Essential Oils vs Carrier Oils
How essential oils and carrier oils differ, why sources describe diluting one in the other, how trials use a carrier oil as the comparison, and where no evidence was found.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read essential oil safety before you use anything on this page.
The documented differences
The sources we read describe essential oils in more detail than carrier oils. Where a source did not cover a point, the table says so.| Question | Essential oil | Carrier oil |
|---|---|---|
| What is it? | A concentrated plant extract that keeps the natural smell of its source. [1] | A plant oil used to dilute an essential oil, as in aromatherapy massage. [2] |
| How concentrated? | NCI says essential oils are very concentrated: about 220 pounds of lavender flowers make about 1 pound of oil. [2] | Not described in the sources we read. |
| What is in it? | Each oil has its own mix of chemicals, and the mix can vary within the same plant species. [1] | A 2024 review describes plant cosmetic oils such as coconut, olive, argan and jojoba as rich in emollients and fatty acids that hydrate the skin. [3] A 2021 review says jojoba (Simmondsia chinensis, seed [4]) oil is about 98% wax. [5] |
| Smell | The aroma fades away quickly in open air. [2] | Not described in the sources we read. |
| On the skin | Poison Control (US) says many can cause rashes, and some can be poisonous if absorbed through the skin or swallowed. [6] | Poison Control says a person can also be allergic to other ingredients in an essential oil product, labeled or unlabeled. [6] |
| As it ages | NCI says the chemical compounds can change as oils get older. [2] | Proper evidence not found in the sources we read. |
For skin evidence on the oils themselves, see jojoba oil and coconut oil. Those pages are about the plant oils on skin, not about mixing them with essential oils.
Why sources describe diluting
Poison Control says that because pure essential oils are potent, diluting them in a carrier oil is the best way to avoid a bad reaction from direct skin contact. [6] The National Association for Holistic Aromatherapy (NAHA, a US professional association, page undated) says to dilute known skin-irritant oils with an appropriate vegetable oil or other carrier. [7]Dilution is not described as a cure-all:
- Poison Control also says not all essential oils are appropriate for use on the skin, so product instructions matter. [6]
- NAHA says damaged or inflamed skin is often more permeable to essential oils and may react more. [7]
- Oils change in air. A Danish patch-test study reports that limonene and linalool, common fragrance chemicals, turn into potent allergy-causing forms on air exposure. [8] That study is about those two chemicals, not about carrier oils.
The sources we read give no single dilution figure that fits every oil and person. See dilution: what sources say and why charts differ and carrier oils explained.
What trials do with a carrier oil
In some aromatherapy trials the carrier oil is the comparison, so the trial tests what the essential oil adds.- NCI describes a trial of 103 cancer patients that compared massage with massage using Roman chamomile essential oil. [2] Two weeks later, anxiety had decreased in the essential oil group but not in the massage-only group. [2]
- A 2026 exploratory trial of 40 people compared massage with sweet almond oil alone against massage with fennel seed oil (Foeniculum vulgare Mill. [9]) at 1.6% in sweet almond oil, one session every 15 days for 2 months. [10] State anxiety scores were lower in the fennel group after the last session. [10]
Both are modest in size, hard to blind (people can smell the oil), and measure self-reported anxiety. Results from one oil, plant part and amount do not carry over to others. Evidence label: promising but limited.
Proper evidence not found: a source that ranks carrier oils for use with essential oils. We searched PubMed for essential oil and carrier oil comparisons on skin. It returned only laboratory formulation papers on tea tree oil gels.
Frequently asked questions
What is the difference between an essential oil and a carrier oil?
An essential oil is a concentrated plant extract with the smell of its source. [1] A carrier oil is a plant oil used to dilute it. [2]
Can an essential oil be used without a carrier oil?
Poison Control says diluting in a carrier oil is the best way to avoid a bad reaction from direct skin contact, and that not all essential oils are appropriate for skin. [6] Check the product label and ask a pharmacist or clinician.
Which carrier oil is best?
Proper evidence not found. We did not find a source comparing carrier oils for use with essential oils.
Is jojoba a true oil?
A 2021 review says jojoba oil is about 98% wax, mainly wax esters. [5]
Does a carrier oil make an essential oil safe to swallow?
No source we read says so. Poison Control warns that misuse of essential oils can cause serious poisoning. [6] Call Poison Help at 1-800-222-1222 after any swallowing. [6]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety points
- Poison Control says children have thin skin and immature livers, which might make them more susceptible to toxic effects than adults. [6] Ask a clinician before using an oil mixture on a baby or child.
- Poison Control says: do not use essential oils on damaged skin. [6]
- If a rash appears, Poison Control says to stop using the product and gently wash it off. [6] See patch testing and stopping a reaction.
- MedlinePlus (US) lists tree nuts among common food allergens. [11] The sources we read do not say whether nut-based oils on skin trigger reactions. A person with a nut allergy should ask an allergist or pharmacist.
- Swallowing is a separate danger. NCCIH says tea tree oil should not be swallowed and that doing so can cause confusion, unsteadiness, inability to walk and coma. [12] If someone swallows an essential oil, call Poison Help at 1-800-222-1222. [6] Call 911 for collapse, seizure or trouble breathing. See swallowing essential oils: what poison centers say.
References
- Essential Oils, National Institute of Environmental Health Sciences (NIEHS, US), reviewed March 19, 2026. Read 2026-10-23.
- Aromatherapy With Essential Oils (PDQ), Patient Version, National Cancer Institute (US). Read 2026-10-23.
- A Comprehensive Review of Plant-Based Cosmetic Oils (Virgin Coconut Oil, Olive Oil, Argan Oil, and Jojoba Oil), ACS Omega, 2024 (review; abstract read). Read 2026-10-23.
- GBIF Backbone Taxonomy name match for Simmondsia chinensis, Global Biodiversity Information Facility. Read 2026-10-23.
- Jojoba Oil: An Updated Comprehensive Review on Chemistry, Pharmaceutical Uses, and Toxicity, Polymers, 2021 (review; abstract read). Read 2026-10-23.
- Essential oils: Poisonous when misused, Poison Control (US), reviewed September 29, 2023. Read 2026-10-23.
- Safety, National Association for Holistic Aromatherapy (NAHA, US professional association); page undated. Read 2026-10-23.
- Ten Years of Patch Testing to Hydroperoxides of Limonene and Linalool, Contact Dermatitis, 2026 (abstract read). Read 2026-10-23.
- GBIF Backbone Taxonomy name match for Foeniculum vulgare, Global Biodiversity Information Facility. Read 2026-10-23.
- Effect of Aromatherapy Massage With Foeniculum vulgare Mill. Seed Essential Oil Compared to Massage on Anxiety, Well-Being, and Sleep Quality: An Exploratory Randomized Study, Health Science Reports, 2026 (trial; abstract read). Read 2026-10-23.
- Food allergy, MedlinePlus (US National Library of Medicine). Read 2026-10-23.
- Tea Tree Oil, NCCIH (NIH, US), last updated April 2025. Read 2026-10-23.