Lavender: Difference between revisions

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| plant_part = Dried flower (inflorescence); essential oil distilled from fresh flowers.

| image =

| intro = Lavandula angustifolia Mill. -- true lavender, English lavender -- is a perennial aromatic shrub of the western Mediterranean garrigue, whose name descends from the Latin lavare, to wash, a record of the centuries it spent in the Roman bathhouse before it entered the clinic. Among aromatic herbs it holds a singular evidence record: a standardized oral preparation of its essential oil is the only essential-oil plant medicine to have been evaluated against a prescription anxiolytic in a randomized controlled trial and found non-inferior. Between the Roman bath and that trial stretches two thousand years of uninterrupted medicinal use for the same cluster of indications: anxiety, sleeplessness, and pain of the head.

| intro = ''Lavandula angustifolia'' Mill. -- true lavender, English lavender -- is a perennial aromatic shrub of the western Mediterranean garrigue, whose name descends from the Latin lavare, to wash, a record of the centuries it spent in the Roman bathhouse before it entered the clinic. Among aromatic herbs it holds a singular evidence record: a standardized oral preparation of its essential oil is the only essential-oil plant medicine to have been evaluated against a prescription anxiolytic in a randomized controlled trial and found non-inferior. Between the Roman bath and that trial stretches two thousand years of uninterrupted medicinal use for the same cluster of indications: anxiety, sleeplessness, and pain of the head.

| history = The name came first. Pliny the Elder in the first century of the common era recorded the use of nardus gallicus -- a lavender relative -- as a bath additive throughout the Roman world, and later writers formalized the association with lavare.{{citation needed}} The Greco-Roman medicinal plant was not L. angustifolia but its cousin Lavandula stoechas -- the French or Spanish lavender, high in camphor and pharmacologically distinct -- which Dioscorides in his De Materia Medica (1st century CE) recorded for headache, nausea, and disorders of the lung.{{citation needed}} L. angustifolia entered European medicine through the medieval monastic garden, where Benedictine and Cistercian communities cultivated it as a strewing herb, a wash for wounds, and a remedy for the head -- the "vapours" of nervous complaint that would occupy it for centuries thereafter.

| history = The name came first. Pliny the Elder in the first century of the common era recorded the use of nardus gallicus -- a lavender relative -- as a bath additive throughout the Roman world, and later writers formalized the association with lavare.{{citation needed}} The Greco-Roman medicinal plant was not ''L. angustifolia'' but its cousin ''Lavandula stoechas'' -- the French or Spanish lavender, high in camphor and pharmacologically distinct -- which Dioscorides in his De Materia Medica (1st century CE) recorded for headache, nausea, and disorders of the lung.{{citation needed}} ''L. angustifolia'' entered European medicine through the medieval monastic garden, where Benedictine and Cistercian communities cultivated it as a strewing herb, a wash for wounds, and a remedy for the head -- the "vapours" of nervous complaint that would occupy it for centuries thereafter.

John Parkinson, the apothecary who served James I, wrote in his Theatrum Botanicum of 1640 that lavender was of "especiall good use for all griefes and paines of the head and brain."{{citation needed}} Tudor England had already made lavender domestic property: lavender water was among the standard preparations of every gentlewoman's stillroom, the dried flowers were stuffed into pillows against insomnia, and bundles were laid between linens to discourage moths -- a use continuous from Roman times. Queen Elizabeth I reportedly consumed lavender conserve daily as a remedy for her migraines.{{citation needed}}

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The German Commission E formally approved lavender flower for mood disturbances, restlessness, and insomnia in 1990, giving it a regulatory foundation in Germany at a time when most European herbal preparations lacked one. That approval rested on traditional use rather than clinical trial evidence; the trial evidence came later. Schwabe Pharmaceuticals developed Silexan -- a standardized pharmaceutical-grade oral lavender oil capsule -- in the 2000s and conducted a series of randomized controlled trials that collectively produced the most rigorous clinical evidence base of any aromatic herb medicine. The transition from bathhouse plant to evidence-based anxiolytic took roughly two thousand years and one burned hand.

| taxonomy = Lavandula angustifolia Mill. (synonyms: L. officinalis Chaix, L. vera DC.) belongs to tribe Ocimeae, family Lamiaceae, one of approximately 40 species in the genus Lavandula. The genus name derives from lavare (to wash); the species epithet angustifolia (narrow-leaved) distinguishes it from broader-leaved relatives. Four species and one hybrid group carry the majority of commercial and medicinal significance.

| taxonomy = ''Lavandula angustifolia'' Mill. (synonyms: ''L. officinalis'' Chaix, ''L. vera'' DC.) belongs to tribe Ocimeae, family Lamiaceae, one of approximately 40 species in the genus ''Lavandula''. The genus name derives from lavare (to wash); the species epithet angustifolia (narrow-leaved) distinguishes it from broader-leaved relatives. Four species and one hybrid group carry the majority of commercial and medicinal significance.

L. angustifolia, true lavender or English lavender, produces the finest-quality essential oil -- highest in linalool and linalyl acetate, lowest in camphor -- and is the medicinal and perfumery standard against which other species are measured. It is the species from which Silexan is produced.

''L. angustifolia'', true lavender or English lavender, produces the finest-quality essential oil -- highest in linalool and linalyl acetate, lowest in camphor -- and is the medicinal and perfumery standard against which other species are measured. It is the species from which Silexan is produced.

L. latifolia, spike lavender, yields a higher volume of oil per plant but of coarser character: camphor and 1,8-cineole content are markedly higher, linalyl acetate lower; the oil is sharper and used in industrial applications, cheaper perfumery, and traditional preparations distinct from those of angustifolia.

''L. latifolia'', spike lavender, yields a higher volume of oil per plant but of coarser character: camphor and 1,8-cineole content are markedly higher, linalyl acetate lower; the oil is sharper and used in industrial applications, cheaper perfumery, and traditional preparations distinct from those of angustifolia.

L. x intermedia, lavandin, is a sterile hybrid of angustifolia and latifolia that dominates commercial Provence cultivation today; it produces the greatest oil yield per hectare, and its oil is the principal ingredient in most mass-market lavender products. Lavandin oil is not equivalent to true lavender oil for medicinal purposes: camphor content is substantially higher, and linalyl acetate lower.

L. stoechas, French or Spanish lavender, is visually distinguished by its butterfly-wing bracts atop the flower spike; its chemistry diverges considerably from L. angustifolia, being rich in camphor and fenchone. It was the medicinal lavender of Greco-Roman antiquity but is not the species behind modern anxiolytic research or the Western clinical herbal tradition.

''L. stoechas'', French or Spanish lavender, is visually distinguished by its butterfly-wing bracts atop the flower spike; its chemistry diverges considerably from ''L. angustifolia'', being rich in camphor and fenchone. It was the medicinal lavender of Greco-Roman antiquity but is not the species behind modern anxiolytic research or the Western clinical herbal tradition.

The medicinal parts of L. angustifolia are the dried flower (inflorescence, harvested before full opening to maximize volatile oil content) and the essential oil steam-distilled from fresh flowers. The Pharmacopoeia Europaea monograph ~~Lavandulae~~ flos specifies a minimum essential oil content in the dried inflorescence.{{citation needed}}

The medicinal parts of ''L. angustifolia'' are the dried flower (inflorescence, harvested before full opening to maximize volatile oil content) and the essential oil steam-distilled from fresh flowers. The Pharmacopoeia Europaea monograph ''Lavandula''e flos specifies a minimum essential oil content in the dried inflorescence.{{citation needed}}

Wild L. angustifolia populations occur on exposed limestone hillsides in Provence, the Apennines, the Dalmatian coast, and the mountains of Spain and Greece. The English Pilgrims transported lavender to New England in 1620; it has naturalized in temperate climates worldwide without becoming invasive.{{citation needed}}

Wild ''L. angustifolia'' populations occur on exposed limestone hillsides in Provence, the Apennines, the Dalmatian coast, and the mountains of Spain and Greece. The English Pilgrims transported lavender to New England in 1620; it has naturalized in temperate climates worldwide without becoming invasive.{{citation needed}}

| traditional_uses = '''Western herbal medicine (primary centroid)'''

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| pharmacology = '''Volatile oil constituents and mechanism'''

The essential oil of L. angustifolia consists primarily of linalool (25 to 45 percent), a monoterpene alcohol, and linalyl acetate (25 to 45 percent), its acetic acid ester.{{citation needed}} These two compounds account for the characteristic lavender fragrance and are the principal pharmacologically active constituents in oral Silexan. Camphor and 1,8-cineole -- constituents responsible for the sharper character of inferior species and for adulteration of true lavender oil with cheaper lavandin -- are present at less than one and less than two percent respectively in genuine L. angustifolia oil, and their presence in high concentration is a marker of species substitution or adulteration.

The essential oil of ''L. angustifolia'' consists primarily of linalool (25 to 45 percent), a monoterpene alcohol, and linalyl acetate (25 to 45 percent), its acetic acid ester.{{citation needed}} These two compounds account for the characteristic lavender fragrance and are the principal pharmacologically active constituents in oral Silexan. Camphor and 1,8-cineole -- constituents responsible for the sharper character of inferior species and for adulteration of true lavender oil with cheaper lavandin -- are present at less than one and less than two percent respectively in genuine ''L. angustifolia'' oil, and their presence in high concentration is a marker of species substitution or adulteration.

At the receptor level, two principal mechanisms have been characterized for the oral route.

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Inhalation delivers linalool and linalyl acetate via the olfactory mucosa and pulmonary absorption, with systemic concentrations substantially lower than oral administration; this accounts for the smaller effect sizes in aromatherapy trials relative to oral Silexan studies. The two routes are pharmacologically comparable in target but not in pharmacokinetic exposure.

Topically, lavender essential oil has demonstrated broad-spectrum antibacterial and antifungal activity in vitro, including against methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans, via disruption of microbial cell membrane integrity; wound-healing acceleration has been shown in animal models.{{citation needed}}

Topically, lavender essential oil has demonstrated broad-spectrum antibacterial and antifungal activity in vitro, including against methicillin-resistant ''Staphylococcus aureus'' (MRSA) and ''Candida albicans'', via disruption of microbial cell membrane integrity; wound-healing acceleration has been shown in animal models.{{citation needed}}

| clinical_evidence = The clinical evidence base for lavender divides sharply along route of administration. Oral Silexan (standardized lavender oil, 80 mg/day) has been evaluated in a series of double-blind randomized controlled trials; inhalation aromatherapy has been evaluated in a larger number of smaller trials with more modest and more variable effect sizes. The two evidence bodies should not be conflated.

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The antimicrobial activity documented in vitro -- including activity against MRSA -- has not been translated into powered clinical trials. The topical wound-healing tradition has animal-model support but no placebo-controlled clinical trial data in humans.

| preparations = Dried flower (inflorescence): harvested before full bloom, dried at low temperature to preserve volatile oil; used for infusion, sachets, and as the starting material for tincture and essential oil production. Genuine lavender flower carries an immediately recognizable sweet-floral fragrance without camphor sharpness; camphoraceous character indicates L. latifolia or lavandin substitution.

| preparations = Dried flower (inflorescence): harvested before full bloom, dried at low temperature to preserve volatile oil; used for infusion, sachets, and as the starting material for tincture and essential oil production. Genuine lavender flower carries an immediately recognizable sweet-floral fragrance without camphor sharpness; camphoraceous character indicates ''L. latifolia'' or lavandin substitution.

Essential oil: steam-distilled from fresh flowers; genuine L. angustifolia oil contains 25 to 45 percent linalool and 25 to 45 percent linalyl acetate, with camphor below 1 percent; these parameters distinguish true lavender from adulterated or substitute species. For topical use, always dilute in carrier oil (2 to 5 percent); neat application to intact skin carries some allergy risk even with true lavender oil, and dilution is the standard of practice.

Essential oil: steam-distilled from fresh flowers; genuine ''L. angustifolia'' oil contains 25 to 45 percent linalool and 25 to 45 percent linalyl acetate, with camphor below 1 percent; these parameters distinguish true lavender from adulterated or substitute species. For topical use, always dilute in carrier oil (2 to 5 percent); neat application to intact skin carries some allergy risk even with true lavender oil, and dilution is the standard of practice.

Silexan (brand name Lasea; Schwabe Pharmaceuticals): a standardized pharmaceutical-grade oral lavender oil capsule formulated for gastrointestinal absorption; manufactured at pharmaceutical quality standards with defined linalool and linalyl acetate content. This preparation is not equivalent to and should not be substituted by tipping commercial essential oil into food or capsules: solubility, concentration, solvent matrix, and quality standards differ fundamentally. Silexan is a prescription medicinal product in Germany.

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Following inhalation, linalool is absorbed via the pulmonary mucosa and by olfactory epithelium; plasma concentrations are substantially lower than after oral administration of an equivalent linalool dose, consistent with the smaller effect sizes observed in aromatherapy relative to oral-Silexan trials.

| interactions = Central nervous system depressants: theoretical additive sedation with benzodiazepines, alcohol, opioid analgesics, barbiturates, antihistamines, and sedating herbal medicines including valerian (Valeriana officinalis), kava (Piper methysticum), hops (Humulus lupulus), and passionflower (Passiflora incarnata). The clinical significance of this interaction at Silexan's standard 80 mg/day dose has not been formally evaluated; caution is appropriate when combining Silexan with benzodiazepines in patients transitioning from one agent to the other. The Woelk and Schlaefke (2010) trial documented successful lorazepam discontinuation in patients switched to Silexan,<ref name="woelk2010"/> suggesting that substitution is clinically feasible, but cross-tapering should be supervised.

| interactions = Central nervous system depressants: theoretical additive sedation with benzodiazepines, alcohol, opioid analgesics, barbiturates, antihistamines, and sedating herbal medicines including valerian (''Valeriana officinalis''), kava (''Piper methysticum''), hops (''Humulus lupulus''), and passionflower (''Passiflora incarnata''). The clinical significance of this interaction at Silexan's standard 80 mg/day dose has not been formally evaluated; caution is appropriate when combining Silexan with benzodiazepines in patients transitioning from one agent to the other. The Woelk and Schlaefke (2010) trial documented successful lorazepam discontinuation in patients switched to Silexan,<ref name="woelk2010"/> suggesting that substitution is clinically feasible, but cross-tapering should be supervised.

Cytochrome P450: in vitro data at suprapharmacological concentrations suggest possible inhibition of CYP2C9 and CYP3A4 by lavender oil constituents. No pharmacokinetic interaction has been documented in clinical trials at 80 mg/day; the relevance of in vitro findings to standard clinical dosing is uncertain. No dose adjustment of co-administered medicines is presently supported by clinical evidence.

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German Commission E (1990): lavender flower approved for mood disturbances with restlessness and sleep disturbances, and nervous stomach conditions; covers traditional oral preparations (infusion, tincture) based on traditional use rather than clinical trial evidence.

EMA HMPC: positive assessment of lavender flower as a traditional herbal medicinal product for mild anxiety and sleep disturbance; traditional use listing under the EU Traditional Herbal Medicinal Products Directive (Directive 2004/24/EC). The EMA HMPC opinion does not cover Silexan, which was developed and approved as a distinct pharmaceutical medicinal product under a separate regulatory pathway.<ref name="ema-hmpc-lavender">European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Community herbal monograph on Lavandula angustifolia P. Mill., flos. EMA/HMPC/734125/2010. First published: 13 June 2012. https://www.ema.europa.eu/en/medicines/herbal/lavandulae-flos.</ref>

EMA HMPC: positive assessment of lavender flower as a traditional herbal medicinal product for mild anxiety and sleep disturbance; traditional use listing under the EU Traditional Herbal Medicinal Products Directive (Directive 2004/24/EC). The EMA HMPC opinion does not cover Silexan, which was developed and approved as a distinct pharmaceutical medicinal product under a separate regulatory pathway.<ref name="ema-hmpc-lavender">European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Community herbal monograph on ''Lavandula angustifolia'' P. Mill., flos. EMA/HMPC/734125/2010. First published: 13 June 2012. https://www.ema.europa.eu/en/medicines/herbal/lavandulae-flos.</ref>

Silexan (Lasea; Schwabe Pharmaceuticals): approved as a prescription medicinal product (not a traditional herbal product) in Germany and some other EU member states specifically for the treatment of generalized anxiety disorder, based on the RCT program described above. This is the most stringent regulatory status achieved by any essential-oil preparation in the EU regulatory framework.

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