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Citrus sinensis (sweet orange peel oil)

Orange essential oil

The scent of sweet orange oil reduced anxiety in several small trials, mainly in people waiting for dental treatment, but the trials cannot hide the smell from participants and some results held only in subgroups, so the evidence is limited. On skin it is less phototoxic than bergamot in the tests we found, but it is not free of the risk: in one small human test, 1% orange oil caused a reaction in sunlight. Old or air-exposed oil can also trigger contact allergy through oxidised limonene.

Updated
30 September 2026
Oranges and curls of orange peel beside a small bottle
At a glance
Last reviewed 30 September 2026
Evidence
Limited
Best for
Dental anxiety (aroma)
Typical form & use
Diffused or inhaled; no standard dose
Onset
Same night
Safety
Oxidised oil can cause skin allergy. No interactions in our data.
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What it's used for

Evidence is rated per use. The same ingredient can be strong for one thing and traditional for another.

UseEvidenceWhat the research shows
Anxiety in dental patients (diffused scent)LimitedIn 72 patients waiting for dental treatment, diffused orange odour gave lower state anxiety, better mood and more calmness than no odour, but only in women. In 200 patients, orange or lavender odour both reduced anxiety and improved mood against no odour or music. In a 2024 cluster-randomised study of 486 dental patients, orange and other scents gave slightly lower anxiety than water (STAI 38.4 against 40.7), and the effect held only in a post-hoc subgroup of women. In 150 children having a local anaesthetic, orange oil by nebuliser or inhaler reduced anxiety compared with no aroma. No trial could blind people to a smell, so expectation may explain part of the effect.1,2,3,4
Anxiety and pain in labour (inhaled)LimitedIn 84 women in labour, inhaling 250 microlitres of sweet orange oil lowered anxiety and pain scores compared with distilled water. It was single-blind, from one group in Brazil, and we found no replication. A systematic review of 16 studies of aromatherapy in the first stage of labour, including two that used sweet orange, found mostly positive results but asked for more rigorous studies.5,10
Skin careTraditionalWe found no clinical trial of orange oil for acne, oily skin or any other skin condition. What is documented is that orange oil can be phototoxic, and can cause allergy.6,7,8
Household cleaning (d-limonene solvent)TraditionalLimonene, the main component of orange peel oil, is used as a degreasing solvent. A NIOSH investigation of workers using limonene-based degreasers found skin dryness and possible contact dermatitis, and describes limonene as a skin irritant and sensitiser. We found no study testing orange oil as a household disinfectant, so a cleaning use is about dissolving grease, not killing germs.9

How much

Ranges below are what studies used and what supplements commonly contain. They are not a recommendation for you. Start at the low end.

Labour trial
250 µL inhaled, once1,5
Against 250 µL of distilled water. The dental trials diffused the oil in a waiting room and do not give an amount.
Skin phototoxicity test
Reactions at 1% in water; none at 0.1%6,7
In five volunteers patch-tested with orange oil in water and then irradiated, reactions appeared at 1% (3 of 5 at 24 hours) and not at 0.1% or lower. A test in a skin model said the highest safe strength could not be applied directly to people.
Industry skin limit
None listed for sweet orange7
The Cosmetic Ingredient Review draft lists fragrance-industry limits for bergamot, lemon, lime, grapefruit and bitter orange oil in leave-on products for sun-exposed skin, and none for sweet orange oil.
Timing · The dental studies gave scent while patients waited before treatment. The labour trial was a single inhalation.With food? · Not applicable: the trials were of scent, not swallowed oil.How long to trial · Effects were measured within minutes to hours. If you try the oil on skin, patch-test first and avoid strong sun afterwards.

How people take it

Diffused or inhaledNo standard doseThe form used in all the anxiety trials: an electric diffuser, nebuliser or inhaler.
Diluted on skin (in a carrier oil or product)No tested dosePhototoxic in a small human test at 1%. Fresh oil, stored sealed and cool, is less likely to cause allergy than air-exposed oil.
Cleaning products with orange oil or d-limoneneVaries by productWorks as a solvent for grease. Wear gloves for strong products because limonene is an irritant and sensitiser.

Safety

Who should avoid
  • Undiluted oil on skin — limonene is an irritant and allergen
  • Old or oxidised oil on skin — oxidised limonene is a contact allergen
  • Skin use before strong sun or sunbeds — phototoxic reactions were seen at 1%
  • Swallowing the essential oil — the trials were of inhaled scent only
  • Pregnancy (skin use) and children — we found no safety data beyond inhalation trials
Known interactions
No interactions in our data. Absence of a flag is not clearance.

Questions people ask

What are the benefits of orange essential oil?

The best-supported use is the scent for anxiety, mainly in dental patients. Small trials found lower anxiety, but the smell cannot be hidden from participants and some effects held only in subgroups, so the evidence is limited. We found no trials for skin care.

Is orange essential oil phototoxic?

Less than bergamot, but not safe to assume. In a small volunteer test, orange oil at 1% in water caused reactions after light exposure in 3 of 5 people, while bergamot reacted at 0.1%. Cold-pressed orange oil did not cause a photosensitising reaction in hairless mice or pigs in older animal tests, and no fragrance-industry limit for sweet orange is listed in the review we read. Dilute it and avoid strong sun after skin use.

Can orange oil cause an allergic rash?

Yes. Orange oil is mostly limonene, which oxidises in air into hydroperoxides that are proven contact allergens; 1.6% of 6,719 patch-tested patients in Denmark reacted. Under 2.5% of dermatitis patients reacted to sweet orange oil itself at 2% in an older set of tests, but food handlers reacted to orange peel more often. Keep the oil sealed, use it fresh and patch-test.

What are the uses of orange oil for cleaning?

Its main component, d-limonene, dissolves grease and is used in industrial degreasers. We found no study that orange oil disinfects, and workers using limonene solvents reported dry skin and possible rashes, so wear gloves.

Sources

  1. Randomised trial Lehrner J, Eckersberger C, Walla P, Pötsch G, Deecke L. Ambient odor of orange in a dental office reduces anxiety and improves mood in female patients. Physiol Behav. 2000.
  2. Randomised trial Lehrner J, Marwinski G, Lehr S, Johren P, Deecke L. Ambient odors of orange and lavender reduce anxiety and improve mood in a dental office. Physiol Behav. 2005.
  3. Cluster-randomised trial Czakert J, Kandil FI, Boujnah H, et al. Scenting serenity: influence of essential-oil vaporization on dental anxiety - a cluster-randomized, controlled, single-blinded study (AROMA_dent). Sci Rep. 2024.
  4. Randomised trial Nirmala K, Kamatham R. Effect of Aromatherapy on Dental Anxiety and Pain in Children Undergoing Local Anesthetic Administrations: A Randomized Clinical Trial. J Caring Sci. 2021.
  5. Randomised trial Nascimento JC, Gonçalves VSDS, Souza BRS, et al. Effectiveness of aromatherapy with sweet orange oil (Citrus sinensis L.) in relieving pain and anxiety during labor. Explore (NY). 2025.
  6. Laboratory and human patch study Kejlová K, Jírová D, Bendová H, Gajdoš P, Kolářová H. Phototoxicity of essential oils intended for cosmetic use. Toxicol In Vitro. 2010.
  7. Safety assessment (industry panel, draft) Cosmetic Ingredient Review. Safety Assessment of Citrus-Derived Ingredients as Used in Cosmetics: Scientific Literature Review for Public Comment. 2013.
  8. Patch-test study Botvid S, Søgaard R, Schwensen JFB, Johansen JD. Ten Years of Patch Testing to Hydroperoxides of Limonene and Linalool: Prevalence, Patterns and Clinical Insights. Contact Dermatitis. 2026.
  9. Occupational health evaluation NIOSH. Health Hazard Evaluation Report HETA 92-0101-2341, Robins Air Force Base, Warner Robins, Georgia (d-limonene-based cleaning solvents). 1993.
  10. Systematic review Ghiasi A, Bagheri L, Haseli A. A Systematic Review on the Anxiolytic Effect of Aromatherapy during the First Stage of Labor. J Caring Sci. 2019.

Reader notes

Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.

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Last reviewed 30 September 2026 · Next review March 2027 · How we rate evidence