Lavender (Lavandula angustifolia) is arguably the most widely used aromatherapy ingredient in the world. Its association with calm and relaxation is culturally universal, but the clinical evidence for lavender goes considerably beyond pleasant associations — particularly for an oral preparation that has been studied in multiple RCTs for anxiety disorders.
While lavender is not native to Ireland — it prefers the drier, sunnier climates of the Mediterranean — it is one of the most widely grown garden herbs across the island. Lavender sachets in drawers, lavender pillow sprays, and lavender aromatherapy diffusers are common features of Irish homes, and lavender tea is increasingly popular in health-conscious circles. Lavender essential oil is the single most purchased essential oil in the world by volume.
Lavender essential oil contains over 100 identified compounds. The primary bioactive components are linalool (comprising 25–45% of the oil) and linalool acetate (25–45%). Both compounds have demonstrated anxiolytic and sedative properties in preclinical models. Linalool appears to act on GABA-A receptors (the same receptor system involved in benzodiazepine action) and also modulates NMDA and serotonin receptors. It also shows voltage-gated calcium channel blocking activity in neurons.
Inhaled lavender has been studied in numerous trials, particularly in clinical settings. Evidence from systematic reviews (including Cho et al. 2013 in Evidence-Based Complementary and Alternative Medicine) suggests lavender aromatherapy reduces anxiety scores in peri-operative patients, ICU patients, and in various anxiety measures. A 2019 study in Phytomedicine found lavender inhalation significantly reduced state anxiety in dental patients.
However, aromatherapy studies are inherently difficult to blind properly — participants usually know what they're smelling — which limits the quality of evidence. Effect sizes vary and placebo response rates are high in anxiety trials.
The most impressive clinical evidence for lavender comes from Silexan, an oral lavender oil preparation licensed in Germany under the brand name Lasea® for anxiety disorders. A series of RCTs by Kasper and colleagues at the Medical University of Vienna have examined Silexan in generalised anxiety disorder:
Kasper et al. (2010, Phytomedicine) randomised 216 patients with mixed anxiety disorder to Silexan 80 mg/day or placebo for 6 weeks. Silexan produced significantly greater reductions in HAM-A (Hamilton Anxiety) scores than placebo.
A 2014 non-inferiority trial (Kasper et al., International Journal of Neuropsychopharmacology) found Silexan 80 mg/day comparable to lorazepam 0.5 mg/day for anxiety reduction, with a significantly better tolerability profile (no sedation, no dependency).
A 2015 trial (Kasper et al.) in 539 patients with GAD found both 80 mg/day and 160 mg/day Silexan produced significantly greater improvements in HAM-A scores than placebo, with the 160 mg dose producing greater effects. These are high-quality, well-powered trials that provide genuine evidence for oral lavender oil as an anxiolytic.
Both aromatherapy and oral lavender preparations have some evidence for improving sleep quality. A 2015 crossover trial found lavender aromatherapy improved sleep quality scores in college students. The Silexan RCTs also demonstrated improvements in sleep quality as a secondary outcome. Lavender pillow sprays remain popular among people with mild sleep difficulties, and the evidence basis, while not robust, is consistent with a mild, safe sedative effect.
| Claim | Evidence Level | Source |
|---|---|---|
| Oral lavender oil (Silexan) reduces anxiety in GAD | Strong | Kasper et al. 2010, 2014, 2015 RCTs |
| Silexan comparable to lorazepam for anxiety | Moderate | Kasper et al. 2014 non-inferiority RCT |
| Lavender aromatherapy reduces procedural anxiety | Moderate | Multiple RCTs (blinding limitations) |
| Lavender improves sleep quality | Limited | Small trials; consistent direction, limited size |
| Linalool acts on GABA-A receptors | Moderate (pharmacological) | Multiple preclinical studies |
Aromatherapy: A few drops of lavender essential oil in a diffuser, on a pillow, or in a warm bath. Inhaling lavender steam before bed is a practical sleep preparation ritual with low risk.
Topical: Diluted in a carrier oil (2–3% concentration, approximately 6–9 drops per 10 ml of carrier oil) for massage. Never apply undiluted essential oil directly to skin.
Lavender tea: Dried lavender flowers steeped in hot water produce a mild, floral tea. Active compound concentration is low compared to aromatherapy or oil capsules, but pleasant and relaxing as a bedtime ritual.
Oral capsules: Silexan (Lasea®) is available in some European countries as a licensed medicine. Similar lavender oil oral capsules are available in Irish health shops, though formulation standardisation varies.
Topical use: Lavender essential oil should always be diluted before skin application. Undiluted essential oils can cause chemical burns and sensitisation. Perform a patch test before widespread use. Avoid contact with eyes and mucous membranes.
Hormonal effects (prepubertal boys): Case reports have linked lavender-containing products to gynaecomastia (breast tissue development) in prepubertal boys. Laboratory studies suggest lavender (and tea tree) oil may have weak oestrogenic and anti-androgenic activity. While the evidence for this effect is limited to case reports, it is prudent to avoid topical lavender-containing products (lotions, soaps) for regular use on young boys, and this concern does not apply to incidental aromatherapy exposure.
Sedative medications: Lavender may enhance the sedative effects of benzodiazepines and other CNS depressants at oral supplement doses. Do not combine with prescribed sleeping medications without discussion with your GP.
Pregnancy: Lavender aromatherapy in moderate amounts is widely considered safe in pregnancy. High-dose oral lavender oil preparations should be discussed with a midwife or GP.
Oral lavender oil side effects: Silexan trials report belching with a lavender taste as the most common side effect (mild and transient). GI discomfort reported in a small number of participants.
Lavender's evidence base is more substantial than most people realise. Oral lavender oil (Silexan) has genuine, high-quality RCT evidence for anxiety comparable to some pharmaceutical anxiolytics — without the sedation and dependency risks. Aromatherapy lavender has more limited but consistent evidence for situational anxiety. For mild-to-moderate anxiety and sleep difficulties, lavender represents an accessible, well-tolerated, and evidence-grounded option that bridges the gap between pleasant ritual and clinical intervention.
For lavender essential oils and relaxation products, shop at our partner
Shop at The Honey Pot →