Lavender

What Is Lavender?

Lavender is one of the most famous herbs known to man. It’s cultivated on a massive scale throughout Europe and North America and is a popular flavoring and aromatic agent for household products.

Medicinally lavender is best known for its ability to promote sleep. It’s often sold as aromatherapy, in salves and creams, and incense for this purpose.

Lavender essential oil can be used as a topical agent for insect bites, rashes, and infection.

What Is Lavender Used For?

Lavender is mainly used in topical applications for rashes, skin irritations, mild infections, sunburn, and insect bites. Internally it’s mainly used for anxiety-related conditions, GIT inflammation and discomfort, and insomnia.

Its best-supported use by a wide margin is anxiety — and specifically as a standardised oral essential-oil capsule (Silexan), not as the tea or the tincture (see the research section below). Sleep and low mood improve mostly as a knock-on effect of reduced anxiety rather than as primary effects. The topical, analgesic, antispasmodic and antimicrobial uses are traditional and mechanistically plausible but rest on animal, in-vitro or small aromatherapy trials, so they are best read as traditional uses rather than established ones.

Botany

English lavender is a semi-woody, evergreen-in-warm-climates perennial subshrub in the mint family (Lamiaceae) — the same aromatic family as sage, thyme, oregano, basil and holy basil — typically growing 1.5–3 ft tall with narrow, gray-green, fragrant leaves on square stems and purple flowers in terminal spikes from late spring into summer ^{34Reference 34Missouri Botanical Garden Plant Finder —https://www.missouribotanicalgarden.org/plantfinder/PlantFinderDetails.aspx?taxonid=281393View study →}. The genus Lavandula holds roughly 47 species, most of them perennials or small shrubs; besides English lavender, other lavenders used medicinally include French lavender (L. stoechas) and Spanish lavender (L. dentata), though taxonomists dispute exactly which common name maps to which species ^{34Reference 34Missouri Botanical Garden Plant Finder —https://www.missouribotanicalgarden.org/plantfinder/PlantFinderDetails.aspx?taxonid=281393View study →}.

Sources

34. Missouri Botanical Garden Plant Finder — Lavandula angustifolia. https://www.missouribotanicalgarden.org/plantfinder/PlantFinderDetails.aspx?taxonid=281393

Distribution

Native primarily to the Mediterranean region of southern Europe ^{34Reference 34Missouri Botanical Garden Plant Finder —https://www.missouribotanicalgarden.org/plantfinder/PlantFinderDetails.aspx?taxonid=281393View study →}. Despite the common name, English lavender is not native to England — it was so named for growing well in the English climate. It is a long-cultivated garden, culinary and perfumery herb worldwide, with no weed, invasive, or conservation-status concern documented.

Sources

34. Missouri Botanical Garden Plant Finder — Lavandula angustifolia. https://www.missouribotanicalgarden.org/plantfinder/PlantFinderDetails.aspx?taxonid=281393

Growing Conditions

• Life cycle: semi-woody perennial subshrub, hardy USDA zones 5–8 ^{34Reference 34Missouri Botanical Garden Plant Finder —https://www.missouribotanicalgarden.org/plantfinder/PlantFinderDetails.aspx?taxonid=281393View study →}.
• Light: full sun.
• Water: dry to medium; well-drained, alkaline soil is essential — root rot is the main failure mode in wet conditions.
• Habit: benefits from a spring shape-prune and a hard cutback (to ~8”) every 3 years to control size and promote vigorous new growth.
• Full cultivation details live on the companion farm-wiki grow guide for Lavandula angustifolia (link to be added once that project’s public URL is confirmed).

Sources

34. Missouri Botanical Garden Plant Finder — Lavandula angustifolia. https://www.missouribotanicalgarden.org/plantfinder/PlantFinderDetails.aspx?taxonid=281393

Phytochemistry

True lavender is, above all, a linalool/linalyl-acetate oil: these two monoterpenes together make up roughly 60–80% of the essential oil and carry most of the calming and antispasmodic activity ^{32,33Reference 32ISO 3515:2002 · 2002Oil of lavender (Lavandula angustifolia Mill.)Reference 33Cavanagh et al. · 2002ReviewBiological activities of lavender essential oil — review}. What sets Lavandula angustifolia apart from its coarser relatives (spike lavender and lavandin) is what it lacks — good lavender oil stays low in camphor (≤0.5%) and 1,8-cineole, so elevated levels of either flag adulteration or a different species ^{32Reference 32ISO 3515:2002 · 2002Oil of lavender (Lavandula angustifolia Mill.)}. Supporting volatiles include terpinen-4-ol, the ocimenes, lavandulyl acetate and a little caryophyllene ^{32,33Reference 32ISO 3515:2002 · 2002Oil of lavender (Lavandula angustifolia Mill.)Reference 33Cavanagh et al. · 2002ReviewBiological activities of lavender essential oil — review}.

Constituent Summary

Figures are the ISO 3515 composition limits for Lavandula angustifolia oil (share of essential oil); natural samples vary widely. † marks the compounds whose levels distinguish true lavender from spike lavender and lavandin — in true lavender they should stay low ^{32,33Reference 32ISO 3515:2002 · 2002Oil of lavender (Lavandula angustifolia Mill.)Reference 33Cavanagh et al. · 2002ReviewBiological activities of lavender essential oil — review}.

Pharmacology & Research

Lavender is one of the few medicinal plants with genuine randomised-controlled-trial evidence behind it — but almost all of it belongs to a single preparation. The oral lavender-oil softgel Silexan (a standardised steam-distilled Lavandula angustifolia essential oil, 80–160 mg/day) has been tested in more than a dozen placebo-controlled anxiety trials and pooled into meta-analyses, putting anxiety in a tier most herbs never reach ^{1,2,3,4,5,6,7Reference 1Kasper et al. · 2010RCTSilexan, an orally administered Lavandula oil preparation, is effective in the treatment of ‘subsyndromal’ anxiety disorder — randomized, double-blind, placebo-controlled trialView study →Reference 2Kasper et al. · 2014RCTLavender oil preparation Silexan is effective in generalized anxiety disorder — a randomized, double-blind comparison to placebo and paroxetineView study →Reference 3Woelk et al. · 2010RCTA multi-center, double-blind, randomised study of the Lavender oil preparation Silexan in comparison to Lorazepam for generalized anxiety disorder — randomized controlled trialView study →Reference 4Kasper et al. · 2016RCTEfficacy of Silexan in mixed anxiety–depression — a randomized, placebo-controlled trialView study →Reference 5Kasper et al. · 2017RCTSilexan in generalized anxiety disorder: investigation of the therapeutic dosage range in a pooled data set — randomized controlled trialView study →Reference 6Yap et al. · 2019Meta-analysisEfficacy and safety of lavender essential oil (Silexan) capsules among patients suffering from anxiety disorders — network meta-analysisView study →Reference 7Dold et al. · 2023Meta-analysisEfficacy of Silexan in patients with anxiety disorders — a meta-analysis of randomized, placebo-controlled trialsView study →}. Everything else — sleep, low mood, pain, spasm, microbial and neuroprotective effects — rests on inhaled aromatherapy trials of mixed quality or on animal and in-vitro work with the isolated monoterpenes linalool and linalyl acetate ^{11,12,13,14,15,16,17,18,19,20,21,22Reference 11Seifritz et al. · 2022ReviewEffect of the anxiolytic drug silexan on sleep — a narrative reviewView study →Reference 12Shen et al. · 2026Meta-analysisThe sleep-enhancing effect of lavender essential oil in adults — a systematic review and meta-analysisView study →Reference 13Xu et al. · 2024Meta-analysisEffects of aromatherapy on sleep quality in older adults — a meta-analysisView study →Reference 14Baldinger et al. · 2014RCTEffects of Silexan on the serotonin-1A receptor and microstructure of the human brain — a randomized, placebo-controlled PET studyView study →Reference 15López et al. · 2017In vitroExploring pharmacological mechanisms of lavender (Lavandula angustifolia) essential oil on central nervous system targets — in vitroView study →Reference 16Chioca et al. · 2013AnimalAnxiolytic-like effect of lavender essential oil inhalation in mice: participation of serotonergic but not GABA-A/benzodiazepine neurotransmission — animal modelView study →Reference 17Peana et al. · 2002AnimalAnti-inflammatory activity of linalool and linalyl acetate constituents of essential oils — rat modelView study →Reference 18Peana et al. · 2006AnimalInvolvement of adenosine A1 and A2A receptors in (−)-linalool-induced antinociception — animal modelView study →Reference 19Peana et al. · 2004AnimalEffects of (−)-linalool in the acute hyperalgesia induced by carrageenan, L-glutamate and prostaglandin E2 — rat modelView study →Reference 20Koto et al. · 2006In vitroLinalyl acetate as a major ingredient of lavender essential oil relaxes the rabbit/rat smooth muscle — in vitro/animal modelView study →Reference 21Lis-Balchin et al. · 1999In vitroStudies on the mode of action of the essential oil of lavender (Lavandula angustifolia) — in vitro smooth-muscle studyView study →Reference 22Xu et al. · 2016AnimalProtective effect of lavender oil on scopolamine-induced cognitive deficits in mice — animal modelView study →}. The central caveat runs through the whole page: the clinical data are for a concentrated oral or inhaled essential oil, not for the 1:2 liquid extract or the dried-flower tea, and the results do not automatically transfer between those forms.

0. Evidence by indication

Support is an experimental score I’m building — a composite weighted by study type (human > animal > in vitro > review) and study volume. It’s a beta: a fast way to rank strength of evidence at a glance, not a validated metric, and I’ll keep honing the formula over time. Each indication name links down to its write-up.

Indication	Support	Rests on
Anxiety	█████████░ 88%	Multiple RCTs + meta-analysis of oral Silexan; strong and consistent — but one standardised capsule, not the tea or tincture
Sleep quality	██████░░░░ 64%	Silexan improves sleep secondary to anxiolysis; aromatherapy sleep meta-analyses positive but small and high-risk-of-bias
Depressive symptoms	██████░░░░ 56%	Meta-analysis of co-occurring depressive symptoms in anxious patients; no trial in primary major depression
Anti-inflammatory	█████░░░░░ 54%	Linalool/linalyl acetate reduce carrageenan oedema in rodents; no human data
Analgesic	█████░░░░░ 53%	Linalool antinociception via adenosine/NO/glutamate in rodents; human aromatherapy pain trials mixed
Antispasmodic	█████░░░░░ 51%	Linalyl acetate relaxes isolated smooth muscle; mechanism mapped, no clinical trial
Antimicrobial	█████░░░░░ 50%	In-vitro antibacterial/antifungal activity of the essential oil; prep matches topical use but no controlled human evidence
Neuroprotective	████░░░░░░ 43%	Animal cognition/oxidative-stress models only; constituent- and extract-level

1. Anxiety

This is the one indication where lavender reaches human-trial strength, and it is worth being precise about what was tested. The oral preparation Silexan (80 mg/day, a standardised soft-gel of L. angustifolia essential oil) beat placebo on the Hamilton Anxiety scale in subsyndromal (“subsyndromal”) anxiety ^{1Reference 1Kasper et al. · 2010RCTSilexan, an orally administered Lavandula oil preparation, is effective in the treatment of ‘subsyndromal’ anxiety disorder — randomized, double-blind, placebo-controlled trialView study →} and in diagnosed generalised anxiety disorder ^{2Reference 2Kasper et al. · 2014RCTLavender oil preparation Silexan is effective in generalized anxiety disorder — a randomized, double-blind comparison to placebo and paroxetineView study →}. A 2019 network meta-analysis and a 2023 meta-analysis of the pooled placebo-controlled trials confirmed a consistent, moderate anxiolytic effect ^{6,7Reference 6Yap et al. · 2019Meta-analysisEfficacy and safety of lavender essential oil (Silexan) capsules among patients suffering from anxiety disorders — network meta-analysisView study →Reference 7Dold et al. · 2023Meta-analysisEfficacy of Silexan in patients with anxiety disorders — a meta-analysis of randomized, placebo-controlled trialsView study →}. In head-to-head trials Silexan was non-inferior to 0.5 mg lorazepam ^{3Reference 3Woelk et al. · 2010RCTA multi-center, double-blind, randomised study of the Lavender oil preparation Silexan in comparison to Lorazepam for generalized anxiety disorder — randomized controlled trialView study →} and comparable to paroxetine, while a dose-ranging pooled analysis found 160 mg/day added benefit in more severe anxiety ^{5Reference 5Kasper et al. · 2017RCTSilexan in generalized anxiety disorder: investigation of the therapeutic dosage range in a pooled data set — randomized controlled trialView study →}. It also reduced the somatic (physical) symptoms of anxiety ^{9Reference 9von Känel et al. · 2021Meta-analysisTherapeutic effects of Silexan on somatic symptoms and physical health in patients with anxiety disorders — meta-analysisView study →} and, notably, did not produce withdrawal or rebound when stopped abruptly ^{8Reference 8Gastpar et al. · 2017RCTSilexan does not cause withdrawal symptoms even when abruptly discontinued — randomized controlled trialView study →} — a meaningful contrast with benzodiazepines. The honest limit: these results belong to one manufacturer’s standardised oral capsule; the anxiolytic dose is a concentrated swallowed essential oil, not the aromatherapy diffuser, the tea, or the 1:2 tincture in this monograph’s sidebar.

Gap: All positive anxiety data are for oral Silexan; there is no equivalent controlled evidence that the tincture or dried-flower tea delivers the same effect at the doses people actually use.

2. Sleep quality

Sleep improvement is real but largely downstream of the anxiolytic effect. In the Silexan trials, sleep disturbance improved as a secondary outcome, and a narrative review concluded the drug improves sleep chiefly by relieving the anxiety that disrupts it, rather than acting as a direct sedative ^{11Reference 11Seifritz et al. · 2022ReviewEffect of the anxiolytic drug silexan on sleep — a narrative reviewView study →}. Separately, inhaled-lavender aromatherapy has been pooled in several meta-analyses reporting better subjective sleep quality in adults and older adults ^{12,13Reference 12Shen et al. · 2026Meta-analysisThe sleep-enhancing effect of lavender essential oil in adults — a systematic review and meta-analysisView study →Reference 13Xu et al. · 2024Meta-analysisEffects of aromatherapy on sleep quality in older adults — a meta-analysisView study →} — but the constituent trials are small, unblinded by nature (the smell is obvious), and rated high risk of bias, so the effect size is uncertain. Objective (polysomnographic) confirmation is thin.

Gap: No trial shows lavender working as a primary hypnotic on objective sleep measures; the aromatherapy evidence is subjective and methodologically weak, and the oral-capsule benefit is secondary to anxiolysis.

3. Depressive symptoms

Lavender’s antidepressant signal is confined to depression that travels with anxiety. A 2023 meta-analysis found Silexan reduced co-occurring depressive symptoms in patients with subthreshold or generalised anxiety ^{10Reference 10Bartova et al. · 2023Meta-analysisBeneficial effects of Silexan on co-occurring depressive symptoms in patients with subthreshold anxiety — meta-analysisView study →}, and a dedicated RCT in mixed anxiety–depression showed benefit on both symptom clusters ^{4Reference 4Kasper et al. · 2016RCTEfficacy of Silexan in mixed anxiety–depression — a randomized, placebo-controlled trialView study →}. What is missing is any trial in primary major depressive disorder, where anxiety is not the driver.

Gap: The effect is on depressive symptoms secondary to anxiety; lavender has not been tested as a stand-alone antidepressant in diagnosed major depression.

4. Anti-inflammatory

The anti-inflammatory action is a constituent story. Linalool and linalyl acetate — together 60–80% of the oil — reduced carrageenan-induced paw oedema in rats, with linalool the more active of the two ^{17Reference 17Peana et al. · 2002AnimalAnti-inflammatory activity of linalool and linalyl acetate constituents of essential oils — rat modelView study →}. Follow-up work traced part of this to suppressed nitric-oxide formation ^{31Reference 31Peana et al. · 2006In vitroPeana, A. T., et al. (2006). (−)-Linalool inhibits in vitro NO formation: probable involvement in the antinociceptive activity — in vitro/animal model. Life Sciences. https://pubmed.ncbi.nlm.nih.gov/16137709/View study →} and adenosine-receptor signalling ^{18Reference 18Peana et al. · 2006AnimalInvolvement of adenosine A1 and A2A receptors in (−)-linalool-induced antinociception — animal modelView study →}. These are reproducible rodent and in-vitro findings, but no controlled human trial has tested lavender for an inflammatory condition, and the doses are of isolated compounds, not the whole herb.

Gap: Entirely preclinical; the human relevance of oedema-model data at achievable topical or oral doses is unknown.

5. Analgesic

Lavender’s mild analgesic reputation has a defined mechanism in animals: linalool produced antinociception in rodent pain models through adenosine A1/A2A receptors ^{18Reference 18Peana et al. · 2006AnimalInvolvement of adenosine A1 and A2A receptors in (−)-linalool-induced antinociception — animal modelView study →}, nitric-oxide modulation ^{31Reference 31Peana et al. · 2006In vitroPeana, A. T., et al. (2006). (−)-Linalool inhibits in vitro NO formation: probable involvement in the antinociceptive activity — in vitro/animal model. Life Sciences. https://pubmed.ncbi.nlm.nih.gov/16137709/View study →}, and dampened glutamatergic signalling, and it blunted carrageenan-induced hyperalgesia ^{19Reference 19Peana et al. · 2004AnimalEffects of (−)-linalool in the acute hyperalgesia induced by carrageenan, L-glutamate and prostaglandin E2 — rat modelView study →}. On the human side, inhaled-lavender aromatherapy has been trialled for procedural and post-operative pain with mixed, generally modest results, and is confounded by the difficulty of blinding an aroma. This is a plausible adjunct effect, not a demonstrated stand-alone analgesic.

Gap: Robust mechanism in rodents, but human evidence is limited to unblindable aromatherapy trials of variable quality; no data support the tincture as an analgesic.

6. Antispasmodic

The traditional use for cramping and colic maps onto real smooth-muscle pharmacology. Linalyl acetate, the oil’s other dominant monoterpene, relaxed isolated rat uterine smooth muscle ^{20Reference 20Koto et al. · 2006In vitroLinalyl acetate as a major ingredient of lavender essential oil relaxes the rabbit/rat smooth muscle — in vitro/animal modelView study →}, and classic mode-of-action work showed lavender oil relaxes guinea-pig and rat smooth muscle preparations, consistent with a cyclic-AMP-mediated, non-specific spasmolytic effect ^{21Reference 21Lis-Balchin et al. · 1999In vitroStudies on the mode of action of the essential oil of lavender (Lavandula angustifolia) — in vitro smooth-muscle studyView study →}. This is coherent, mechanistically mapped evidence — but it is all ex-vivo tissue and animal work; no clinical trial has tested lavender for menstrual, gut, or other spasm.

Gap: Mechanism is well described in isolated tissue, but there is no human trial for any spasmodic condition, including the dysmenorrhoea use claimed in the clinical-applications section.

7. Antimicrobial

Lavender essential oil shows antibacterial and antifungal activity in vitro, which is the pharmacology behind its topical use for minor skin infections. The active fraction is again the monoterpenes — linalool and terpinen-4-ol disrupt microbial membranes at the concentrations reached in undiluted or lightly diluted oil. Here the preparation actually matches the use: topical essential oil is what the in-vitro data model, unlike the anxiety story. What is absent is any controlled clinical trial showing the oil clears or prevents a real skin infection in people.

Gap: Consistent in-vitro activity, but no controlled human evidence; clinical efficacy for skin infection remains inferred from petri-dish MICs.

8. Neuroprotective

The neuroprotective and pro-cognitive claims are the most preliminary. Lavender oil improved scopolamine-induced memory deficits and lowered oxidative-stress markers in rats ^{22Reference 22Xu et al. · 2016AnimalProtective effect of lavender oil on scopolamine-induced cognitive deficits in mice — animal modelView study →}, and related Lavandula extracts protected neurons in ischaemia and 6-OHDA models. These are single-model animal studies with no human counterpart, and the effect is attributed variously to whole-oil, linalool, and minor constituents such as myrtenol.

Gap: Animal-model only, no clinical data; too early to call lavender neuroprotective in any human sense.

Mechanisms

Mechanism	Drives	Key compounds
Voltage-gated Ca²⁺-channel inhibition → reduced presynaptic glutamate release	anxiety, antispasmodic	linalool, linalyl acetate
5-HT1A serotonin-receptor modulation (shown on human PET; benzodiazepine/GABA pathway not required in animal dissection studies) 14,15,16Reference 14Baldinger et al. · 2014RCTEffects of Silexan on the serotonin-1A receptor and microstructure of the human brain — a randomized, placebo-controlled PET studyView study →Reference 15López et al. · 2017In vitroExploring pharmacological mechanisms of lavender (Lavandula angustifolia) essential oil on central nervous system targets — in vitroView study →Reference 16Chioca et al. · 2013AnimalAnxiolytic-like effect of lavender essential oil inhalation in mice: participation of serotonergic but not GABA-A/benzodiazepine neurotransmission — animal modelView study →	anxiety, depressive symptoms	whole essential oil, linalool
Adenosine A1/A2A signalling + nitric-oxide suppression	analgesic, anti-inflammatory	linalool
Eicosanoid/oedema pathway ↓	anti-inflammatory	linalool, linalyl acetate
cAMP-mediated smooth-muscle relaxation	antispasmodic	linalyl acetate
Microbial membrane disruption	antimicrobial	linalool, terpinen-4-ol

Clinical trials

Lavender is unusual among herbs in having a substantial registered and published trial programme, but it is almost entirely for the oral Silexan preparation in anxiety and related mood/sleep symptoms; other indications and other preparations remain preclinical.

Completed	Planned	Terminated	Preclinical
12+ (Silexan anxiety/mood/sleep RCTs)	ongoing (e.g. PTSD)	0 identified	~40+ (constituent & animal studies)

Last checked: July 2026.

Clinical Applications

Lavender is traditionally used topically for female conditions including dysmenorrhoea and PMS, on the basis of its antispasmodic and analgesic effects — though the human evidence here is limited to small aromatherapy/massage trials and isolated-tissue mechanism work ^{20,21Reference 20Koto et al. · 2006In vitroLinalyl acetate as a major ingredient of lavender essential oil relaxes the rabbit/rat smooth muscle — in vitro/animal modelView study →Reference 21Lis-Balchin et al. · 1999In vitroStudies on the mode of action of the essential oil of lavender (Lavandula angustifolia) — in vitro smooth-muscle studyView study →}. It’s also used topically for its antifungal and antibacterial effects, which rest on in-vitro activity of the oil rather than controlled clinical trials. Internally lavender is used for gastrointestinal complaints, including bloating, flatulence, and colic.

Lavender is best regarded as a nervine, but its mechanism is not the GABA story often repeated for it: the clearest mechanistic dissection found the anxiolytic effect depends on serotonergic (5-HT1A) transmission and was not blocked by flumazenil — i.e. it is not benzodiazepine/GABA-A-mediated — and human PET work points the same way ^{14,16Reference 14Baldinger et al. · 2014RCTEffects of Silexan on the serotonin-1A receptor and microstructure of the human brain — a randomized, placebo-controlled PET studyView study →Reference 16Chioca et al. · 2013AnimalAnxiolytic-like effect of lavender essential oil inhalation in mice: participation of serotonergic but not GABA-A/benzodiazepine neurotransmission — animal modelView study →}. Older claims that lavender reverses caffeine stimulation and inhibits acetylcholine release trace to isolated animal and in-vitro work and should not be read as established human effects.

Dosage

In research, lavender is almost always given as the standardised oral essential-oil softgel Silexan, dosed in milligrams — not as the dried-flower tea or the 1:2 tincture in the sidebar. Those preparations have not been shown to deliver the trialled effect.

Indication	Preparation	Dose	Est. dried-herb equivalent	Source
Anxiety (GAD / subsyndromal)	Silexan standardised oral essential-oil softgel	80 mg/day (up to 160 mg/day in more severe anxiety)	— (see note)	1,2,5Reference 1Kasper et al. · 2010RCTSilexan, an orally administered Lavandula oil preparation, is effective in the treatment of ‘subsyndromal’ anxiety disorder — randomized, double-blind, placebo-controlled trialView study →Reference 2Kasper et al. · 2014RCTLavender oil preparation Silexan is effective in generalized anxiety disorder — a randomized, double-blind comparison to placebo and paroxetineView study →Reference 5Kasper et al. · 2017RCTSilexan in generalized anxiety disorder: investigation of the therapeutic dosage range in a pooled data set — randomized controlled trialView study →
Mixed anxiety–depression	Silexan oral softgel	80 mg/day	—	4Reference 4Kasper et al. · 2016RCTEfficacy of Silexan in mixed anxiety–depression — a randomized, placebo-controlled trialView study →
Sleep (secondary to anxiolysis)	Silexan oral softgel	80 mg/day	—	11Reference 11Seifritz et al. · 2022ReviewEffect of the anxiolytic drug silexan on sleep — a narrative reviewView study →
Sleep / anxiety (aromatherapy)	Inhaled essential oil (diffusion / inhalation)	varies by trial (drops of oil, timed inhalation)	not applicable (inhaled)	12,13Reference 12Shen et al. · 2026Meta-analysisThe sleep-enhancing effect of lavender essential oil in adults — a systematic review and meta-analysisView study →Reference 13Xu et al. · 2024Meta-analysisEffects of aromatherapy on sleep quality in older adults — a meta-analysisView study →

Silexan is a concentrated distilled essential oil dosed in milligrams; the essential oil is steam-distilled and concentrated roughly 50–100× by weight from the flower, so there is no valid marker-% back-conversion to a dried-flower weight. The “est. dried-herb equivalent” column is intentionally left ”—” rather than invented — these are research doses, not recommendations.

Traditional Dosage

Western herbal texts use the dried flower or a liquid extract. These traditional doses are not interchangeable with the standardised-extract doses trialled above.

System	Preparation	Dose
Western herbal	Dried flower infusion (tea)	1–2 tsp dried flower per cup, 1–3× daily
Western herbal	Liquid extract 1:2	15–30 mL / week
Western herbal	Tincture 1:5 (45%)	~2–4 mL, up to 3× daily

Safety

Oral and inhaled lavender preparations are well tolerated in trials: the standardised oral essential oil Silexan showed a low adverse-event rate (mostly mild eructation/“lavender burps” and GI upset) and, importantly, produced no withdrawal or rebound on abrupt discontinuation ^{8Reference 8Gastpar et al. · 2017RCTSilexan does not cause withdrawal symptoms even when abruptly discontinued — randomized controlled trialView study →}. The main documented risk is topical: lavender oil is a recognised contact allergen, and its allergenicity rises sharply once linalool oxidises on air exposure, so aged or oxidised oil is more sensitising than fresh. The most debated concern is endocrine — case reports have linked repeated topical lavender (and tea tree) oil to prepubertal gynecomastia and premature thelarche in children, supported by in-vitro estrogenic/anti-androgenic and steroidogenic-CYP activity of the oil and its constituents ^{23,24,25,28,30Reference 23Henley et al. · 2007Case reportPrepubertal gynecomastia linked to lavender and tea tree oils — case series with in-vitro endocrine assaysView study →Reference 24Diaz et al. · 2016Prepubertal gynecomastia and chronic lavender exposure — report of three casesView study →Reference 25Ramsey et al. · 2019Case reportLavender products associated with premature thelarche and prepubertal gynecomastia — case reports and in-vitro endocrine-disruptor screeningView study →Reference 28Sharma et al. · 2024In vitroEffect of essential-oil components on the activity of steroidogenic cytochrome P450 — in vitroView study →Reference 30Hawkins et al. · 2020Systematic reviewThe relationship between lavender and tea tree essential oils and pediatric endocrine disorders — systematic reviewView study →}; however, an in-vivo uterotrophic assay of percutaneous lavender oil was negative and a formal toxicological reassessment judged linalool and linalyl acetate to lack meaningful endocrine potential at realistic exposures ^{26,27Reference 26Politano et al. · 2013AnimalUterotrophic assay of percutaneous lavender oil in immature female rats — animal model (negative)View study →Reference 27Hareng et al. · 2024ReviewCritical assessment of the endocrine potential of linalool and linalyl acetate — in-vitro/in-vivo reviewView study →}. The signal is unresolved but weighted toward caution for repeated skin application in prepubertal children. A dedicated RCT found oral Silexan did not reduce the efficacy of ethinylestradiol/levonorgestrel oral contraception ^{29Reference 29Heger-Mahn et al. · 2014RCTNo interacting influence of the lavender oil preparation Silexan on oral contraception — randomized controlled trialView study →}.

The traditional caution to avoid combining lavender with pharmaceutical sedatives is a reasonable theoretical concern (additive CNS depression), not a demonstrated interaction.

Scope note: interactions were only partially assessed in this research — a dedicated RCT ruled out an oral-contraceptive interaction ^{29Reference 29Heger-Mahn et al. · 2014RCTNo interacting influence of the lavender oil preparation Silexan on oral contraception — randomized controlled trialView study →}, but the sedative-synergy caution is theoretical and no systematic CYP/drug-interaction panel was found. The paediatric endocrine signal rests on case reports plus in-vitro assays, with negative in-vivo and reassessment data on the other side; it is unresolved, not settled.

Pregnancy & lactation

Verdict: Not established — avoid concentrated/oral preparations. Lavender’s safety in pregnancy has not been formally studied in controlled trials, and its constituents show measurable (if contested) endocrine activity in vitro, so the concentrated essential oil and oral Silexan should be avoided during pregnancy and lactation in the absence of safety data ^{23,25,27Reference 23Henley et al. · 2007Case reportPrepubertal gynecomastia linked to lavender and tea tree oils — case series with in-vitro endocrine assaysView study →Reference 25Ramsey et al. · 2019Case reportLavender products associated with premature thelarche and prepubertal gynecomastia — case reports and in-vitro endocrine-disruptor screeningView study →Reference 27Hareng et al. · 2024ReviewCritical assessment of the endocrine potential of linalool and linalyl acetate — in-vitro/in-vivo reviewView study →}. Culinary amounts of the dried flower and brief topical/aromatherapy use are generally regarded as low-risk, but this reflects traditional use and absence of reports rather than positive safety testing.

Scope note: pregnancy and lactation were not specifically researched — this verdict is precautionary, not a finding of harm. It corrects the page’s earlier “No adverse reactions expected” statement, which is not supported by primary evidence.

References

1. Kasper, S., et al. (2010). Silexan, an orally administered Lavandula oil preparation, is effective in the treatment of ‘subsyndromal’ anxiety disorder — randomized, double-blind, placebo-controlled trial. International Clinical Psychopharmacology. https://pubmed.ncbi.nlm.nih.gov/20512042/
2. Kasper, S., et al. (2014). Lavender oil preparation Silexan is effective in generalized anxiety disorder — a randomized, double-blind comparison to placebo and paroxetine. International Journal of Neuropsychopharmacology. https://pubmed.ncbi.nlm.nih.gov/24456909/
3. Woelk, H., & Schläfke, S. (2010). A multi-center, double-blind, randomised study of the Lavender oil preparation Silexan in comparison to Lorazepam for generalized anxiety disorder — randomized controlled trial. Phytomedicine. https://pubmed.ncbi.nlm.nih.gov/19962288/
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32. ISO 3515:2002. Oil of lavender (Lavandula angustifolia Mill.). International Organization for Standardization. (Gas-chromatographic composition limits.)
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34. Missouri Botanical Garden Plant Finder — Lavandula angustifolia — [botanical/distribution reference]. https://www.missouribotanicalgarden.org/plantfinder/PlantFinderDetails.aspx?taxonid=281393