GradedHealth

Aromatherapy for sleep, anxiety and low mood: what 27 trials found

A 2025 review of 2,072 adults found inhaled essential oils improved sleep, anxiety and depression scores, but trials were small and most were unblinded.

Published October 2026

Short answer

Inhaled essential oils modestly improved sleep, anxiety and mood scores in a 27-trial review. Most trials were small and unblinded, so the true size of the benefit is uncertain. Evidence grade C (Limited). Meta-analysis of 27 mostly small, unblinded randomised trials with very high heterogeneity (I2 85-97%), suspected publication bias and self-rated outcomes; downgraded for inconsistency and risk of bias.

Key takeaways

  • A 2025 review of 27 trials in 2,072 adults with insomnia plus another illness found inhaled essential oils improved sleep-quality scores by about 2.9 points on the 21-point PSQI scale [1].
  • Anxiety scores were about 4 points lower and depression scores about 10 points lower, but results varied widely and only two of the 27 trials reported blinding [1].
  • Other sleep reviews agree: 34 studies of inhaled oils [2], 30 studies in adults and older adults [3], 10 studies in older adults [4] and 13 trials in hospital heart patients [5] all found improvements.
  • For dementia-related agitation the evidence conflicts: a 2020 Cochrane review found no convincing benefit [6], while newer meta-analyses report better agitation and behaviour scores [7][8].
  • Cancer pain did not improve in a 2024 meta-analysis [9], and essential oils can cause skin allergies and must not be swallowed [10][11].

What the study did

The 2025 review pooled 27 randomised trials in 2,072 adults who had insomnia along with another condition, such as heart disease, cancer, kidney dialysis, a psychiatric illness or recovery from fracture surgery [1]. Participants inhaled essential oils - lavender and blends among them, some delivered through sachets and medicated pillows - while comparison groups received usual care, a placebo or another treatment, for a week or less up to more than a month [1]. The main measure was the Pittsburgh Sleep Quality Index (PSQI), a 21-point questionnaire where lower scores mean better sleep, plus anxiety and depression scales [1].

What it found

Sleep quality improved: pooling 24 trials with 1,864 patients, the aromatherapy groups scored 2.9 points lower on the PSQI than controls (95% confidence interval 2.0 to 3.9 points better) [1]. Six parts of the questionnaire improved, including time to fall asleep and sleep efficiency [1]. Anxiety scores were about 4 points lower (9 trials, 802 patients) and depression scores about 10 points lower (5 trials, 458 patients) [1]. But results differed widely from trial to trial, the funnel plots suggested publication bias, and the reviewers rated the certainty of the evidence only average [1]. No adverse reactions were reported in the included trials [1].

How it fits

Earlier reviews of sleep point the same way: a review of 34 studies of inhaled aromatherapy found a moderate average improvement [2], one of 30 studies in adults and older adults found similar results [3], and one of 10 studies in older adults (692 people) found better sleep scores, although only 2 of those 10 trials were blinded [4]. In hospitalised heart patients, 13 trials with 740 people found a moderate improvement in sleep quality [5].

Anxiety results repeat elsewhere: anxiety scores fell across 32 trials [12] and across 20 studies of 1,717 adults waiting for surgery [13]. A review of 32 trials found depressive symptoms improved moderately, though not in pregnant or postpartum women [14]. Lavender has been reviewed on its own and reduced anxiety and depression scores [15].

For dementia, reviews disagree: a 2020 Cochrane review of 13 trials (708 care-home residents) found no convincing benefit for agitation or behaviour problems, and said harms were badly reported [6]. Newer meta-analyses of 15 trials each report better agitation and behaviour scores, especially with at least three weeks of use [7][8].

Pain is also mixed: a 2024 meta-analysis of 15 cancer trials found no significant effect on pain [9], while a 2019 review of 17 labour trials found less pain in the transition phase and a shorter active phase of labour [16]; an older Cochrane review of 2 labour trials found no difference [17]. For nausea and vomiting during cancer treatment, a 2024 review of 25 trials found a moderate improvement, mostly for nausea, with peppermint oil particularly successful [18], and a 2026 review of 26 trials in 2,912 cancer patients reported better sleep, fatigue, anxiety and depression scores and fewer vomiting episodes over 24 hours [19].

Among specific oils, rose oil (Rosa damascena) improved anxiety, stress and sleep scores across 28 trials [20]; used on the skin rather than inhaled, tea tree oil modestly reduced acne severity across 7 studies of 445 people [21].

Aromatherapy looks low-risk in the trials, but oils applied to the skin can cause allergic reactions, most often when used undiluted [10], and in one dermatology database 8.3% of 10,930 patients reacted to at least one oil [22]. Oils should not be swallowed: a man who drank camphor oil had seizures and needed intensive care [11], and concentrated tea tree oil poisoned 443 dogs and cats in pet poison-control records [23]. Strong scents can worsen breathing in people with asthma [24], and menthol-type rubs should not go under a small child's nose - a toddler became severely short of breath after this [25]. The Aromatherapy topic page has the full safety list.

Limits

The main caveat is blinding: people can tell whether they are inhaling a scented oil, and 25 of the 27 trials did not report any blinding [1]. Six of the 27 were master's theses rather than journal articles, results varied enormously between studies, and the funnel plots suggest positive trials are more likely to be published [1]. Outcomes were self-rated questionnaires and most trials were short, so long-term effects are unknown [1]. Dementia and pain results remain uncertain because the best-quality reviews reach different conclusions [6][9].

Go deeper

  • Aromatherapy — Inhaling essential oils may modestly improve sleep, anxiety and low mood, and sleep is the most consistent finding.
  • Sleep — Expert panels advise 7 to 9 hours of sleep a night for adults.

References

  1. Inhalation aromatherapy for the treatment of comorbid insomnia: a systematic review and meta-analysis.. Front Psychiatry, 2025.
  2. A systematic literature review and meta-analysis of the clinical effects of aroma inhalation therapy on sleep problems.. Medicine (Baltimore), 2021.
  3. Effect of aromatherapy on sleep quality of adults and elderly people: A systematic literature review and meta-analysis.. Complement Ther Med, 2021.
  4. Effects of aromatherapy on sleep quality in older adults: A meta-analysis.. Medicine (Baltimore), 2024.
  5. Effects of aromatherapy on sleep quality in hospitalized cardiac patients: A systematic review and meta-analysis of randomized controlled trials.. Complement Ther Med, 2025.
  6. Aromatherapy for dementia.. Cochrane Database Syst Rev, 2020.
  7. Efficacy of Aromatherapy Against Behavioral and Psychological Disturbances in People With Dementia: A Meta-Analysis of Randomized Controlled Trials.. J Am Med Dir Assoc, 2024.
  8. Effects of aromatherapy on agitation and aggression in cognitive impairment: A meta-analysis.. J Clin Nurs, 2025.
  9. Effects of Aromatherapy on Quality Of Life and Pain In Patients With Cancer: A Meta-Analysis.. J Pain Symptom Manage, 2024.
  10. Essential Oils, Part IV: Contact Allergy.. Dermatitis, 2016.
  11. Camphor Oil Toxicity: A Case Report.. Cureus, 2023.
  12. Effects of aromatherapy on anxiety: A meta-analysis of randomized controlled trials.. J Affect Disord, 2020.
  13. The effectiveness of aromatherapy on preoperative anxiety in adults: A systematic review and meta-analysis of randomized controlled trials.. Int J Nurs Stud, 2020.
  14. Effects of aromatherapy on depression: A meta-analysis of randomized controlled trials.. Gen Hosp Psychiatry, 2023.
  15. Effects of Lavender on Anxiety, Depression, and Physiological Parameters: Systematic Review and Meta-Analysis.. Asian Nurs Res (Korean Soc Nurs Sci), 2021.
  16. Labour pain control by aromatherapy: A meta-analysis of randomised controlled trials.. Women Birth, 2019.
  17. Aromatherapy for pain management in labour.. Cochrane Database Syst Rev, 2011.
  18. Effects of aromatherapy on nausea and vomiting in patients with cancer: A systematic review and meta-analysis of randomized controlled trials.. Complement Ther Clin Pract, 2024.
  19. Effects of Aromatherapy on Physical and Psychological Symptoms in Cancer Patients: A Systematic Review and Meta-analysis.. Cancer Nurs, 2026.
  20. The effects of Rosa damascene aromatherapy on mood and sleep: a systematic review and meta-analysis.. Front Public Health, 2025.
  21. Efficacy and Safety of Melaleuca alternifolia (Tea Tree) Oil for Acne-A Systematic Review and Meta-Analysis.. Phytother Res, 2026.
  22. Contact sensitization to essential oils: IVDK data of the years 2010-2019.. Contact Dermatitis, 2022.
  23. Concentrated tea tree oil toxicosis in dogs and cats: 443 cases (2002-2012).. J Am Vet Med Assoc, 2014.
  24. Essential oils, asthma, thunderstorms, and plant gases: a prospective study of respiratory response to ambient biogenic volatile organic compounds (BVOCs).. J Asthma Allergy, 2019.
  25. Vicks VapoRub induces mucin secretion, decreases ciliary beat frequency, and increases tracheal mucus transport in the ferret trachea.. Chest, 2009.