advantage on the main anxiety score
3) Donelli D, Antonelli M, Bellinazzi C, et al. Effects of lavender on anxiety: A systematic review and meta-analysis. Phytomedicine. 2019.
PMID: 31655395
DOI: https://doi.org/10.1016/j.phymed.2019.153099
Population: Participants in varied clinical and anxiety-provoking settings. The quantitative analysis included 37 randomized trials with 3,964 participants across different lavender preparations and routes.
Design: Systematic review of oral, inhaled, and other lavender interventions; searches covered studies available through November 2018.
Key findings:
• Oral Silexan studies generally favored the studied preparation for anxiety symptom scores
• Most included trials had high overall risk of bias; inhalation and massage findings were especially hard to interpret.
• The review reported no funding. It provides a broader appraisal of lavender research, while emphasizing that preparations and routes are not interchangeable
4) Kasper S, Gastpar M, Müller WE, et al. Lavender oil preparation Silexan is effective in generalized anxiety disorder—a randomized, double-blind comparison to placebo and paroxetine. Int J Neuropsychopharmacol. 2014.
PMID: 24456909
DOI: https://doi.org/10.1017/S1461145714000017
Population: 539 adults with generalized anxiety disorder, a condition involving persistent, difficult-to-control worry.
Design: Ten-week randomized trial comparing Silexan 80 mg daily, Silexan 160 mg daily, paroxetine 20 mg daily, and placebo. Paroxetine is a prescription antidepressant also used for anxiety disorders.
Key findings:
• Both Silexan doses produced greater average HAM-A improvement than placebo
• Paroxetine did not clearly outperform placebo in the main analysis, although results differed when only available follow-up measurements were analyzed
• The study supports benefit for the tested preparation but does not establish equivalence to paroxetine or justify replacing prescribed treatment
5) Woelk H, Schläfke S. A multi-center, double-blind, randomised study of the lavender oil preparation Silexan in comparison to lorazepam for generalized anxiety disorder. Phytomedicine. 2010.
PMID: 19962288
DOI: https://doi.org/10.1016/j.phymed.2009.10.006
Population: 77 adults with generalized anxiety disorder.
Design: Six-week randomized comparison of Silexan 80 mg daily and lorazepam 0.5 mg daily, a prescription benzodiazepine used for anxiety. There was no placebo group.
Key findings:
• Average HAM-A reductions were similar: approximately 11.3 points with Silexan and 11.6 points with lorazepam
• These are changes from the start of the study, not effects measured against placebo
• The small sample, short duration, and low lorazepam dose limit comparative conclusions. Similar group averages do not establish that one can replace the other in clinical care
6) Kasper S, Eckert A. Silexan in anxiety, depression, and related disorders: pharmacological background and clinical data. Eur Arch Psychiatry Clin Neurosci. 2025;275:1621–1635. Published online October 25, 2024.
PMID: 39453446
DOI: https://doi.org/10.1007/s00406-024-01923-8
Population: Published clinical populations with anxiety, related sleep complaints, and depressive symptoms, alongside experimental research.
Design: Narrative review of six controlled anxiety trials, a dedicated depression trial, and supporting pharmacological and observational studies.
Key findings:
• Provides an overview of clinical outcomes, proposed mechanisms, and tolerability, including burping and digestive complaints
• Mechanistic findings help frame research questions but do not independently establish clinical benefit
• This is a synthesis of existing studies, not an additional trial. Observations in special populations, including post-COVID settings, remain less conclusive
Sleep Support
Evidence Strength: Low to moderate for anxiety-associated sleep difficulties; insufficient to establish efficacy for chronic insomnia occurring independently of anxiety.
The Pittsburgh Sleep Quality Index (PSQI) is a self-reported questionnaire about sleep quality and related difficulties. Scores range from 0 to 21; lower scores indicate fewer problems. It is not an objective sleep recording, and score changes cannot be converted directly into extra hours slept.
7) Kasper S, Gastpar M, Müller WE, et al. Silexan, an orally administered Lavandula oil preparation, is effective in the treatment of ‘subsyndromal’ anxiety disorder: a randomized, double-blind, placebo controlled trial. Int Clin Psychopharmacol. 2010.
PMID: 20512042
DOI: https://doi.org/10.1097/YIC.0b013e32833b3242
Population: 221 adults randomized with substantial anxiety symptoms and disturbed sleep. “Subsyndromal” means that symptoms did not meet the full criteria for a particular anxiety disorder; it does not necessarily mean mild everyday stress.
Design: Silexan 80 mg once daily versus placebo for 10 weeks, with anxiety and sleep questionnaire scores as primary outcomes.
Key findings:
• Average PSQI scores improved by 5.5 points with Silexan versus 3.8 with placebo, a between-group difference of about 1.7 points
• Anxiety symptoms also improved more with Silexan
• The sleep result suggests a modest questionnaire-level advantage. Its importance to an individual patient is less certain, particularly outside this selected population
8) Kasper S, Anghelescu I, Dienel A. Efficacy of orally administered Silexan in patients with anxiety-related restlessness and disturbed sleep—A randomized, placebo-controlled trial. Eur Neuropsychopharmacol. 2015.
PMID: 26293583
DOI: https://doi.org/10.1016/j.euroneuro.2015.07.024
Population: 170 adults with restlessness, substantial anxiety symptoms, and disturbed sleep.
Design: Silexan 80 mg once daily versus placebo for 10 weeks, using anxiety ratings and sleep questionnaires.
Key findings:
• HAM-A improvement was approximately 2.7 points greater than placebo
• Questionnaire outcomes generally favored Silexan, but the clearest reported finding was reduced anxiety symptoms
• Sleep was evaluated in an anxious, restless population. This trial does not establish an immediate sedative effect or efficacy for an independent chronic insomnia
9) Seifritz E, Schläfke S, Holsboer-Trachsler E. Beneficial effects of Silexan on sleep are mediated by its anxiolytic effect. J Psychiatr Res. 2019.
PMID: 31121394
DOI: https://doi.org/10.1016/j.jpsychires.2019.04.013
Population: 212 participants included in the efficacy analysis of the 2010 trial summarized in Reference 7.
Design: Secondary statistical analysis examining whether sleep changes were associated with improvements in anxiety after 10 weeks of Silexan 80 mg daily or placebo.
Key findings:
• The model suggested that most of the observed sleep improvement was explained by improvement in anxiety, with little estimated direct effect on sleep
• This supports the interpretation that feeling calmer may improve rest
• The analysis does not prove the biological pathway, demonstrate an immediate sleep-inducing effect, or add a new independent group of participants
Other Support (Mood and Daily Functioning)
Evidence strength: Low to moderate and developing, based on pooled secondary outcomes and one dedicated placebo-controlled depression trial.
The studies below concern clinically significant symptoms. They do not establish a general mood-enhancing effect in healthy adults. Daily-functioning measures examine how symptoms interfere with work, relationships, and home responsibilities.
10) Bartova L, Dold M, Volz HP, et al. Beneficial effects of Silexan on co-occurring depressive symptoms in patients with subthreshold anxiety and anxiety disorders: randomized, placebo-controlled trials revisited. Eur Arch Psychiatry Clin Neurosci. 2023.
PMID: 35262795
DOI: https://doi.org/10.1007/s00406-022-01390-z
Population: The same five anxiety-trial populations included in Reference 2, with 1,172 participants analyzed for efficacy.
Design: Meta-analysis of mood outcomes during 10 weeks of Silexan 80 mg daily or placebo. All trials assessed depressed mood within the anxiety scale; three also used dedicated depression questionnaires.
Key findings:
• Small average improvements in depressive symptoms favored Silexan
• Greater improvements were reported among participants with more depressive symptoms initially
• The analysis could not establish whether mood improved directly or through reduced anxiety. It reuses existing anxiety-trial data and is not independent confirmation in a new depression population
11) Kasper S, Volz HP, Möller HJ, et al. Lavender oil preparation Silexan is effective in mild-to-moderate major depression: a randomized, placebo- and reference-controlled trial. Eur Arch Psychiatry Clin Neurosci. 2025.
PMID: 38558147
DOI: https://doi.org/10.1007/s00406-024-01783-2
Population: Adults with mild-to-moderate major depression; 500 randomized and 498 treated and analyzed.
Design: Eight-week trial of Silexan 80 mg daily, sertraline 50 mg daily, or placebo. Sertraline is a prescription antidepressant.
Key findings:
• Silexan’s advantage over placebo was about 2.2 points on the Montgomery–Åsberg Depression Rating Scale, a clinician-rated measure ranging from 0 to 60; lower scores indicate fewer symptoms
• The daily-functioning advantage over placebo was about 2.4 points on the Sheehan Disability Scale, a 0–30 self-rating of disruption to work, social life, and home responsibilities. Lower scores indicate less disruption
• The symptom advantage was modest. The functioning result may matter to patients, but was a secondary outcome requiring confirmation
• Silexan and sertraline each outperformed placebo on the main symptom measure; the trial was not designed or powered to compare them with each other, so it does not establish equivalence
Supporting Safety and Medication-
Interaction Research
Evidence strength: Limited but reassuring for the specific combinations tested.
Small studies in healthy volunteers can identify some interactions, but cannot exclude uncommon problems or establish safety with every medication.
12) Doroshyenko O, Rokitta D, Zadoyan G, et al. Drug cocktail interaction study on the effect of the orally administered lavender oil preparation Silexan on cytochrome P450 enzymes in healthy volunteers. Drug Metab Dispos. 2013.
PMID: 23401474
DOI: https://doi.org/10.1124/dmd.112.050203
Population: 16 healthy volunteers who completed the study.
Design: Randomized crossover study, in which each participant received Silexan 160 mg daily and placebo during separate 11-day periods. Test medicines assessed cytochrome P450 (CYP) enzymes, proteins that process many medications.
Key findings:
• Investigators found no clinically important overall effect on the tested drug-processing pathways
• For one enzyme, CYP2C19, the uncertainty range for an omeprazole exposure measure exceeded the study’s predefined limits. The authors attributed this to variability; other related measures were reassuring
• These findings support a limited interaction assessment, not a blanket claim of “no drug interactions”
13) Heger-Mahn D, Pabst G, Dienel A, et al. No interacting influence of lavender oil preparation Silexan on oral contraception using an ethinyl estradiol/levonorgestrel combination. Drugs R D. 2014.
PMID: 25319228
DOI: https://doi.org/10.1007/s40268-014-0065-5
Population: 24 healthy adult women taking a combined oral contraceptive containing ethinyl estradiol 30 micrograms and levonorgestrel 150 micrograms.
Design: Randomized crossover study of Silexan 160 mg daily or placebo during two consecutive 28-day cycles, measuring hormone exposure and indicators of ovarian activity.
Key findings:
• No meaningful change in overall exposure to the two contraceptive hormones was detected
• The measured hormonal and ovarian indicators did not suggest impaired contraceptive activity
• The study was not designed to compare pregnancy rates and does not establish the absence of interactions with every hormonal contraceptive
Educational Notice
These summaries are provided for educational purposes to review published scientific literature and should not be interpreted as medical advice, diagnosis, or treatment recommendations. Readers should consult qualified healthcare professionals for personal medical decisions.
FDA Disclaimer
These statements have not been evaluated by the U.S. Food and Drug Administration. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease.
FTC Affiliate Disclosure
Some pages on this website may contain affiliate links to products. If readers choose to purchase through those links, the site may receive a commission. Affiliate relationships do not influence the selection or discussion of scientific studies summarized on this reference page.