Lavender oil: Evidence, Trial Doses & Interactions

About Lavender oil

An essential oil distilled from lavender flowers. One specific orally administered preparation, standardised to linalool and linalyl acetate in a gelatin capsule, has been studied as a medicine for anxiety.

Lavender is an unusual case where a specific oral preparation has real randomised trial data in generalised anxiety disorder — including comparisons against paroxetine and lorazepam — while the aromatherapy literature it is usually confused with is much weaker. The oral trials were largely funded by the German manufacturer of the licensed product, and ordinary lavender essential oil sold for diffusers is not the same thing and is not intended to be swallowed.

Sold as

Oral capsule of standardised oil, Essential oil for aromatherapy, Topical dilution, Dried flowers

Standardised to

The studied oral preparation is standardised to 36.8% linalool and 34.2% linalyl acetate — a product without this marker may not resemble what was studied.

Also known as

Silexan, True lavender, Lavender essential oil

Regulation: The studied oral lavender oil preparation is a licensed medicine for anxiety in Germany and several other countries; in the US and UK it is sold as a supplement without that assessment. Essential oil intended for aromatherapy is not formulated or tested for swallowing.

What the research used

The amounts, forms and durations published trials of Lavender oil actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

Studied for Anxiety symptoms
80–160 mg
Moderate
Oral capsule of standardised lavender oil, once daily · 6–10 weeks
These trials used one specific licensed preparation and were mostly manufacturer-funded. Generic lavender oil capsules have not been shown equivalent, and diffuser oil is a different product entirely.
Studied for Aromatherapy
2–5 drops
Not enough
Inhaled or diffused essential oil
Aromatherapy trials cannot be blinded — participants can smell which group they are in — which is the central methodological problem with that literature.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

Any time
Not enough
The oral trials used a single daily capsule at no specified time. No comparison of dosing times exists.
Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

Stress and anxiety

Mental Wellbeing

Moderate evidence

Several randomised trials of one standardised oral lavender oil preparation report reduced anxiety scores compared with placebo, with two active-comparator trials suggesting it performed similarly to low-dose paroxetine or lorazepam. Nearly all of the trials were funded by the manufacturer and the evidence concerns that product rather than lavender generally.

What may be going on: Linalool has been reported to modulate voltage-gated calcium channels in preclinical work; the mechanism in people is not established.

Moderate evidence. Several human studies point the same way, with real caveats.

View the 1 source

Effects of lavender on anxiety: A systematic review and meta-analysis.(opens in a new tab)
Meta-analysis · Phytomedicine : international journal of phytotherapy and phytopharmacology · 2019 · PMID 31655395

Deep research mode adds each paper’s own conclusion and stated limitations.

Sleep quality

Sleep

Limited evidence

Some trials report better subjective sleep alongside reduced anxiety, though sleep was usually a secondary outcome. Aromatherapy sleep studies cannot be properly blinded, which limits what they can show.

Limited evidence. Early human work, or mostly lab and animal research.

View the 2 sources

Effects of aromatherapy on sleep quality and anxiety of patients.(opens in a new tab)
Randomised controlled trial · Nursing in critical care · 2017 · PMID 26211735
Lavender essential oil on postmenopausal women with insomnia: Double-blind randomized trial.(opens in a new tab)
Randomised controlled trial · Complementary therapies in medicine · 2021 · PMID 33905827

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

Worth knowing
Essential oil is not for swallowing
Lavender essential oil sold for diffusers or massage is not formulated for internal use, and ingesting undiluted essential oils has caused burns, vomiting and central nervous system depression, particularly in children.
Worth knowing
Reports of gynaecomastia in boys
Case reports describe breast development in prepubertal boys using lavender-containing topical products, with laboratory work showing weak oestrogenic and antiandrogenic activity. The evidence is contested but the reports are documented.
Interaction
Additive sedation
Interacts withBenzodiazepines, alcohol, sedatives
Drowsiness may add to benzodiazepines, alcohol and other sedatives, and belching with a lavender aftertaste is the most common reported effect of the oral capsules.
Allergy
Contact dermatitis
Oxidised lavender oil is a recognised contact allergen, and topical use can cause rash in sensitised people.
Avoid
Pregnancy
Oral lavender oil preparations have not been studied in pregnancy or breastfeeding.

Lavender oil

What lavender oil may help with

About Lavender oil

What the research used

When it was taken

Any time

The evidence in depth

Stress and anxiety

Sleep quality

Things to know

Essential oil is not for swallowing

Reports of gynaecomastia in boys

Additive sedation

Contact dermatitis

Pregnancy

What lavender oil may help with

About Lavender oil

What the research used

When it was taken

🕐Any time

The evidence in depth

Stress and anxiety

Sleep quality

Things to know

Essential oil is not for swallowing

Reports of gynaecomastia in boys

Additive sedation

Contact dermatitis

Pregnancy

Any time