Natural Oils & Butters · Oil
Olive Oil
Olea europaea L. (fruit oil, extra virgin and refined) · also called Olive oil, extra virgin olive oil, virgin olive oil, refined olive oil, aceite de oliva. Not the same as olive leaf extract.
Olive oil is the oil pressed from olives. It is eaten every day around the Mediterranean and is also used on skin and in massage. As a food it has the stronger research: in the Spanish PREDIMED trial, a Mediterranean diet with extra virgin olive oil was linked to fewer heart attacks and strokes than a low-fat diet, and large cohort studies link more olive oil to lower heart disease and early death. On skin the main caution is that one trial found it weakened the adult skin barrier, and guidance advises care for babies and eczema. Patch test first, and ask a doctor before using it on a baby or on eczema.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Olive Oil
Olive oil is a fat pressed from olives, made up mostly of oleic acid. As food it is the main fat of the Mediterranean diet: a large Spanish trial linked a Mediterranean diet with extra virgin olive oil to fewer heart attacks and strokes, and cohort studies link more olive oil to lower heart disease and early death, but the evidence is mostly low certainty. On skin the research is small and mixed, one trial found it weakened the skin barrier, and babies and eczema call for caution. Its best skin use is in nursing care to help prevent pressure sores.
What it is
Olive oil is the oil pressed from the fruit of Olea europaea L., the olive tree (GBIF accepts this name; family Oleaceae). It is mostly oleic acid, an omega-9 fat, with smaller amounts of linoleic acid and plant phenols such as hydroxytyrosol and tyrosol.
Labels such as extra virgin, refined and 'light' describe how the oil was made. No source we read compared these grades on skin.
Olive oil as food: what trials and cohorts show
The strongest food evidence comes from PREDIMED, a Spanish trial of 7,447 older adults at high heart risk. After the first report was withdrawn because some people were not properly randomized, the authors re-analyzed it: a Mediterranean diet with free extra virgin olive oil had a hazard ratio of 0.69 for major heart events against a low-fat advice diet. The Cochrane review rates the evidence low for deaths and moderate for fewer strokes. The diet is a package, so the oil cannot be credited alone, and the oil was supplied by industry.
CORDIOPREV, in 1,002 people who already had heart disease, also favored a Mediterranean diet over a low-fat diet, more clearly in men than in women. Two olive oil foundations helped fund it.
Cohort studies are larger but observational. A 2022 meta-analysis found lower risk of heart disease, type 2 diabetes and death with more olive oil, and no link with cancer. A US study of 92,383 adults found lower death in the highest intake group but no clear gain over other vegetable oils. People who eat more olive oil may also live differently.
A meta-analysis of 26 trials found high-polyphenol olive oil improved blood markers of oxidation and cholesterol compared with low-polyphenol olive oil. This page gives no eating advice or amounts.
How it is used
Olive oil is cooked with, eaten raw, used in massage oils and skin products, and used as a base oil for aromatherapy. Many products sold as 'olive' skin oils are blends, so read the ingredient list for Olea europaea fruit oil.
This page gives no amounts and does not advise swallowing any oil blend. The use of olive oil as a carrier for essential oils has its own page, linked under Related as olive oil as a carrier.
Olive oil on skin: what the research shows
The best-supported skin use is preventing pressure injuries in nursing homes and hospitals, alongside routine nursing care. In 571 nursing-home residents, olive oil was not clearly worse than a hyperoxygenated fatty acid product, but there was no untreated group. A small hospital trial reported a bigger drop with olive oil, but its design is weak.
For stretch marks, one Turkish trial found benefit and three Iranian trials found none. For ear wax, a Cochrane review found no proof that any drop beats water. Everything else on skin is untested or small.
Babies and eczema
In a pilot trial of 115 healthy newborns, both olive oil and sunflower oil improved hydration but gave less improvement in skin lipid structure than no oil. The trial was not powered to show clinical effects. A 2022 review of 14 trials in newborns found only one that used olive oil.
A Cochrane review of skin care with moisturizers in the first year found it probably did not change eczema risk, and may raise the risk of food allergy (low certainty, one trial). This covers moisturizers in general, not olive oil alone. Ask a doctor or nurse before using any oil on a baby.
The NHS cradle cap page lists olive oil under things not to do, saying it may not be suitable for use on skin.
Olive oil in the ear
Advice disagrees. The NHS lists olive or almond oil drops as a self-care option for ear wax but says not to use drops if you have a hole in the eardrum, and to see a nurse if symptoms have not cleared after 5 days. A 2018 review for family doctors says olive oil drops or sprays should be avoided.
In 11 chinchillas with a perforated eardrum, olive oil caused no hearing change at 30 days, but that is a small animal study. If you have ear pain, discharge or hearing loss, see a doctor rather than trying oil.
Quality, fraud and rancidity
Reviews say olive oil is one of the foods most often adulterated for money reasons, with cheaper oils mixed in or oils mislabeled. They give no rates, and they do not cover cosmetic oils.
Olive oil also breaks down as it ages. In a lab study of eight varieties, signs of breakdown rose significantly after seven months of storage. If your oil smells different from when you bought it, throw it away. Whether aged oil is worse on skin has not been tested.
Food, skin and carrier oil are three different questions
Results for eating olive oil cannot be carried over to skin, and the other way round. A diet trial says nothing about the skin barrier, and a forearm trial says nothing about heart disease. The separate carrier-oil page covers olive oil as a base for essential oils.
At a glance
Traditional uses history, not proof
- Papers describe olive oil as the main fat of Mediterranean eating and as well known for cosmetic and culinary uses, and say natural oils are used around the world in newborn skin care and massage. These are statements in papers, not tests of benefit.
Studied for research
- Heart attacks and strokes on a Mediterranean diet with extra virgin olive oil, low (one re-analyzed trial)
- Heart disease and early death in cohort studies, low (observational)
- Type 2 diabetes risk in cohort studies, low (observational)
- Cancer, insufficient (no link in cohorts; one small breast cancer result)
- Cholesterol and oxidation markers, low
- Skin barrier in adults, mixed
- Baby skin care and massage, against (reviews and guidance advise caution)
- Eczema and very dry skin, insufficient (caution from reviews)
- Preventing pressure injuries in care settings, low
- Stretch marks in pregnancy, mixed
- Ear wax, insufficient (advice disagrees)
Main compounds
- Oleic acid (omega-9), the main fat
- Linoleic acid (omega-6)
- Hydroxytyrosol and tyrosol, plant phenols that fade as oil ages
Common forms
- Extra virgin and virgin olive oil
- Refined or 'light' olive oil
- Massage oils and creams that contain it
- Carrier base for diluted essential oils
Research links: PREDIMED re-analysis: Mediterranean diet with extra-virgin olive oil (abstract) · Cochrane review: Mediterranean-style diet and heart disease (abstract) · Olive oil and death in US adults (abstract) · Olive and sunflower oil on the adult skin barrier (abstract) · Olive oil, sunflower oil or no oil for baby skin (abstract) · NHS: cradle cap · NHS: earwax build-up · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Olea europaea
- Naming authority
- L.
- Common names
- Olive oil (English); Extra virgin olive oil (English); Aceite de oliva (Spanish)
- Family or group
- Oleaceae (the olive family)
- Classification
- Plantae > Tracheophyta > Magnoliopsida > Lamiales > Oleaceae > Olea > Olea europaea
- Native range
- Not checked in the sources read.
- Habitat
- Not checked.
- What it looks like
- Roots: Not checked.; Stems: Not checked.; Leaves: Not checked.; Flowers: Not checked.; Fruit: Olive oil is pressed from the fruit (the olive); the sources read do not describe the fruit further.
- Cultivation
- Not described in the sources read, except that oil quality varies by olive variety (a storage study compared eight Tuscan varieties).
- Harvest and processing
- Reviews of cosmetic oils say extraction methods affect yield and quality, and that mechanical pressing is simple but less efficient than newer methods. Grades such as extra virgin and refined were not compared on skin in any source read.
- Look-alikes and adulterants
- Name: Olive leaf and olive leaf extract; Note: A different part of the same tree with its own research and safety notes; see the olive leaf page.; Name: Blends sold as 'olive' skin oil; Note: Some products are mixtures with other oils or fragrance. Look for the Latin name, Olea europaea fruit oil.; Name: Other oleic-acid-rich carrier oils; Note: Sweet almond oil and avocado oil are also oleic-rich; no trial in the sources read compares them with olive oil.
- Sustainability and conservation
- Not checked.
Photographs
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| Culinary and cosmetic use, as stated in papers | A 2024 review calls olive oil well known for its cosmetic and culinary applications. An editorial calls it the most consumed edible fat in the Mediterranean basin. The papers read do not give dates or traditional skin uses. | p39524627 |
| Massage and baby care, as described in papers | Papers say natural oils are used throughout the world in newborn skin care and massage; the 2013 trial abstract says natural oils are advocated and used throughout the world in neonatal skin care. No dated history was found in the sources read. | p22995032 |
Traditional use shows how it was used. It does not show that it works or is safe today.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Oleic acid PubChem 445639 | omega-9 monounsaturated fatty acid | Fruit oil Olive oil is widely described as rich in oleic acid; a percentage was not read. | Main fat of olive oil. Reviewers suggest oleic-rich oils may add barrier damage on inflamed skin. 2 30 | Chemistry |
| Linoleic acid PubChem 5280450 | omega-6 polyunsaturated fatty acid | Fruit oil A percentage was not read. | The review of clinical studies links oils low in linoleic acid and high in oleic acid with the barrier-damage concern. 30 2 | Chemistry |
| Hydroxytyrosol PubChem 82755 | phenolic compound | Fruit oil (extra virgin and virgin) Higher in oils that resisted oxidation during storage in the storage study; amounts were not read. | A storage study links higher hydroxytyrosol and tyrosol with better resistance to oxidation. 39 | Chemistry |
| Tyrosol PubChem 10393 | phenolic compound | Fruit oil Amounts were not read. | As above. 39 | Chemistry |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Skin barrier (outer layer integrity) | Stratum corneum lipids and cohesion | In adults, 4 weeks of olive oil on the forearm reduced stratum corneum integrity and caused mild redness. Authors suggest oleic acid may cause structural damage in inflamed skin. The 2025 trial found improved hydration and more early-stage skin cells with extra virgin olive oil. The mechanism is not settled. 7 30 32 | Human data |
| Oil oxidation | Free fatty acids and peroxides | Stored olive oil shows rising free fatty acids and peroxide values, signs of breakdown. Whether aged oil acts differently on skin was not tested. 39 | Chemistry |
| Oxidation of cholesterol and blood fats | Polyphenol fraction of extra virgin olive oil | The meta-analysis authors say the polyphenol fraction may be partly responsible for the heart-protective effects of extra virgin olive oil, and found lower markers of oxidation (oxidized LDL, malondialdehyde) with high-polyphenol oil. This is a suggested link from blood-marker trials, not proof. 12 | Human data |
Absorption, metabolism and elimination
- Absorption
- Not described for skin use in the sources read. The authors of the preterm massage trial state that recent studies suggest fats are absorbed through the skin, but the trial did not measure this.
- Distribution
- Not described.
- Metabolism
- Not described.
- Elimination
- Not described.
- Bioavailability
- Not described.
Isolated compounds versus whole extracts
Olive oil eaten in a Mediterranean-style diet, olive oil on skin, olive leaf extract and pure oleic acid are different things. A result for one cannot be carried to another. Extra virgin oil (rich in polyphenols) and refined oil differ in polyphenol content; a meta-analysis compared high-polyphenol with low-polyphenol olive oil on blood markers, but no source we read compared the grades on skin.
Nutritional composition
Olive oil is mostly oleic acid, a monounsaturated fat. The NHS lists it as a source of monounsaturated fat. Large cohort studies link eating more olive oil with lower rates of heart disease, type 2 diabetes and death, but not with cancer risk; these are observational and rated mostly low to moderate. Trials such as PREDIMED test a whole Mediterranean-style diet, not the oil alone. None of this says anything about skin use.
2 mixed findings6 low certainty1 very low certainty5 not enough evidence1 evidence against
What was looked at
The 15 benefits and uses checked for Olive Oil, each with how strong the evidence is. Tap one to open it.
- Heart attacks and strokes: a Mediterranean diet with extra virgin olive oilLow certainty
- People who already have heart disease: a Mediterranean dietLow certainty
- Heart disease and early death: people who eat more olive oilLow certainty
- Type 2 diabetes risk: people who eat more olive oilLow certainty
- Cancer: no link in cohorts, one promising breast cancer resultNot enough evidence
- Cholesterol and blood markers: high-polyphenol extra virgin olive oilLow certainty
- Skin barrier and moisture in adultsMixed findings
- Baby skin care, massage and eczema preventionEvidence against
- Eczema and very dry skinNot enough evidence
- Preventing pressure injuries (bed sores) in hospital and nursing homesLow certainty
- Stretch marks in pregnancyMixed findings
- Massage to protect the birth canal opening in laborNot enough evidence
- Massage with olive oil in preterm babies and weight gainVery low certainty
- Softening ear waxNot enough evidence
- Skin irritation from radiotherapyNot enough evidence
Lab markers tracked in the studies
Oxidized LDL (a marker of cholesterol damage)Blood pressureRisk of death from any cause (olive oil eaten as food)Water loss through the skin (TEWL)Water content of the outer skin layerPressure injury rateShare of pregnant women with stretch marksDaily weight gain in preterm babies
What is Olive Oil good for?
What the research shows for each use, and how strong it is. Eating olive oil and putting it on skin are separate questions with separate evidence. The skin cautions matter as much as the benefits, so read the Safety tab first if the oil is for a baby or for eczema.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Heart attacks and strokes: a Mediterranean diet with extra virgin olive oil
Low certaintyIn the large Spanish PREDIMED trial, older adults at high heart risk who followed a Mediterranean diet with free extra virgin olive oil had fewer heart attacks, strokes and heart deaths than people told to eat less fat. The oil cannot be separated from the rest of the diet, and the trial had to be withdrawn and re-analyzed.
3 studiesMediterranean diet with extra-virgin olive oil given free to particip…
Studies, doses and limits
What the trials found
One large randomized trial (re-analyzed), one Cochrane review that covers it, and a second trial in people who already have heart disease.
Results
PREDIMED re-analysis, 7,447 people, median 4.8 years: major cardiovascular events 3.8% with the extra-virgin olive oil diet, 3.4% with a nut diet and 4.4% with a reduced-fat control diet; hazard ratio 0.69 (95% CI 0.53 to 0.91) for olive oil. The Cochrane review rates the evidence for PREDIMED as low quality for cardiovascular death (HR 0.81, 0.50 to 1.32, little or no effect) and total death (HR 1.0), but moderate quality for fewer strokes (HR 0.60, 0.45 to 0.80).
Effect sizes as reported
HR 0.69 (0.53 to 0.91) for events; HR 0.60 (0.45 to 0.80) for stroke
Why this rating
A real randomized trial with a clear result, but the original report was withdrawn after some participants were not properly randomized, the control was a reduced-fat advice diet, the tested package is a whole diet, and the Cochrane review grades most outcomes low. The olive oil was supplied by industry.
Form and dose studied
Mediterranean diet with extra-virgin olive oil given free to participants; nothing here says how much anyone should eat.
Who was studied
Adults 55 to 80 in Spain at high cardiovascular risk.
Limits
Cannot show that the oil itself did the work. Results in other countries or in younger people are not shown.
Why researchers looked
Olive oil is the main added fat of the Mediterranean diet, so it is the natural food to test.
Traditional use
Olive oil is described in papers as the main fat of the Mediterranean diet.
Proposed mechanism Authors suggestion
Not tested in these trials. Reviewers and authors point to the whole diet, not to the oil alone.
A proposed mechanism does not show that the effect happens in people.
People who already have heart disease: a Mediterranean diet
Low certaintyThe CORDIOPREV trial in 1,002 people with coronary heart disease found fewer major heart events on a Mediterranean diet than on a low-fat diet over 7 years. The effect was clearer in men than in women. The abstract does not name the oil, and two olive oil foundations helped fund the trial.
2 studiesMediterranean diet taught by dietitians; the oil is not named in the …
Studies, doses and limits
What the trials found
One single-center randomized trial.
Results
Major events in 87 people on the Mediterranean diet versus 111 on the low-fat diet; adjusted hazard ratios 0.719 to 0.753 in favor of the Mediterranean diet (for example 0.719, 95% CI 0.541 to 0.957). In men HR 0.669 (0.489 to 0.915); in 175 women no difference was found.
Effect sizes as reported
HR about 0.72 to 0.75
Why this rating
One trial at one hospital, participants knew their diet, the abstract does not name the oil, and funding includes olive oil foundations.
Form and dose studied
Mediterranean diet taught by dietitians; the oil is not named in the abstract.
Who was studied
Adults aged 20 to 75 with coronary heart disease in Cordoba, Spain; 82.5% men.
Limits
A whole-diet result. Not an olive oil trial by itself.
Why researchers looked
People who have had heart disease are at high risk, so diet is tested for prevention of a second event.
Proposed mechanism Insufficient
Not tested.
A proposed mechanism does not show that the effect happens in people.
Heart disease and early death: people who eat more olive oil
Low certaintyMany large studies that follow people for years find that those who eat more olive oil have lower rates of heart disease and early death. Because these are observational, they do not prove the oil is the reason.
4 studiesOlive oil eaten as food. This page gives no eating advice or amounts.
Studies, doses and limits
What the trials found
Two meta-analyses of cohort studies, one large US cohort pair, and an umbrella review.
Results
A 2022 meta-analysis of 24 cohorts and 3 reports from one trial found, per extra 25 g a day, cardiovascular disease risk 0.84 times as high (95% CI 0.76 to 0.94) and all-cause death 0.89 (0.85 to 0.93); only the diabetes result was consistent between studies. A 2024 meta-analysis of 30 articles (2,710,351 people) found cardiovascular death 0.77 (0.67 to 0.88) and all-cause death 0.85 (0.81 to 0.89) for higher versus lower intake, with the biggest gains at lower intakes. In 92,383 US adults followed for 28 years, the highest intake group had 0.81 times the risk of death (0.78 to 0.84), but no significant difference when olive oil was compared with other vegetable oils combined. An umbrella review rated 77% of the evidence low to moderate quality.
Effect sizes as reported
CVD RR 0.84 per 25 g a day; all-cause death RR 0.89
Why this rating
Large and consistent in direction, but observational: olive oil users may also eat and live differently, and heterogeneity was high for most outcomes. The US cohort found no clear gain over other vegetable oils.
Form and dose studied
Olive oil eaten as food. This page gives no eating advice or amounts.
Who was studied
Adults in cohort studies in Europe, the US and elsewhere.
Limits
Associations only. Does not show what olive oil does on skin.
Why researchers looked
Olive oil is the main fat in Mediterranean eating, and large cohorts allow long follow-up.
Proposed mechanism Dietary pattern
Not tested.
A proposed mechanism does not show that the effect happens in people.
Type 2 diabetes risk: people who eat more olive oil
Low certaintyIn the cohort studies pooled in a 2022 meta-analysis, people who ate more olive oil were less likely to develop type 2 diabetes. This is the one result that was consistent across studies, but it is still an association.
2 studiesOlive oil eaten as food. This page gives no eating advice or amounts.
Studies, doses and limits
What the trials found
One meta-analysis of prospective cohorts (and one report from a trial).
Results
Type 2 diabetes relative risk 0.78 (95% CI 0.69 to 0.87) per extra 25 g a day, in 680,239 people with 13,389 new cases, without evidence of heterogeneity. The umbrella review quotes a similar 22% lower risk.
Effect sizes as reported
RR 0.78 (0.69 to 0.87) per 25 g a day
Why this rating
Consistent between studies, but observational.
Form and dose studied
Olive oil eaten as food. This page gives no eating advice or amounts.
Who was studied
Adults in prospective cohorts.
Limits
Does not show olive oil prevents diabetes, and says nothing about people who already have it.
Why researchers looked
Diabetes risk is one of the outcomes looked at alongside heart disease in diet studies.
Proposed mechanism Dietary pattern
Not tested.
A proposed mechanism does not show that the effect happens in people.
Cancer: no link in cohorts, one promising breast cancer result
Not enough evidenceIn big cohort studies, eating more olive oil was not linked to the risk of cancer overall. One planned follow-up of the PREDIMED trial found fewer breast cancers with the extra virgin olive oil diet, but it was based on only 35 cases.
4 studiesOlive oil eaten as food. This page gives no eating advice or amounts.
Studies, doses and limits
What the trials found
One meta-analysis of cohorts and one secondary analysis of a trial.
Results
Meta-analysis: no significant link with cancer risk (RR 0.94, 95% CI 0.86 to 1.03, per 25 g a day; 58,892 cases). The 2024 meta-analysis also found no link with cancer incidence or mortality. PREDIMED breast cancer analysis in 4,152 women: 35 cases; hazard ratio 0.32 (0.13 to 0.79) for the extra virgin olive oil diet against control; 0.59 (0.26 to 1.35) for the nut diet. The authors say it needs to be confirmed. In the US cohorts, cancer death was lower in the highest intake group (HR 0.83, 0.78 to 0.89).
Effect sizes as reported
Cohort RR 0.94 (0.86 to 1.03); PREDIMED breast cancer HR 0.32
Why this rating
Cohorts show no link overall, the US cohorts show lower cancer death, and the one trial result is a secondary analysis of very few cases from a trial that had randomization problems.
Form and dose studied
Olive oil eaten as food. This page gives no eating advice or amounts.
Who was studied
Adults in cohorts; older women at high heart risk in PREDIMED.
Limits
No evidence olive oil prevents or treats any cancer.
Why researchers looked
Cancer is a common outcome checked in diet studies.
Proposed mechanism Dietary pattern
Not tested.
A proposed mechanism does not show that the effect happens in people.
Cholesterol and blood markers: high-polyphenol extra virgin olive oil
Low certaintyIn a meta-analysis of 26 trials, extra virgin olive oil rich in polyphenols (plant compounds) improved some blood markers compared with polyphenol-poor olive oil: signs of oxidation, total cholesterol and HDL cholesterol. These are lab markers, not heart attacks.
3 studiesOlive oil eaten as food. This page gives no eating advice or amounts.
Studies, doses and limits
What the trials found
One systematic review and meta-analysis of randomized trials; the NHS gives general guidance on fats.
Results
High-polyphenol versus low-polyphenol olive oil: malondialdehyde MD -0.07 umol/L (95% CI -0.12 to -0.02), oxidized LDL SMD -0.44 (-0.78 to -0.10), total cholesterol lower (interval -6.54 to -2.39 mg/dL), HDL cholesterol MD 2.37 mg/dL (0.41 to 5.04). Individual studies reported better inflammatory markers and blood pressure. The NHS says monounsaturated fats such as olive oil help protect the heart by maintaining HDL cholesterol while lowering LDL cholesterol.
Effect sizes as reported
oxidized LDL SMD -0.44; HDL +2.37 mg/dL
Why this rating
Mostly low to moderate risk of bias, but varied trials, high heterogeneity for some markers, and the outcomes are blood tests, not illness.
Form and dose studied
Olive oil eaten as food. This page gives no eating advice or amounts.
Who was studied
Adults in 26 trials, mostly Mediterranean populations.
Limits
Compares two kinds of olive oil, not olive oil with other fats. Longer trials in non-Mediterranean groups are needed, the authors say.
Why researchers looked
Polyphenols are one reason extra virgin oil is thought to differ from refined oil.
Proposed mechanism Authors suggestion
Authors suggest the polyphenol fraction may be partly responsible; not tested here.
A proposed mechanism does not show that the effect happens in people.
Skin barrier and moisture in adults
Mixed findingsTwo forearm trials in adults disagree. A 2013 trial found that weeks of olive oil weakened the outer skin layer and caused mild redness. A 2025 trial found that extra virgin olive oil improved skin moisture and redness in healthy adults, though petrolatum did better on water loss.
3 studiesOlive oil applied to the forearm; the 2025 trial used extra virgin ol…
Studies, doses and limits
What the trials found
Two small randomized forearm trials in adults, with opposite findings on barrier strength.
Results
Olive oil for 4 weeks significantly reduced stratum corneum integrity and caused mild redness (19 adults, with and without a history of atopic dermatitis). In 54 healthy adults, extra virgin olive oil and petrolatum both raised hydration and lowered redness and skin temperature; only petrolatum also lowered water loss.
Effect sizes as reported
No effect sizes in the abstracts.
Why this rating
Two trials with opposite findings on barrier integrity; short; different olive oils, durations and measures.
Form and dose studied
Olive oil applied to the forearm; the 2025 trial used extra virgin olive oil and the 2013 abstract does not name the grade.
Who was studied
Healthy adult volunteers, some with a history of atopic dermatitis.
Limits
Both are small and short. Neither tests eczema flares or long-term use. The 2013 trial tested adults, so it cannot show what happens in babies.
Why researchers looked
Olive oil is a common home moisturizer, and the skin barrier is the main thing a skin oil should not harm.
Traditional use
Olive oil has a long tradition as a skin and massage oil; the papers read do not date or describe it.
Proposed mechanism Human biomarker
Unsettled. Authors of the review of clinical studies suggest oleic acid, the main fat in olive oil, may upset the outer skin layer when skin is inflamed. The 2025 trial reports more early-stage skin cells with olive oil, which the authors read as faster skin renewal.
A proposed mechanism does not show that the effect happens in people.
May weaken the skin barrier with repeated use; see the Safety tab.
Baby skin care, massage and eczema prevention
Evidence againstStudies and guidelines point away from using olive oil on babies' skin. A pilot trial in newborns found less improvement in skin lipid structure with olive oil than with no oil. Reviews say it may harm the skin barrier, and an Indian pediatric guideline prefers other oils.
5 studiesOil massage on baby skin.
Studies, doses and limits
What the trials found
One small pilot trial in newborns, one trial in adults, two systematic reviews and a guideline.
Results
In 115 healthy full-term newborns, olive oil or sunflower oil twice daily for 4 weeks gave better hydration but significantly less improvement in skin lipid structure than no oil; there were no differences in water loss, pH or redness. A 2018 review found olive or sunflower oil for baby dry skin may adversely affect skin barrier function. A 2022 review of 14 trials found only one that used olive oil. An Indian Academy of Pediatrics guideline prefers sunflower, coconut or mineral oil over olive oil for massage.
Effect sizes as reported
No effect sizes in the abstracts for olive oil alone.
Why this rating
Reviewers and a guideline advise caution; the studies are small and measure skin properties, not eczema. 'Against' means the evidence points away from use, not that harm in babies is proven.
Form and dose studied
Oil massage on baby skin.
Who was studied
Newborns and young infants.
Limits
The pilot trial was not powered for clinical outcomes. No trial found tested whether olive oil causes eczema in babies.
Why researchers looked
Oil massage is a traditional baby care practice in many places, and olive oil is a common choice.
Traditional use
Oil massage is described as widespread in newborn care in the papers read.
Proposed mechanism Human biomarker
Suggested only: reviewers link oleic-acid-rich oils with extra barrier damage on inflamed or immature skin.
A proposed mechanism does not show that the effect happens in people.
Do not use on babies without asking a doctor or nurse; babies' skin and eczema risk are the main concern.
Eczema and very dry skin
Not enough evidenceNo trial of olive oil as a treatment for eczema was found. The concern runs the other way: a review of clinical studies says oils high in oleic acid, like olive oil, may add damage to inflamed skin.
3 studiesOlive oil on eczema-prone skin.
Studies, doses and limits
Results
A review of 27 clinical studies of 17 plant oils concluded that in inflamed skin, oils high in oleic acid and low in linoleic acid may cause extra damage to the outer skin layer, while non-affected skin may not react negatively. A 2025 review of basic emollients for dry skin in atopic dermatitis lists olive oil only among the ingredients searched and reports no olive-oil-specific result.
Why this rating
No olive-oil-specific trial in eczema was found. Reviews give a caution, not a measured harm in eczema.
Form and dose studied
Olive oil on eczema-prone skin.
Who was studied
People with atopic dermatitis or other inflamed skin.
Limits
The oil-by-oil results of the 27-study review are not in the abstract. The 2025 emollient review has a company funder.
Why researchers looked
People with dry or itchy skin often reach for kitchen oils.
Proposed mechanism Review authors interpretation
Suggested by reviewers: oleic acid may disturb the outer skin layer when skin is already inflamed.
A proposed mechanism does not show that the effect happens in people.
Ask a doctor or pharmacist before using any oil on eczema.
Preventing pressure injuries (bed sores) in hospital and nursing homes
Low certaintyThis is the strongest human use. In nursing homes, olive oil was not clearly worse than a standard fatty-acid product, and a small hospital trial found fewer pressure injuries with olive oil than with care alone. The trials are small or lack a no-treatment group.
4 studiesOlive oil applied to at-risk skin areas as part of routine nursing ca…
Studies, doses and limits
What the trials found
Two randomized trials and one systematic review in care settings.
Results
In 571 nursing-home residents, pressure ulcer incidence over up to 30 days was 4.18% with olive oil and 6.57% with a hyperoxygenated fatty acid product (difference -2.39%, 95% CI -6.40 to 1.56; within the non-inferiority margin). In 80 hospital patients, prevalence fell from 52.5% to 5% with olive oil plus standard care and to 22.5% with standard care alone over 7 days. A 2026 systematic review of 10 articles found olive oil and the fatty-acid product similarly effective and both safe.
Effect sizes as reported
Difference -2.39% (95% CI -6.40 to 1.56) in the larger trial.
Why this rating
Two randomized trials plus a review, but one has no no-treatment group and the other has only two clusters, a very high starting rate and a short follow-up.
Form and dose studied
Olive oil applied to at-risk skin areas as part of routine nursing care (repositioning, support surfaces).
Who was studied
Hospital patients and nursing-home residents at risk of pressure injuries.
Limits
Done under nursing care alongside other prevention. This does not show benefit for healthy skin at home.
Why researchers looked
Pressure injuries are costly, and olive oil is cheap and easy to apply.
Proposed mechanism Authors suggestion
Suggested only: the authors of the hospital trial point to the oil's fats and antioxidants. Not tested.
A proposed mechanism does not show that the effect happens in people.
Not for use on open or broken skin; this is a care-team decision.
Stretch marks in pregnancy
Mixed findingsFour randomized trials tested olive oil on the belly in pregnancy. One Turkish trial found fewer and milder stretch marks; three Iranian trials found no significant difference. A 2015 review judged olive oil not effective.
5 studiesOlive oil on the abdomen twice a day during pregnancy.
Studies, doses and limits
What the trials found
Four randomized trials with mixed results.
Results
Stretch marks occurred in 50% with olive oil versus 69.2% with no treatment (156 women, third trimester, Turkey). In Iran: 40% versus 50% (second trimester, not significant), 72% versus 60% (not significant, with a cream group; 150 completed), and no significant difference in incidence or severity (100 women).
Effect sizes as reported
50% vs 69.2% in the positive trial; the other three were not significant.
Why this rating
One positive trial against three null trials; none blinded; dropouts in one.
Form and dose studied
Olive oil on the abdomen twice a day during pregnancy.
Who was studied
First-time pregnant women.
Limits
The abstracts do not report side effects. Stretch marks have no health risk themselves, per the 2015 review.
Why researchers looked
Olive oil is a very popular home remedy for stretch marks.
Proposed mechanism Composition only
Not tested; the idea is that the oil keeps skin supple.
A proposed mechanism does not show that the effect happens in people.
Massage to protect the birth canal opening in labor
Not enough evidenceOne trial compared two oils for perineal massage in labor and found no difference in tears. The blend used was almond and olive oil with added vitamins, not olive oil alone.
1 studiesA vitamin-enriched almond and olive oil blend.
Studies, doses and limits
What the trials found
One randomized trial of a blend against jojoba oil.
Results
In 164 women there were no significant differences in tears, stitches or stitching time between an almond and olive oil blend and jojoba oil (weighted OR 0.9, 95% CI 0.3 to 2.4 for tears by oil type).
Effect sizes as reported
Weighted OR 0.9 (95% CI 0.3 to 2.4).
Why this rating
One trial, a blend rather than olive oil alone, and no no-oil group.
Form and dose studied
A vitamin-enriched almond and olive oil blend.
Who was studied
Women in the second stage of labor.
Limits
Cannot show whether any oil beats no oil.
Why researchers looked
Oils are used to try to reduce tearing at birth.
Proposed mechanism Composition only
Not tested.
A proposed mechanism does not show that the effect happens in people.
Massage with olive oil in preterm babies and weight gain
Very low certaintyOne small Iranian trial found preterm babies gained more weight with olive oil massage than with massage without oil (21 g versus 7 g a day over 10 days). It is a single, short, single-blind study.
2 studiesOlive oil massage three times a day for 15 minutes for 10 days.
Studies, doses and limits
What the trials found
One randomized trial.
Results
Average daily weight gain was 21 g with olive oil massage versus 7 g with massage without oil (P < 0.001) over 10 days.
Effect sizes as reported
21 g vs 7 g a day.
Why this rating
One short single-blind trial with group sizes missing from the abstract. It measured weight, not skin, so it does not settle the skin barrier concerns.
Form and dose studied
Olive oil massage three times a day for 15 minutes for 10 days.
Who was studied
Preterm infants.
Limits
Preterm babies need hospital-guided care. Do not copy this at home.
Why researchers looked
Nurses in some units use oil in infant massage.
Proposed mechanism Authors suggestion
The authors suggest fats are absorbed through the skin; the trial did not test this.
A proposed mechanism does not show that the effect happens in people.
Preterm babies should be handled only as the neonatal team directs.
Softening ear wax
Not enough evidenceAdvice disagrees. The NHS lists olive oil drops as a self-care option for ear wax (not if the eardrum has a hole). A 2018 family doctors' review says to avoid olive oil drops. A Cochrane review found no proof that any wax-softening drop beats water, and it did not name olive oil among its oil treatments.
4 studiesDrops in the ear; the sources do not agree on whether olive oil shoul…
Studies, doses and limits
What the trials found
No olive-oil-specific trial in the sources read.
Results
A Cochrane review of 10 trials (623 people) found no evidence that oil-based drops beat water or saline; the oil trials named other oils. In 11 chinchillas with a perforated eardrum, olive oil caused no hearing change at 30 days.
Effect sizes as reported
Active drops vs no treatment: RR 4.09 (95% CI 1.00 to 16.80), low-quality evidence.
Why this rating
Guidance disagrees and no olive-oil-specific human trial was read.
Form and dose studied
Drops in the ear; the sources do not agree on whether olive oil should be used.
Who was studied
People with blocked ears from wax.
Limits
The animal study had 11 animals. Ear problems should be checked by a clinician.
Why researchers looked
Olive oil drops are a long-standing home remedy for blocked ears.
Proposed mechanism Authors suggestion
Oils are thought to soften wax; not shown to be better than water.
A proposed mechanism does not show that the effect happens in people.
Do not use drops if the eardrum may have a hole, or if there is pain or discharge. See the Safety tab.
Skin irritation from radiotherapy
Not enough evidenceAn umbrella review abstract says topical olive oil is suggested to prevent acute radiation dermatitis. No further detail was available in the abstract.
1 studiesNot described.
Studies, doses and limits
What the trials found
Mentioned only in one umbrella review abstract.
Results
No numbers in the abstract.
Why this rating
Only a one-line mention in a review abstract; the underlying trials were not read.
Form and dose studied
Not described.
Who was studied
People having radiotherapy.
Limits
Not checked beyond the abstract.
Why researchers looked
Skin care is part of radiotherapy support.
Proposed mechanism Composition only
Not described.
A proposed mechanism does not show that the effect happens in people.
Ask the radiotherapy team before putting anything on treated skin.
Connections to the rest of health
How Olive Oil connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Heart Health | Low certainty | Heart attacks and strokes: a Mediterranean diet with extra virgin olive oil: In the large Spanish PREDIMED trial, older adults at high heart risk who followed a Mediterranean diet with free extra virgin olive oil had fewer heart attacks, strokes and heart deaths than people told to eat less fat. The oil cannot be separated from the rest of the diet, and the trial had to be withdrawn and re-analyzed. People who already have heart disease: a Mediterranean diet: The CORDIOPREV trial in 1,002 people with coronary heart disease found fewer major heart events on a Mediterranean diet than on a low-fat diet over 7 years. The effect was clearer in men than in women. The abstract does not name the oil, and two olive oil foundations helped fund the trial. | 11 31 8 12 26 | |
| Heart Health | Low certainty | Heart disease and early death: people who eat more olive oil: Many large studies that follow people for years find that those who eat more olive oil have lower rates of heart disease and early death. Because these are observational, they do not prove the oil is the reason. | 24 18 13 41 | |
| Healthy Aging | Low certainty | Heart disease and early death: people who eat more olive oil: Many large studies that follow people for years find that those who eat more olive oil have lower rates of heart disease and early death. Because these are observational, they do not prove the oil is the reason. | 24 18 13 41 | |
| Blood Sugar Balance | Low certainty | Type 2 diabetes risk: people who eat more olive oil: In the cohort studies pooled in a 2022 meta-analysis, people who ate more olive oil were less likely to develop type 2 diabetes. This is the one result that was consistent across studies, but it is still an association. | 24 41 | |
| Cancer Support | Not enough evidence | Cancer: no link in cohorts, one promising breast cancer result: In big cohort studies, eating more olive oil was not linked to the risk of cancer overall. One planned follow-up of the PREDIMED trial found fewer breast cancers with the extra virgin olive oil diet, but it was based on only 35 cases. | 24 18 38 13 | |
| Cholesterol Balance | Low certainty | Cholesterol and blood markers: high-polyphenol extra virgin olive oil: In a meta-analysis of 26 trials, extra virgin olive oil rich in polyphenols (plant compounds) improved some blood markers compared with polyphenol-poor olive oil: signs of oxidation, total cholesterol and HDL cholesterol. These are lab markers, not heart attacks. | 12 26 31 | |
| Healthy Skin | Mixed findings | Skin barrier and moisture in adults: Two forearm trials in adults disagree. A 2013 trial found that weeks of olive oil weakened the outer skin layer and caused mild redness. A 2025 trial found that extra virgin olive oil improved skin moisture and redness in healthy adults, though petrolatum did better on water loss. | 7 32 30 | |
| Healthy Skin | Evidence against | Baby skin care, massage and eczema prevention: Studies and guidelines point away from using olive oil on babies' skin. A pilot trial in newborns found less improvement in skin lipid structure with olive oil than with no oil. Reviews say it may harm the skin barrier, and an Indian pediatric guideline prefers other oils. | 5 6 3 22 19 | |
| Healthy Skin | Not enough evidence | Eczema and very dry skin: No trial of olive oil as a treatment for eczema was found. The concern runs the other way: a review of clinical studies says oils high in oleic acid, like olive oil, may add damage to inflamed skin. | 30 40 7 | |
| Healthy Skin | Low certainty | Preventing pressure injuries (bed sores) in hospital and nursing homes: This is the strongest human use. In nursing homes, olive oil was not clearly worse than a standard fatty-acid product, and a small hospital trial found fewer pressure injuries with olive oil than with care alone. The trials are small or lack a no-treatment group. | 9 4 33 41 | |
| Healthy Skin | Mixed findings | Stretch marks in pregnancy: Four randomized trials tested olive oil on the belly in pregnancy. One Turkish trial found fewer and milder stretch marks; three Iranian trials found no significant difference. A 2015 review judged olive oil not effective. | 34 35 37 36 20 | |
| Womens Wellness | Mixed findings | Stretch marks in pregnancy: Four randomized trials tested olive oil on the belly in pregnancy. One Turkish trial found fewer and milder stretch marks; three Iranian trials found no significant difference. A 2015 review judged olive oil not effective. | 34 35 37 36 20 | |
| Womens Wellness | Not enough evidence | Massage to protect the birth canal opening in labor: One trial compared two oils for perineal massage in labor and found no difference in tears. The blend used was almond and olive oil with added vitamins, not olive oil alone. | 14 | |
| Healthy Skin | Very low certainty | Massage with olive oil in preterm babies and weight gain: One small Iranian trial found preterm babies gained more weight with olive oil massage than with massage without oil (21 g versus 7 g a day over 10 days). It is a single, short, single-blind study. | 16 6 | |
| Healthy Skin | Not enough evidence | Softening ear wax: Advice disagrees. The NHS lists olive oil drops as a self-care option for ear wax (not if the eardrum has a hole). A 2018 family doctors' review says to avoid olive oil drops. A Cochrane review found no proof that any wax-softening drop beats water, and it did not name olive oil among its oil treatments. | 1 25 27 10 | |
| Healthy Skin | Not enough evidence | Skin irritation from radiotherapy: An umbrella review abstract says topical olive oil is suggested to prevent acute radiation dermatitis. No further detail was available in the abstract. | 41 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Heart and circulation | Biological association | Low certainty | Fewer heart events in a re-analyzed trial of a whole diet; cohort links to lower heart disease. Preparation or compound: Olive oil eaten as part of a Mediterranean diet |
11 24 |
| Heart Circulation | Biological association | Low certainty | Studied for: Heart attacks and strokes: a Mediterranean diet with extra virgin olive oil Studied for: People who already have heart disease: a Mediterranean diet | 11 31 8 24 18 13 41 12 26 |
| Blood Sugar Support | Biological association | Low certainty | Studied for: Type 2 diabetes risk: people who eat more olive oil | 24 41 |
| Whole Body | Biological association | Not enough evidence | Studied for: Cancer: no link in cohorts, one promising breast cancer result | 24 18 38 13 |
| Skin Hair Beauty | Biological association | Mixed findings | Studied for: Skin barrier and moisture in adults Studied for: Baby skin care, massage and eczema prevention | 7 32 30 5 6 3 22 19 40 9 4 33 41 34 35 37 36 20 14 16 |
| Integumentary System | Biological association | Not enough evidence | Studied for: Softening ear wax | 1 25 27 10 |
C. Body parts and organs
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Skin | Adverse effect or risk | Low certainty | Barrier weakening in one adult trial; rare contact allergy; extra caution on babies and eczema. Preparation or compound: Olive oil on skin |
7 15 21 30 |
| Skin | Biological association | Mixed findings | Barrier weakening in one adult trial, better hydration in another; used in care settings to prevent pressure injuries. Preparation or compound: Olive oil applied to skin |
7 32 9 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Atopic dermatitis (eczema) | Adverse effect or risk | Low certainty | Authors warn oleic-rich oils may worsen it; no trial in eczema was found. Preparation or compound: Olive oil on skin |
7 30 6 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Oxidized LDL (a marker of cholesterol damage) | Biological association | Low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 12 |
| Blood pressure | Biological association | Low certainty | Measured in trials: mixed. A lab change is not the same as a health benefit. | 31 |
| Risk of death from any cause (olive oil eaten as food) | Biological association | Low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 24 13 |
| Water loss through the skin (TEWL) | Biological association | Low certainty | Measured in trials: mixed. A lab change is not the same as a health benefit. | 32 5 |
| Water content of the outer skin layer | Biological association | Low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 32 5 |
| Pressure injury rate | Biological association | Low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 9 4 |
| Share of pregnant women with stretch marks | Biological association | Mixed findings | Measured in trials: mixed. A lab change is not the same as a health benefit. | 34 36 37 35 |
| Daily weight gain in preterm babies | Biological association | Very low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 16 |
K. Biological pathways
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Skin barrier lipid organization | Preliminary mechanism | Human | Oleic-acid-rich oils may disturb outer skin layer lipids on inflamed skin (reviewers' suggestion). | 30 5 |
| LDL oxidation | Preliminary mechanism | Human | High-polyphenol olive oil lowered oxidized LDL in a meta-analysis of trials. | 12 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Oleic acid | Biological association | Chemistry | Main fat of olive oil. Reviewers suggest oleic-rich oils may add barrier damage on inflamed skin. Preparation or compound: Fruit oil |
2 30 |
| Linoleic acid | Biological association | Chemistry | The review of clinical studies links oils low in linoleic acid and high in oleic acid with the barrier-damage concern. Preparation or compound: Fruit oil |
30 2 |
| Hydroxytyrosol | Biological association | Chemistry | A storage study links higher hydroxytyrosol and tyrosol with better resistance to oxidation. Preparation or compound: Fruit oil (extra virgin and virgin) |
39 |
| Tyrosol | Biological association | Chemistry | As above. Preparation or compound: Fruit oil |
39 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 30, 2026).
Evidence at a glance: what changed in 8 lab markers
Tap a number to show only those markers. Counts are markers, not people.
The evidence
The research centre for Olive Oil. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We read PubMed abstracts of the studies cited, the full NHS pages on fats, cradle cap and earwax, and the Poison Control page, and checked the plant name in GBIF and compounds in PubChem. Certainty ratings are the compiler's own reading. Several diet trials were funded in part by olive oil organizations, which is flagged where it applies. No study is cited that we could not verify.
Study library: every study we checked 42
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Aaron 2018 Ear drops for the removal of ear wax. Cochrane Database Syst Rev · PMID 30043448 · DOI |
Systematic review |
623 Adults and children with ear wax blocking the ear (10 trials) |
Ear drops for wax (oil-based, water-based and other) Not given here Mostly about 5 days · vs No treatment, water or saline, or other drops |
Active drops cleared wax in 22% of ears versus 5% with no treatment after 5 days in one study (low-quality evidence), but there was no evidence of a difference between active drops and water or saline, or between oil-based and non-oil drops. Adverse effects were mild. The oil-based treatments named in the abstract were triethanolamine polypeptide, almond oil, benzocaine and chlorobutanol; olive oil is not named. No proof that one wax-softening drop beats another. (RR 4.09 (95% CI 1.00 to 16.80) active versus no treatment) Methods, limits and fundingOutcomes: Complete clearance of wax; discomfort, irritation or pain Limitations: Nine of ten trials were over 15 years old and the evidence was low quality. Olive oil is not among the named oil treatments, so it says little about olive oil itself. Funding and conflicts: The PubMed record lists a US National Institutes of Health grant. Conflicts of interest are not stated in the abstract. Read: abstract |
| Abdalla 2024 A Comprehensive Review of Plant-Based Cosmetic Oils (Virgin Coconut Oil, Olive Oil, Argan Oil, and Jojoba Oil): Chemical and Biological Properties and Their Cosmeceutical Applications. ACS Omega · PMID 39524627 · DOI |
Narrative review n/a |
Review of four plant cosmetic oils (virgin coconut, olive, argan, jojoba) | Cosmetic plant oils including olive oil fruit oil Not given here |
The review describes olive oil as well known for cosmetic and culinary uses, made mainly of saturated, polyunsaturated and monounsaturated fatty acids. It describes extraction methods that affect yield and quality. Descriptive; composition and uses. Methods, limits and fundingOutcomes: Chemistry, production and cosmetic uses Limitations: A descriptive review. It does not report human trial results in the abstract. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Aksucu 2022 Effects of Topical Oils on Neonatal Skin: A Systematic Review. Adv Skin Wound Care · PMID 36409192 · DOI |
Systematic review |
5683 Neonates, mostly preterm (14 randomized trials) |
Topical oils (sunflower, coconut, almond, olive, mustard and vegetable oils) various oils Not given here Varied · vs Varied |
The review included 14 trials with a total of 5,683 neonates, most of them preterm. Only one trial used olive oil (sunflower n=8, coconut n=5, almond n=2, mustard n=1, vegetable n=1). Eleven studies concluded the oils improved skin condition and barrier function; three had equivocal, negative or mixed findings. The authors say current evidence shows potential benefit but more high-level evidence is needed. Mostly positive for other oils; olive oil had one trial. Methods, limits and fundingOutcomes: Skin barrier function and skin integrity Limitations: Results are pooled for several oils, mostly sunflower and coconut. Olive oil was tested in only one of the 14 trials, so the review says little about olive oil itself. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Almesmari 2026 Topical Application of Olive Oil in Preventing Pressure Injuries Among Hospitalized Patients with Mobility Limitations: A Cluster Randomized Trial in the United Arab Emirates. Rev Recent Clin Trials · PMID 40626528 · DOI |
Controlled trial |
80 Hospitalised patients at risk of pressure injuries with limited mobility (UAE) |
Olive oil on the skin plus standard prevention care fruit oil Not given here 7 consecutive days · vs Standard prevention care alone |
Both groups started at 52.5% pressure injury prevalence. After 7 days it fell to 5% (2 of 40) with olive oil and to 22.5% (9 of 40) with standard care alone. The authors conclude olive oil with standard care reduced pressure injuries. Prevalence 5% with olive oil versus 22.5% with care alone. Methods, limits and fundingOutcomes: Pressure injury prevalence and Braden scale scores Limitations: Very small. Only two clusters were randomized, which makes the comparison weak, and half of the patients already had a pressure injury at the start. Short follow-up. The results text itself is hard to follow (Braden score changes are reported oddly), so treat the headline figure with caution. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Cooke 2016 Olive Oil, Sunflower Oil or no Oil for Baby Dry Skin or Massage: A Pilot, Assessor-blinded, Randomized Controlled Trial (the Oil in Baby SkincaRE [OBSeRvE] Study). Acta Derm Venereol · PMID 26551528 · DOI |
Controlled trial |
115 Healthy full-term newborns, stratified by family history of atopic eczema |
Olive oil or sunflower oil on baby skin fruit oil / seed oil Not given here Twice daily for 4 weeks · vs No oil |
Both oil groups had significantly better hydration, but significantly less improvement in the structure of skin lipids than the no-oil group. There were no significant differences in TEWL, pH or redness and skin scores. The authors say the study was not powered for clinical significance and advise caution in recommending oils for neonatal skin. Hydration better with oil; lipid structure improved less than with no oil. Methods, limits and fundingOutcomes: Skin lipid structure, TEWL, hydration, pH, redness and skin scores Limitations: A feasibility pilot, not powered to show clinical effects; recruitment was 11.1% and retention 80%. It reports no eczema outcome. Funding and conflicts: The PubMed record lists the UK Department of Health as a funder. Conflicts of interest are not stated in the abstract. Read: abstract |
| Cooke 2018 Skin care for healthy babies at term: A systematic review of the evidence. Midwifery · PMID 29055852 · DOI |
Systematic review |
Healthy term babies up to 6 months old (26 papers, 16 randomized trials) | Baby skin care practices, including oils for dry skin and baby massage Not given here · vs Water or other products |
The review found some evidence that daily full-body emollient may reduce atopic eczema risk in high-risk babies, but that using olive oil or sunflower oil for baby dry skin may adversely affect skin barrier function. It found no evidence about baby massage. The authors found no difference between tested wash products and water alone. Olive and sunflower oil for dry baby skin may harm the barrier. Methods, limits and fundingOutcomes: Skin barrier and eczema risk with different baby skin care practices Limitations: Search covered 2000 to 2015, English only; outcome measures were inconsistent so meta-analysis was limited. The wording 'may adversely affect' is the reviewers' own and is based on a small number of studies. Funding and conflicts: The PubMed record lists the UK Department of Health as a funder. Conflicts of interest are not stated in the abstract. Read: abstract |
| Danby 2013 Effect of olive and sunflower seed oil on the adult skin barrier: implications for neonatal skin care. Pediatr Dermatol · PMID 22995032 · DOI |
Controlled trial |
19 Adult volunteers with and without a history of atopic dermatitis (two forearm-controlled studies) |
Olive oil on the forearm (olive oil in both studies; sunflower seed oil on the other forearm in the second) fruit oil (type not stated in abstract) Not given here 4 to 5 weeks, twice daily · vs Untreated forearm (first study); sunflower seed oil on the other forearm (second study) |
After 4 weeks, olive oil significantly reduced stratum corneum integrity and caused mild redness in volunteers with and without a history of atopic dermatitis. Sunflower seed oil kept integrity, caused no redness and improved hydration. The authors conclude olive oil damages the skin barrier and could promote or worsen atopic dermatitis, and that its use for dry skin and infant massage should be discouraged. Barrier integrity fell with olive oil; not with sunflower oil. Methods, limits and fundingOutcomes: Stratum corneum integrity and cohesion, hydration, skin pH, redness Limitations: Small (19 adults), forearm tests of a few weeks, measuring skin-surface properties rather than eczema itself. Grade of the olive oil is not given in the abstract. Adults, not infants. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract (the record lists non-US government research support). Read: abstract |
| Delgado-Lista 2022 Long-term secondary prevention of cardiovascular disease with a Mediterranean diet and a low-fat diet (CORDIOPREV): a randomised controlled trial. Lancet · PMID 35525255 · DOI |
Controlled trial |
1002 Adults aged 20 to 75 with established coronary heart disease, one hospital in Cordoba, Spain (82.5% men) |
Mediterranean diet (the abstract does not name the oil) fruit oil Not given here 7 years · vs Low-fat diet |
The main outcome occurred in 87 people on the Mediterranean diet and 111 on the low-fat diet. Adjusted hazard ratios ranged from 0.719 (95% CI 0.541 to 0.957) to 0.753 (0.568 to 0.998) in favor of the Mediterranean diet. The effect was clearer in men (HR 0.669, 0.489 to 0.915) than in the 175 women, in whom no difference was found. HR about 0.72 to 0.75 for the Mediterranean diet versus the low-fat diet (0.541 to 0.957 (lowest) and 0.568 to 0.998) Methods, limits and fundingOutcomes: Composite of major cardiovascular events (heart attack, revascularization, ischemic stroke, peripheral artery disease, cardiovascular death) Limitations: One center; participants knew their diet. It tests a whole diet, not olive oil alone. The abstract does not name the oil, so it cannot be read as an olive oil trial. Funding and conflicts: Funders named in the abstract include two olive oil foundations (Fundacion Patrimonio Comunal Olivarero; Fundacion Centro para la Excelencia en Investigacion sobre Aceite de Oliva y Salud) as well as Spanish and EU public bodies: an industry-linked funding source. Registration: NCT00924937 Read: abstract |
| Díaz-Valenzuela 2019 Effectiveness and safety of olive oil preparation for topical use in pressure ulcer prevention: Multicentre, controlled, randomised, and double-blinded clinical trial. Int Wound J · PMID 31475465 · DOI |
Controlled trial |
571 Nursing-home residents at risk of pressure ulcers (23 homes, Spain) |
Olive oil solution applied to at-risk skin areas, compared with a hyperoxygenated fatty acid compound fruit oil Not given here Every 12 hours for 30 days or until a pressure ulcer appeared · vs Hyperoxygenated fatty acid compound (not a placebo) |
Pressure ulcer incidence was 4.18% in the olive oil group and 6.57% in the comparison group (difference -2.39%, 95% CI -6.40 to 1.56), within the pre-set non-inferiority margin of 7%. The authors present this as the first evidence of effectiveness and safety of topical olive oil for preventing pressure ulcers in elderly people in institutions. Olive oil was not worse than the comparison product. (Difference -2.39% (95% CI -6.40 to 1.56)) Methods, limits and fundingOutcomes: Pressure ulcer incidence Limitations: There was no untreated or placebo group, so the trial shows olive oil was not clearly worse than another product, not that it beats doing nothing. Done alongside routine nursing care. Funding and conflicts: The PubMed record lists a regional health foundation (Junta de Andalucia) as a funder. Conflicts of interest are not stated in the abstract. Read: abstract |
| Emami 2013 Ototoxicity of olive oil in a chinchilla animal model. Laryngoscope · PMID 23616417 · DOI |
Animal research animal |
11 Chinchillas with a perforated eardrum |
Olive oil in one ear and saline in the other fruit oil Not given here 30 days of follow-up · vs Saline in the other ear |
At 30 days there was no significant change in hearing thresholds and no hair cell damage on electron microscopy. The authors conclude olive oil does not seem to cause hearing loss in chinchillas with perforated eardrums. No hearing change in 11 animals. Methods, limits and fundingOutcomes: Hearing thresholds (auditory brain response) and inner ear hair cells Limitations: Animal study, 11 animals, one-off exposure; the authors say clinical studies are required. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Estruch 2018 Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. N Engl J Med · PMID 29897866 · DOI |
Controlled trial |
7447 Adults aged 55 to 80 in Spain at high cardiovascular risk, no cardiovascular disease at the start (57% women) |
Mediterranean diet supplemented with extra-virgin olive oil (a second group got mixed nuts) fruit oil Not given here Median 4.8 years (stopped early at a prespecified interim analysis) · vs Control diet: advice to reduce dietary fat |
A major event occurred in 96 people (3.8%) in the olive oil group, 83 (3.4%) in the nuts group and 109 (4.4%) in the control group. Hazard ratio 0.69 (95% CI 0.53 to 0.91) for the Mediterranean diet with extra-virgin olive oil and 0.72 (0.54 to 0.95) for nuts, against the control diet. Results were similar after leaving out 1,588 people whose group assignment was known or suspected to have departed from the protocol. The authors withdrew their 2013 report after finding protocol deviations (some people were not randomized) and published this re-analysis. HR 0.69 for the extra-virgin olive oil diet versus the reduced-fat control diet (0.53 to 0.91) Methods, limits and fundingOutcomes: Major cardiovascular event (heart attack, stroke or death from cardiovascular causes) Limitations: The 2013 report was withdrawn because some participants were not properly randomized; this is the re-analysis. People in the olive oil group also received diet education, so the oil cannot be separated from the whole Mediterranean-style diet. The control was a reduced-fat advice diet, not usual eating. Participants were older Spanish adults at high risk. Funding and conflicts: Funded by Instituto de Salud Carlos III, the Spanish Ministry of Health and others (the abstract names these); free extra-virgin olive oil was given to the olive oil group. A 2022 paper by authors from the same network says the virgin olive oil used in the trial was supplied by Patrimonio Comunal Olivarero and Hojiblanca SA (an olive oil industry link). Registration: ISRCTN35739639 Read: abstract |
| George 2019 The effect of high-polyphenol extra virgin olive oil on cardiovascular risk factors: A systematic review and meta-analysis. Crit Rev Food Sci Nutr · PMID 29708409 · DOI |
Meta-analysis |
26 randomized trials comparing high-polyphenol with low-polyphenol olive oil | High-polyphenol extra virgin olive oil fruit oil Not given here Varied · vs Low-polyphenol olive oil |
Compared with low-polyphenol olive oil, high-polyphenol olive oil improved malondialdehyde (MD -0.07 umol/L, 95% CI -0.12 to -0.02), oxidized LDL (SMD -0.44, -0.78 to -0.10), total cholesterol (reported change 4.5 mg/dL, CI -6.54 to -2.39) and HDL cholesterol (MD 2.37 mg/dL, 0.41 to 5.04). Subgroup analyses and single studies reported additional improvements in inflammatory markers and blood pressure. Most studies had low to moderate risk of bias. The authors say longer trials in non-Mediterranean populations are needed. Lab markers moved in a favorable direction with high-polyphenol oil (See results) Methods, limits and fundingOutcomes: Markers of cardiovascular risk: oxidized LDL, malondialdehyde, total and HDL cholesterol, inflammation, blood pressure Limitations: These are blood markers, not heart attacks or strokes. It compares two kinds of olive oil with each other, not olive oil with other fats. Heterogeneity was high for malondialdehyde (I2 88%). The abstract's total cholesterol figures do not line up exactly, so we state only the direction and the interval. Funding and conflicts: Funding not stated in the abstract. Read: abstract |
| Guasch-Ferre 2022 Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among U.S. Adults. J Am Coll Cardiol · PMID 35027106 · DOI |
Cohort study |
92383 60,582 women (Nurses' Health Study, 1990-2018) and 31,801 men (Health Professionals Follow-up Study) free of cardiovascular disease or cancer at the start; 36,856 deaths over 28 years |
Olive oil intake reported on a food frequency questionnaire every 4 years fruit oil Not given here 28 years of follow-up · vs Never or rarely used olive oil |
People with the highest olive oil intake (more than half a tablespoon, or 7 g, a day) had an adjusted all-cause death hazard ratio of 0.81 (95% CI 0.78 to 0.84) compared with never or rarely users. Cardiovascular death HR 0.81 (0.75 to 0.87), cancer death 0.83 (0.78 to 0.89), neurodegenerative disease death 0.71 (0.64 to 0.78) and respiratory disease death 0.82 (0.72 to 0.93). Replacing 10 g a day of margarine, butter, mayonnaise or dairy fat with olive oil was linked to 8% to 34% lower risk of death. No significant association was seen when olive oil was compared with other vegetable oils combined. All-cause death HR 0.81 for the highest versus lowest intake (0.78 to 0.84) Methods, limits and fundingOutcomes: Total death and deaths from heart disease, cancer, neurodegenerative and respiratory disease Limitations: Observational: people who use more olive oil may also differ in diet, income and lifestyle in ways that the models cannot fully remove. US health professionals; diet from questionnaires. Funding and conflicts: Public funding named (US National Institutes of Health grants and others). One author disclosed receiving the virgin olive oil used in the PREDIMED and PREDIMED-Plus trials from olive oil companies. Read: abstract |
| Harlev 2013 Can we find the perfect oil to protect the perineum? A randomized-controlled double-blind trial. J Matern Fetal Neonatal Med · PMID 23570446 · DOI |
Controlled trial |
164 Women having a vaginal birth |
Perineal massage in the second stage of labor with a blend of almond and olive oil enriched with vitamins (not olive oil alone), compared with jojoba oil fruit oil in a blend Not given here Second stage of labor · vs Jojoba oil (liquid wax) |
There were no significant differences in tears, number of stitches or stitching time between the two oils. The authors conclude the type of oil had no effect on the perineum. No difference between two oils. (Weighted OR 0.9 (95% CI 0.3 to 2.4) for tears by oil type) Methods, limits and fundingOutcomes: Perineal tears, stitches Limitations: A vitamin-enriched almond and olive oil blend, not pure olive oil. There was no no-oil group, so it cannot show whether massage with any oil helps. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Isaksson 1999 Occupational allergic contact dermatitis from olive oil in a masseur. J Am Acad Dermatol · PMID 10426917 · DOI |
Case report |
1 A masseur with hand eczema |
Olive oil used in massage fruit oil Not given here Occupational exposure |
Patch tests with olive oil were positive and a use test was positive after 2 days; an oral test was negative. The authors say contact allergy to olive oil is rare (about 20 cases described earlier) but sensitisation occurs, and that external use of olive oil should be discouraged, at least in masseurs, under occlusion and in long-standing skin disease. A rare true allergy to olive oil on skin. Methods, limits and fundingOutcomes: Allergic contact dermatitis Limitations: A single case report from 1999 plus a count of earlier cases. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Jabraeile 2016 Effect of olive oil massage on weight gain in preterm infants: A randomized controlled clinical trial. Niger Med J · PMID 27397955 · DOI |
Controlled trial |
Preterm infants (Iran) | Massage with olive oil, compared with massage without oil fruit oil Not given here 10 days, 3 times a day for 15 minutes · vs Massage without oil |
Weight gain averaged 21 g a day with olive oil massage and 7 g a day with massage without oil (P < 0.001). The authors recommend nurses use oil in infant massage in neonatal units. 21 g a day versus 7 g a day. Methods, limits and fundingOutcomes: Daily weight gain Limitations: Single-blind, 10 days, group sizes not given in the abstract. This sits uneasily with the baby-skin-barrier findings above, and the authors' idea that oil helps by being absorbed through the skin was not tested. Needs confirmation before any weight is put on it. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Kakouri 2021 Authentication of the Botanical and Geographical Origin and Detection of Adulteration of Olive Oil Using Gas Chromatography, Infrared and Raman Spectroscopy Techniques: A Review. Foods · PMID 34359435 · DOI |
Narrative review n/a |
Review of laboratory methods for checking olive oil authenticity | Olive oil authenticity testing (infrared, Raman, gas chromatography) fruit oil Not given here |
The review says olive oil is one of the products most subject to adulteration for economic reasons, so authenticity is a concern for authorities. It describes methods that can detect adulteration and identify botanical and geographical origin. Olive oil is a frequent target of adulteration. Methods, limits and fundingOutcomes: Detection of adulteration and origin Limitations: A methods review; it gives no rates for how much of the oil on sale is adulterated. Funding and conflicts: The record lists a European regional development fund. Conflicts of interest are not stated in the abstract. Read: abstract |
| Ke 2024 Olive oil intake and cardiovascular disease, cancer, and all-cause mortality: a systematic review and dose-response meta-analysis of prospective cohort studies. Food Funct · PMID 38568797 · DOI |
Systematic review |
2710351 Adults in prospective cohort studies (eating olive oil) |
Olive oil eaten as food fruit oil Dietary intake Varied · vs Lower intake |
Higher olive oil intake was linked to lower risk of cardiovascular disease (RR 0.85, 95% CI 0.77 to 0.93), coronary heart disease (RR 0.85, 0.72 to 0.99), cardiovascular death (RR 0.77, 0.67 to 0.88) and all-cause death (RR 0.85, 0.81 to 0.89). No link with cancer incidence or death was found. Higher intake was linked to lower heart disease and death risk. (CVD RR 0.85 (0.77 to 0.93)) Methods, limits and fundingOutcomes: Cardiovascular disease, cancer, all-cause mortality Limitations: Observational cohort studies. About food, not skin use. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Kelleher 2022 Skin care interventions in infants for preventing eczema and food allergy. Cochrane Database Syst Rev · PMID 36373988 · DOI |
Systematic review |
5217 Healthy term infants up to 12 months without eczema (11 trials in meta-analyses) |
Skin care in the first year, mostly emollients (all types, not olive oil alone) Not given here 24 hours to 3 years · vs No skin care intervention or local standard care |
Skin care interventions probably do not change eczema risk by 1 to 3 years (RR 1.03, 95% CI 0.81 to 1.31; moderate certainty). They may increase IgE-mediated food allergy (RR 2.53, 95% CI 0.99 to 6.49; low certainty, one trial) and probably increase skin infection during the intervention (RR 1.33, 95% CI 1.01 to 1.75; moderate certainty). The authors conclude emollients in healthy infants are probably not effective for preventing eczema, may increase food allergy risk and probably increase skin infection risk. No eczema prevention; possible harms. (RR 1.03 (0.81 to 1.31) for eczema) Methods, limits and fundingOutcomes: Eczema, IgE-mediated food allergy, skin infection and other events Limitations: Covers moisturizers in general; the abstract does not say which trials used olive oil. Most evidence low certainty. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Korgavkar 2015 Stretch marks during pregnancy: a review of topical prevention. Br J Dermatol · PMID 25255817 · DOI |
Narrative review |
Pregnant women (review of topical stretch mark prevention) | Topical products including olive oil Not given here |
The authors find limited evidence that centella, and possibly massage with bitter almond oil, may prevent stretch marks. They state that cocoa butter and olive oil are not effective for preventing stretch marks or reducing the severity of lesions, and that reliable prevention methods are scarce. Olive oil judged not effective. Methods, limits and fundingOutcomes: Stretch mark prevention Limitations: A 2015 review; it predates the 2022 trial that found benefit. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Kränke 1997 Olive oil--contact sensitizer or irritant? Contact Dermatitis · PMID 9034680 · DOI |
Case series |
100 Eczema patients (77 women, 23 men) patch tested with fresh olive oil |
Olive oil patch tests (open test, repeated open application test, and occluded tests) fruit oil Not given here Single patch tests |
Five patients had positive reactions; only one could be classed as probably allergic. The authors conclude olive oil is very weakly irritant in general but can irritate under occlusion, and seems less than suitable for treating eczema of the lower legs with venous insufficiency. 5 of 100 eczema patients reacted; mostly irritation, not allergy. Methods, limits and fundingOutcomes: Positive skin reactions and whether they looked allergic or irritant Limitations: A 1997 patch test study in people who already had eczema, so rates may be higher than in healthy skin. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Madhu 2021 Indian Academy of Pediatrics Guidelines for Pediatric Skin Care. Indian Pediatr · PMID 33632947 |
Authoritative guidance n/a |
Newborns, infants and children (India) | Skin care practices including oil massage Not given here |
The guideline recommends oil massage and prefers massage with sunflower oil, coconut oil or mineral oil over vegetable oils such as olive oil and mustard oil, which it says have been found to be detrimental to barrier function. Guideline prefers other oils over olive oil for baby massage. Methods, limits and fundingOutcomes: Recommendations for pediatric skin care Limitations: Consensus guideline from a committee review; it is a professional society's recommendation for India, not a trial. The abstract does not list the studies it relied on for olive oil. Funding and conflicts: Not stated in the abstract. Read: abstract |
| Maestrello 2022 Nuclear magnetic resonance spectroscopy in extra virgin olive oil authentication. Compr Rev Food Sci Food Saf · PMID 35876303 · DOI |
Narrative review n/a |
Review of nuclear magnetic resonance testing of extra virgin olive oil | Extra virgin olive oil authentication fruit oil Not given here |
The review says extra virgin olive oil has become a star of the food fraud context, with fraud ranging from adulteration with cheaper oils to mislabeling. It says officially recognized analytical methods cannot unambiguously trace geographical and botanical origin, and reviews NMR as a tool. Adulteration and mislabeling are known fraud types. Methods, limits and fundingOutcomes: Detecting fraud Limitations: A methods review; it gives no rates and does not cover skin-care oils. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Martínez-González 2022 Effect of olive oil consumption on cardiovascular disease, cancer, type 2 diabetes, and all-cause mortality: A systematic review and meta-analysis. Clin Nutr · PMID 36343558 · DOI |
Systematic review |
806203 Adults in prospective cohort studies and one randomized trial (eating olive oil) |
Olive oil eaten as food, per extra 25 g a day fruit oil Dietary intake, expressed per 25 g a day in the paper Follow-up 3.7 to 28 years · vs Lower intake |
Per extra 25 g a day, the relative risk was 0.84 for cardiovascular disease (95% CI 0.76 to 0.94), 0.78 for type 2 diabetes (0.69 to 0.87) and 0.89 for all-cause mortality (0.85 to 0.93). There was no significant link with cancer risk (RR 0.94, 0.86 to 1.03). Eating more olive oil was linked to lower heart disease, diabetes and death rates. (CVD RR 0.84 (0.76 to 0.94) per 25 g/day) Methods, limits and fundingOutcomes: Cardiovascular disease, cancer, type 2 diabetes, all-cause mortality Limitations: Mostly observational cohort studies, so the link may partly reflect diet and lifestyle. About food, not skin use. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Michaudet 2018 Cerumen Impaction: Diagnosis and Management. Am Fam Physician · PMID 30277727 |
Authoritative guidance |
Adults and children with ear wax blocking the ear | Management of ear wax Not given here |
The paper says effective treatments include wax-softening agents, irrigation and manual removal. It states that cotton-tipped swabs, ear candling, and olive oil drops or sprays should be avoided. Advises avoiding olive oil ear drops. Methods, limits and fundingOutcomes: Diagnosis and treatment of impacted ear wax Limitations: A clinical review for family doctors; the abstract does not give the evidence behind the olive oil advice. It disagrees with NHS advice, which lists olive oil drops as a self-care option. Funding and conflicts: Not stated in the abstract. Read: abstract |
| NHS 2023 NHS: Different fats in food (saturated, monounsaturated and polyunsaturated), page last reviewed 14 April 2023 NHS website · Source |
Authoritative guidance n/a |
n/a | n/a Not given here |
The NHS lists olive oil among sources of monounsaturated fat and says monounsaturated fats help protect your heart by maintaining levels of 'good' HDL cholesterol while reducing 'bad' LDL cholesterol. Methods, limits and fundingOutcomes: Plain-language guidance on fats Limitations: A patient information page, not a trial. The page shows a review-due date of 14 April 2026, which has passed, so it may have been updated since we read it. Read: full-text |
| NHS 2024 NHS: Earwax build-up (page last reviewed 5 January 2024) NHS website · Source |
Authoritative guidance n/a |
n/a | n/a Not given here |
The NHS lists olive or almond oil drops as a way to treat ear wax build-up yourself, says not to use almond oil if allergic to almonds, advises not to use drops if you have a hole in the eardrum (a perforated eardrum), and says to see a nurse at the GP surgery if symptoms have not cleared after 5 days or the ear is badly blocked. Methods, limits and fundingOutcomes: Self-care advice for ear wax Limitations: A patient information page, not a trial. It disagrees with the 2018 American Family Physician review, which advises avoiding olive oil drops. Read: full-text |
| NHS 2025 NHS: Cradle cap, page last reviewed 3 October 2025 NHS website · Source |
Authoritative guidance n/a |
n/a | n/a Not given here |
In its list of things not to do, the NHS says do not use olive oil, as it may not be suitable for use on skin, and do not use peanut oil because of the allergy risk. It suggests washing with baby shampoo and using an emollient. Methods, limits and fundingOutcomes: Self-care advice for cradle cap in babies Limitations: A patient information page, not a trial. It gives a short reason only. Read: full-text |
| National Capital Poison Center 2026 Poison Control (National Capital Poison Center): Essential oils, poisonous when misused (undated) poison.org · Source |
Authoritative guidance n/a |
n/a | n/a Not given here |
Poison Control says diluting essential oils in a carrier oil is the best way to avoid a bad reaction from direct skin contact, that not all essential oils are appropriate for skin, that essential oils should not be used on damaged skin, that a rash is the most common allergic reaction and the oil should be washed off, that children have thin skin and immature livers that may make them more susceptible, and that bottles must be kept out of reach of children and pets. It does not mention olive oil. Methods, limits and fundingOutcomes: Essential oil safety on skin Limitations: A US poison center page about essential oils in general, not about olive oil. It gives no dilution figure. Read: full-text |
| Poljšak 2022 Vegetable Butters and Oils as Therapeutically and Cosmetically Active Ingredients for Dermal Use: A Review of Clinical Studies. Front Pharmacol · PMID 35548366 · DOI |
Narrative review |
27 clinical studies of 17 vegetable oils and butters on skin | Vegetable oils and butters on skin (olive oil among 17) Not given here |
The authors conclude that in inflammation-affected skin, oils high in oleic acid and low or lacking in linoleic acid may cause additional structural damage to the outer skin layer, while oils high in linoleic acid and saturated fatty acids may have positive effects. Non-affected skin may not react negatively to oils high in oleic acid. Frequency and duration of use may speed or increase negative effects. Oleic-rich oils may harm inflamed skin; healthy skin may tolerate them. Methods, limits and fundingOutcomes: Effects on non-affected skin, infant skin, psoriasis, xerosis, atopic dermatitis, striae and other uses Limitations: A narrative review. The abstract does not list results oil by oil, so it does not say how many of the studies tested olive oil. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Rees 2019 Mediterranean-style diet for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev · PMID 30864165 · DOI |
Systematic review |
12461 30 randomized trials (12,461 people randomized) of Mediterranean-style diets, in healthy adults, adults at high cardiovascular risk and people with heart disease |
Mediterranean-style diets (olive oil as the main cooking ingredient and/or tree nuts, plus plant foods) fruit oil Not given here Follow-up of 3 months or more · vs No or minimal intervention, usual care or another diet |
For primary prevention, the re-analyzed PREDIMED trial (olive oil or nuts versus a low-fat diet, 4.8 years) showed little or no effect on cardiovascular death (HR 0.81, 95% CI 0.50 to 1.32) or total death (HR 1.0, 0.81 to 1.24) in low-quality evidence, but fewer strokes (HR 0.60, 0.45 to 0.80; moderate-quality evidence). Moderate-quality evidence showed lower blood pressure in primary prevention trials against no or minimal intervention (systolic -2.99 mmHg, diastolic -2.0 mmHg). For secondary prevention the Lyon Diet Heart Study (canola margarine, not olive oil) showed lower death in low-quality evidence. Two trials reported adverse events, which were absent or minor. The authors conclude there is still uncertainty on clinical endpoints. Strokes: HR 0.60 in PREDIMED; blood pressure small falls (CVD death HR 0.81 (0.50 to 1.32); strokes HR 0.60 (0.45 to 0.80)) Methods, limits and fundingOutcomes: Heart and stroke events, deaths, blood pressure, cholesterol, adverse events Limitations: A review of Mediterranean-style diets as a whole, not of olive oil alone. Trials varied in design. Only low or moderate quality evidence on most outcomes. Funding and conflicts: Funding not given in the abstract; the conflict-of-interest statement says no author has a known conflict. Read: abstract |
| Rubio-Santoyo 2025 Effects of Extra Virgin Olive Oil and Petrolatum on Skin Barrier Function and Microtopography. J Clin Med · PMID 40649050 · DOI |
Controlled trial |
54 Healthy adult volunteers (50% female, mean age 28.57) |
Extra virgin olive oil on the inner forearm, compared with petrolatum fruit oil Not given here · vs Petrolatum on another forearm area (within-person) |
Both extra virgin olive oil and petrolatum increased skin hydration and reduced redness and skin temperature. Petrolatum also reduced TEWL, and its effects were stronger. Olive oil raised the share of early-stage corneocytes (type 1), which the authors read as faster skin renewal. The authors conclude both improved skin barrier function. Olive oil improved hydration and redness in healthy adults; petrolatum did better on water loss. Methods, limits and fundingOutcomes: Skin hydration, transepidermal water loss (TEWL), temperature, redness, skin microtopography, corneocyte types Limitations: Healthy adults only; short-term; the abstract does not give the length of treatment or numbers. It does not test babies or eczema. The finding conflicts with the 2013 forearm trial, which tested olive oil for weeks and found barrier damage. Funding and conflicts: The PubMed record lists a university research office as the funder. Conflicts of interest are not stated in the abstract. Read: abstract |
| Rus-Vega 2026 Effectiveness of Olive Oil and Hyperoxygenated Fatty Acids for the Prevention of Pressure Injuries: A Systematic Review. Adv Skin Wound Care · PMID 40853126 · DOI |
Systematic review |
Patients at risk of pressure injuries (10 articles) | Olive oil and hyperoxygenated fatty acids on skin fruit oil Not given here Varied · vs Varied |
The review of 10 articles found that both olive oil and hyperoxygenated fatty acids are effective for prevention, with no statistically significant difference between them, and that both are safe. It reports a 50% cost difference in favor of olive oil. The authors say more research is needed. Olive oil and the comparison product performed similarly. Methods, limits and fundingOutcomes: Pressure injury prevention Limitations: The abstract does not give numbers or say how many trials had an untreated comparison group. It compares products, so it cannot show how much either helps compared with nothing. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Solt Kırca 2022 Effects of Olive Oil on Striae Gravidarum in Primiparous Women: A Randomized Controlled Clinical Study. Altern Ther Health Med · PMID 34559686 |
Controlled trial |
156 First-time pregnant Turkish women in the third trimester |
Olive oil on the abdomen twice a day from the third trimester to birth fruit oil Not given here Third trimester to birth · vs No intervention |
Stretch marks occurred in 50% of the olive oil group and 69.2% of the control group. Severity scores were lower with olive oil (2 versus 4). The authors conclude olive oil was very effective in reducing severity and preventing progression. Stretch marks in 50% with olive oil versus 69.2% with no treatment. Methods, limits and fundingOutcomes: Incidence, type and severity of stretch marks (Davey severity score) Limitations: One site, no blinding is possible with an oil versus nothing, and the outcome was judged by scoring scales. It disagrees with three earlier randomized trials in Iran that found no benefit. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Registration: NCT04489901 Read: abstract |
| Soltanipoor 2012 The effect of olive oil on prevention of striae gravidarum: a randomized controlled clinical trial. Complement Ther Med · PMID 22863639 · DOI |
Controlled trial |
100 First-time pregnant women (Tehran) |
1 cc of olive oil on the abdominal skin twice a day without massage fruit oil 1 cc twice a day (as stated) Until delivery · vs No cream or oil |
Severe stretch marks were less frequent with olive oil, but there was no statistically significant difference between groups in incidence or severity. The authors say olive oil could not be recommended for preventing stretch marks. No significant difference. Methods, limits and fundingOutcomes: Stretch mark incidence and severity Limitations: Small trial; no blinding is possible against 'no treatment'. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Soltanipour 2014 The effect of olive oil and the Saj® cream in prevention of striae gravidarum: A randomized controlled clinical trial. Complement Ther Med · PMID 24731892 · DOI |
Controlled trial |
150 First-time pregnant women in the second trimester (360 enrolled, 150 completed; Tehran) |
Olive oil, compared with a cream (Saj) and no treatment fruit oil Not given here Until 38 to 40 weeks of pregnancy · vs Saj cream and no treatment |
Stretch marks occurred in 72% with olive oil, 64% with the cream and 60% with no treatment, with no significant differences in incidence or severity. The authors conclude neither olive oil nor the cream prevented stretch marks. 72% with olive oil versus 60% with nothing, not significant. Methods, limits and fundingOutcomes: Occurrence and severity of stretch marks Limitations: Many dropouts (360 enrolled, 150 completed). Not blinded for an oil versus nothing. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Taavoni 2011 Effects of olive oil on striae gravidarum in the second trimester of pregnancy. Complement Ther Clin Pract · PMID 21742284 · DOI |
Controlled trial |
Pregnant women in the second trimester | Olive oil on the abdomen twice a day fruit oil Not given here To the end of the second trimester · vs No oil |
Stretch marks occurred in 40% of women using olive oil and 50% of controls, with no significant difference. The authors say olive oil to the end of the second trimester was not effective. 40% versus 50%, not significant. Methods, limits and fundingOutcomes: Occurrence of stretch marks Limitations: The abstract does not give group sizes. Short follow-up (second trimester only). Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Toledo 2015 Mediterranean Diet and Invasive Breast Cancer Risk Among Women at High Cardiovascular Risk in the PREDIMED Trial: A Randomized Clinical Trial. JAMA Intern Med · PMID 26365989 · DOI |
Controlled trial |
4152 Women aged 60 to 80 at high cardiovascular risk and without breast cancer at the start (PREDIMED; 4,282 recruited, 4,152 analyzed) |
Mediterranean diet supplemented with extra-virgin olive oil (a second group got mixed nuts) fruit oil Not given here Median 4.8 years · vs Control diet: advice to reduce dietary fat |
There were 35 confirmed cases. Rates per 1,000 person-years were 1.1 (olive oil group), 1.8 (nuts group) and 2.9 (control). Adjusted hazard ratio against control was 0.32 (95% CI 0.13 to 0.79) for the olive oil group and 0.59 (0.26 to 1.35) for the nuts group. The authors say the results are from a secondary analysis, are based on few cases and need confirming in longer and larger studies. HR 0.32 for the extra-virgin olive oil diet group versus control (0.13 to 0.79) Methods, limits and fundingOutcomes: Confirmed new invasive breast cancer (a prespecified secondary outcome) Limitations: Only 35 cases, a secondary analysis, and the original PREDIMED trial later had protocol problems with randomization (see the 2018 re-analysis). Women only, older and at high heart risk. Funding and conflicts: Funding not stated in the abstract. Registration: ISRCTN35739639 Read: abstract |
| Vendrell Calatayud 2024 Storage effect on olive oil phenols: cultivar-specific responses. Front Nutr · PMID 39077155 · DOI |
Other n/a |
Oil from eight olive varieties grown in Tuscany, tested in the lab | Virgin olive oil stored for seven months fruit oil Not given here 7 months · vs Fresh oil |
After seven months of storage, free fatty acids and peroxide values increased significantly, which the authors read as more hydrolysis and oxidation. Varieties differed: Leccino, Moraiolo and Pendolino were less affected, Bianchera and Caninese more. Olive oil oxidises with storage; varieties differ. Methods, limits and fundingOutcomes: Free fatty acids, peroxide value and phenols Limitations: Lab chemistry of food-grade oil; it does not test skin effects of aged oil. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| Wollenberg 2025 Basic Emollients for Xerosis Cutis in Atopic Dermatitis: A Review of Clinical Studies. Int J Dermatol · PMID 40265493 · DOI |
Narrative review |
People with atopic dermatitis and dry skin (clinical studies of basic emollients) | Basic emollients, searched by ingredient (olive oil is one of about 20 ingredients searched) Not given here |
The authors say that most basic emollient formulations are safe and effective for xerosis cutis in atopic dermatitis, and that ongoing use matters. The abstract names olive oil only in the list of ingredients searched and gives no olive-oil-specific result. General emollient review; nothing specific about olive oil in the abstract. Methods, limits and fundingOutcomes: Dry skin (xerosis) in atopic dermatitis Limitations: The record lists a skin-care company (Pierre Fabre) as a funder, so industry links are possible. No olive-oil-specific finding is given in the abstract. Funding and conflicts: The PubMed record lists Les Laboratoires Pierre Fabre as a funder (industry-linked). Read: abstract |
| Zou 2025 Cardiovascular, Metabolic and Endocrine, Cancer, Mortality, Derma, and Other Outcomes of Olive Oil and Oleic Acid: An Umbrella Review. Food Sci Nutr · PMID 41142012 · DOI |
Umbrella review |
Systematic reviews of olive oil and oleic acid (19 of 741 eligible studies included) | Olive oil (eaten and on skin) and oleic acid fruit oil Not given here Varied · vs Varied |
The review says topical olive oil is suggested to prevent pressure ulcers and acute radiation dermatitis, and that only a few adverse reactions (occupational allergic contact dermatitis and lichen planus pigmentosus) have been reported. For eating it reports 22% lower type 2 diabetes risk, 18% lower cardiovascular risk, and 11% lower all-cause mortality per 25 g a day. The quality of 77% of the evidence was low to moderate, and 69% of the studies had low or critically low methodological quality. Skin use: a few suggested benefits and rare reactions. Food: associations, mostly low to moderate quality. Methods, limits and fundingOutcomes: Heart, metabolic, cancer, death and skin outcomes Limitations: An umbrella review of other reviews, mostly of low quality by its own rating. The abstract does not give details of the skin findings. Funding and conflicts: Funding and conflicts of interest are not stated in the abstract. Read: abstract |
| n/a 2026 GBIF Backbone Taxonomy: Olea europaea L. (species match API); NCBI Taxonomy id 4146 n/a · Source |
Database record n/a |
n/a | n/a Not given here |
Olea europaea L. is ACCEPTED in GBIF (key 5415040), family Oleaceae, order Lamiales. NCBI Taxonomy lists Olea europaea (common olive) as taxid 4146. Methods, limits and fundingOutcomes: Accepted name and classification Limitations: Taxonomy only. Retrieved 2026-10-25 through the GBIF and NCBI APIs. Read: database |
What we do not know yet
- What the evidence supports: low for heart outcomes in trials and cohorts, low for diabetes, insufficient for cancer, mixed for adult skin barrier and stretch marks, low for pressure injury prevention, against for baby skin care, insufficient or very low for the rest.
- No trial tests olive oil alone against another oil; PREDIMED and CORDIOPREV test whole diets.
- No trial of olive oil as an eczema treatment, or for acne, scars, wounds, hair or anti-aging claims.
- No comparison of extra virgin, refined and light olive oil on skin.
- No source read on allergy to eaten olive oil or on eating it in pregnancy; regulator statements (EMA, EFSA, Cosmetic Ingredient Review) and LiverTox were not read, and the FDA letter could not be opened.
How new research is added
New studies are found by a saved PubMed search and placed in a review queue. A person reads each one before it changes any rating or safety wording.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 8
Oxidized LDL (a marker of cholesterol damage)
Lowered in trials
LDL cholesterol that has been chemically damaged; higher levels are linked to artery disease.
Low certaintyResults and what it means
Why it was measured
Used in diet trials as an early sign of heart risk.
Statistical vs. clinical meaning
A blood marker, not a health outcome.
Safety implication
None reported.
| Study | Result | People | Product |
|---|---|---|---|
| 12 | High-polyphenol olive oil lowered oxidized LDL compared with low-polyphenol olive oil (SMD -0.44, 95% CI -0.78 to -0.10). | 26 randomized trials | High-polyphenol versus low-polyphenol olive oil |
Blood pressure
Mixed results in trials
The force of blood on artery walls.
Low certaintyResults and what it means
Why it was measured
A main risk factor for stroke and heart disease.
Statistical vs. clinical meaning
Small average changes; from a whole diet, not the oil alone.
Safety implication
None reported.
| Study | Result | People | Product |
|---|---|---|---|
| 31 | Mediterranean-style diets (olive oil and/or nuts plus plant foods) lowered blood pressure in primary prevention trials versus no or minimal intervention: systolic -2.99 mmHg, diastolic -2.0 mmHg (moderate quality). Against another diet, little or no effect on blood pressure. | 30 trials, 12,461 people | Mediterranean-style diets |
Risk of death from any cause (olive oil eaten as food)
Lowered in trials
How likely people in a study are to die during follow-up.
Low certaintyResults and what it means
Why it was measured
The broadest long-term outcome in diet studies.
Statistical vs. clinical meaning
Association from observational data.
Safety implication
None reported.
Water loss through the skin (TEWL)
Mixed results in trials
How much water escapes through the skin surface; lower numbers mean a tighter barrier.
Low certaintyResults and what it means
Why it was measured
A standard measure of skin barrier function.
Statistical vs. clinical meaning
A skin-surface measure, not a health outcome.
Safety implication
None reported.
Water content of the outer skin layer
Raised in trials
How moist the top layer of skin is, measured with a probe.
Low certaintyResults and what it means
Why it was measured
Used to judge moisturizers.
Statistical vs. clinical meaning
Short-term skin measure; oils sit on the surface and add moisture feel. Does not show a lasting skin benefit.
Safety implication
None reported.
Pressure injury rate
Lowered in trials
The share of patients who develop a pressure injury (bed sore) during the study.
Low certaintyResults and what it means
Why it was measured
A clinical outcome in care settings.
Statistical vs. clinical meaning
A real clinical outcome, but trial quality is limited.
Safety implication
None reported in the abstracts.
Share of pregnant women with stretch marks
Mixed results in trials
The percentage of women who develop visible stretch marks by the end of pregnancy.
Mixed findingsResults and what it means
Why it was measured
The main outcome in prevention trials.
Statistical vs. clinical meaning
Appearance outcome; stretch marks are not harmful.
Safety implication
None reported in the abstracts.
| Study | Result | People | Product |
|---|---|---|---|
| 34 | 50% with olive oil versus 69.2% with no intervention. | 156 first-time pregnant women | Olive oil on the abdomen twice a day |
| 36 | 72% with olive oil versus 60% with no treatment; not significant. | 150 women completed | Olive oil |
| 37 | 40% with olive oil versus 50% with no oil; not significant. | Second-trimester pregnant women | Olive oil |
Daily weight gain in preterm babies
Raised in trials
Grams gained per day by a preterm baby.
Very low certaintyResults and what it means
Why it was measured
A growth measure in the neonatal unit.
Statistical vs. clinical meaning
One short trial; needs confirmation.
Safety implication
None reported.
| Study | Result | People | Product |
|---|---|---|---|
| 16 | 21 g a day with olive oil massage versus 7 g a day with massage without oil. | Preterm infants, 10 days | Olive oil massage |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 6
- Skin: olive oil can weaken the skin barrier and may worsen eczema, especially in babies. A 2013 randomized forearm trial in 19 adults found that 4 weeks of olive oil significantly reduced the strength of the outer skin layer and caused mild redness, with or without a history of atopic dermatitis. Its authors say olive oil may promote or worsen atopic dermatitis and should be discouraged for dry skin and infant massage. A review of 27 clinical studies says oils high in oleic acid may cause extra damage to inflamed skin, while healthy skin may not react badly. A 2025 trial in 54 healthy adults found olive oil improved hydration, so the evidence is not all one way. Controlled trial 7 30 32
- Babies: reviews and a paediatric guideline advise caution. A 2018 systematic review says olive or sunflower oil for baby dry skin may adversely affect skin barrier function. A pilot trial in 115 newborns found less improvement in skin lipid structure with olive or sunflower oil than with no oil. An Indian Academy of Pediatrics guideline prefers sunflower, coconut or mineral oil over olive oil, which it says has been found detrimental to barrier function. A Cochrane review of emollients in general (not olive oil alone) found they probably do not prevent eczema, may increase food allergy risk (low certainty) and probably increase skin infection. Ask a doctor or nurse before using any oil on a baby. The NHS cradle cap page says not to use olive oil on a baby's scalp because it may not be suitable for skin. Systematic review 6 5 22 19 28
- Skin reactions are rare but real. An umbrella review says only a few adverse reactions to topical olive oil have been reported, such as occupational allergic contact dermatitis and lichen planus pigmentosus. A masseur developed true contact allergy to olive oil (a 1999 case report that counted about 20 earlier cases). In 100 eczema patients patch tested with fresh olive oil, 5 reacted and only 1 looked probably allergic; the authors call olive oil weakly irritating, with more irritation under occlusion (covered skin). They say it seems unsuitable for eczema of legs with poor vein circulation. Case report 41 15 21
- Ears: guidance disagrees, and a hole in the eardrum is a stop sign. The NHS lists olive or almond oil drops as a self-care option for blocked ears but says not to use drops if you have a hole in the eardrum. A 2018 American Family Physician review says olive oil drops or sprays should be avoided. A Cochrane review found no proof that any wax-softening drop beats water, and its named oil treatments did not include olive oil. In 11 chinchillas with a perforated eardrum, olive oil caused no hearing change at 30 days. See a nurse or doctor if wax has not cleared after 5 days, or if there is pain or discharge. Authoritative guidance 27 25 1 10
- Eating olive oil: no serious harm found in the sources read, and food results are links, not proof. Olive oil is an ordinary food. The Cochrane review of Mediterranean-style diets says the two trials that reported adverse events found them absent or minor. We found no sources on allergy to eaten olive oil, so we make no claim about it. The heart, diabetes and death findings are mostly observational, and the trial results come from whole diets. They are not a reason to stop or change prescribed medicine: ask your doctor or pharmacist. Systematic review 31 24 41
- A carrier oil does not make an unsuitable essential oil safe. Poison Control says diluting essential oils in a carrier oil is the best way to avoid a bad reaction on skin, but that not all essential oils are appropriate for skin, and that they should not be used on damaged skin. It gives no olive-specific dilution figure, and none was found in the other sources read. Keep essential oils and carrier oil blends away from children and pets. Authoritative guidance 29
Side effects 5
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Weaker outer skin layer and mild redness with repeated use on forearm skin (adults) Measured by skin tests, not by symptoms. | Seen in the 2013 trial of 19 adults; not seen in the 2025 trial of 54 healthy adults, which reported better hydration and less redness | mild Not reported in the abstract | Controlled trial 7 32 |
| Contact allergy (rash, hand eczema) from olive oil Reported in a masseur exposed at work. | Rare. A 1999 report counted about 20 earlier cases; 1 of 100 eczema patients tested looked probably allergic | mild to moderate Not reported | Case report 15 21 41 |
| Skin irritation, mainly under covered skin (occlusion) Patch tests in people who already had eczema. | 5 of 100 eczema patients had positive patch reactions, most looked irritant | mild Not reported | Case series 21 |
| Possible extra skin infection and food allergy risk from moisturising babies' skin in general Covers emollients in general, not olive oil alone. | Skin infection RR 1.33 (95% CI 1.01 to 1.75, moderate certainty); food allergy RR 2.53 (0.99 to 6.49, low certainty, one trial) | moderate Not reported | Systematic review 19 |
| Adverse events in Mediterranean-style diet trials (food) Covers whole diets, not olive oil alone. | Reported in two trials; absent or minor | mild Not reported | Systematic review 31 |
Liver
No source read describes liver injury from olive oil on skin or as a carrier. Poison Control says children's immature livers may make them more susceptible to essential oils, which is a warning about essential oils, not olive oil. LiverTox was not searched for this page. 29
How often. Not known.
This is a safety connection. It is not evidence that Olive Oil supports liver health.
Medicines and supplements 4
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Essential oils mixed into the carrier other | Olive oil dilutes essential oils and makes them easier to spread; it does not change which oils are skin-sensitising or toxic. | A carrier does not make an unsuitable essential oil suitable. Check the essential oil's own safety. | Authoritative guidance Moderate certainty 29 | Follow the essential oil's own guidance. Poison Control gives no olive-specific dilution figure. |
| Covered or occluded skin (dressings, wraps, plastic) other | Covering skin kept wet with oil can raise irritation, as the patch test authors describe. | More irritation under covering in a patch test study of eczema patients. | Case series Low certainty 21 15 | Avoid covering oiled skin unless a clinician says so. |
| Medicines used on skin or in the ear drug | Not described. | No interaction study found. | Insufficient Not enough evidence | Ask a pharmacist before mixing oils with skin creams or ear drops. |
| Medicines for blood pressure, cholesterol, diabetes or blood thinning (olive oil eaten) drug | Not described. | No interaction study was found in the sources read. | Insufficient Not enough evidence | Food results do not replace prescribed medicine. Ask a pharmacist if you plan big changes to your diet while on these medicines. |
Who should check first 6
| Situation | Advice | Evidence |
|---|---|---|
| Babies, especially with eczema, dry skin or a family history of eczema | Ask a doctor or nurse first; guidelines prefer other oils. | Authoritative guidance 22 6 5 28 |
| Eczema, inflamed or broken skin | Avoid unless a doctor says otherwise. Oleic-rich oils may add barrier damage to inflamed skin. | Narrative review 30 7 |
| A known allergy to olive oil, or eczema of the lower legs with poor vein circulation | Avoid. Contact allergy is rare but has been reported. | Case report 15 21 |
| A hole (perforation) in the eardrum, ear pain or ear discharge | Do not put drops in the ear; see a doctor. | Authoritative guidance 27 |
| Pregnancy and breastfeeding | Skin use in the stretch mark trials did not report harms in the abstracts, but those abstracts do not describe safety checks. Ask a midwife or doctor before adding essential oils. | Controlled trial 34 35 37 36 |
| Eaten olive oil in pregnancy, breastfeeding, children, kidney or liver disease or before surgery | Not covered in the sources we read, so we make no claim. Lack of evidence is not proof of safety. Ask a doctor or pharmacist. | Insufficient |
Overdose, product quality and regulators
Summary. No source read reports poisoning from olive oil itself, eaten or on skin. The serious toxicity warnings in the sources are about essential oils that may be mixed into it, especially if swallowed or used on children.
Animal. One chinchilla study found no hearing change with olive oil in the middle ear.
Human doses studied. Skin trials used small amounts for days to weeks; this page gives no amounts.
High dose or long term signals. Repeated use on forearm skin weakened the barrier in one trial. Occlusion can raise irritation.
Overdose response. Not covered. For a swallowed essential oil blend, call a poison center.
Genotoxicity. Not read.
Quality problems with olive oil are about fraud and spoilage, not about a contaminant found in skin oil. No study tested olive oil sold for skin use.
Adulteration and mislabeling. Reviews say olive oil is one of the products most subject to adulteration for money reasons, and that extra virgin olive oil has become a star of the food fraud context, with fraud from mixing in cheaper oils to mislabeling. Officially recognized methods cannot unambiguously trace where an oil came from. The reviews give no rates, and they do not cover cosmetic oils. 17 23
Rancidity and storage. In a lab study of eight olive varieties, free fatty acids and peroxide values rose significantly after seven months of storage, signs of more breakdown and oxidation; some varieties held up better than others. The study measured food-grade oil, not skin effects of aged oil. 39
Food-grade versus cosmetic-labelled oil. The sources read do not compare skin products and food olive oil or say whether cosmetic oil is checked as food. The 'extra virgin', 'refined' and 'light' grades have not been compared on skin in any source read. 2
| Body | Action | Date |
|---|---|---|
| NHS (United Kingdom) (United Kingdom) | Earwax build-up page (last reviewed 5 January 2024) lists olive or almond oil drops as a self-care option, advises not to use drops if the eardrum has a hole, and says to see a nurse if symptoms have not cleared after 5 days. source | 2024-01-05 |
| Indian Academy of Pediatrics (professional guideline) (India) | 2021 guideline prefers sunflower, coconut or mineral oil over olive oil and mustard oil for baby massage. source | 2021 |
| Poison Control (National Capital Poison Center, US) (United States) | Essential oils page says dilution in a carrier oil is the best way to avoid a bad skin reaction and that oils should not be used on damaged skin. It does not mention olive oil. source | undated |
| NHS (United Kingdom) (United Kingdom) | Cradle cap page (last reviewed 3 October 2025) lists olive oil under things not to do, saying it may not be suitable for use on skin. source | 2025-10-03 |
| NHS (United Kingdom) (United Kingdom) | Different fats page (last reviewed 14 April 2023) lists olive oil as a source of monounsaturated fat and says these fats help protect your heart by maintaining HDL cholesterol while lowering LDL cholesterol. source | 2023-04-14 |
When to get medical help
- Swelling of the face or lips, trouble breathing or widespread hives after using any oil blend: treat as an emergency and call emergency services.
- A child has swallowed an essential oil blend, even a little: call a poison center or emergency services even if they seem well.
- Ear pain, discharge, sudden hearing loss or dizziness after ear drops: stop and see a doctor.
- A rash, burning or blistering after use: stop, wash the oil off and ask a pharmacist or doctor.
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
Is olive oil good for your heart?
In a large Spanish trial, a Mediterranean diet with extra virgin olive oil had fewer heart attacks and strokes than a low-fat advice diet, and cohort studies link more olive oil to lower heart disease. The trial tests a whole diet, the cohorts are observational, and a Cochrane review rates most of the evidence low. It does not replace prescribed medicine.
What did the PREDIMED trial find?
In 7,447 older adults at high heart risk in Spain, major heart events were 3.8% with a Mediterranean diet plus extra virgin olive oil and 4.4% with a low-fat advice diet (hazard ratio 0.69). The first report was withdrawn over randomization problems and re-analyzed. The oil was supplied by industry.
Does olive oil prevent diabetes or cancer?
Is extra virgin olive oil better than refined?
Is olive oil good for skin?
Is olive oil safe for babies?
Can olive oil make eczema worse?
Does olive oil prevent stretch marks?
Can you be allergic to olive oil on the skin?
Is olive oil a safe way to clean ears?
Can olive oil be fake or go rancid?
Is it okay in pregnancy or breastfeeding?
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-30
- Last substantive update
- 2026-10-30
- How we research
- We read PubMed abstracts of the studies cited, the full NHS pages on fats, cradle cap and earwax, and the Poison Control page, and checked the plant name in GBIF and compounds in PubChem. Certainty ratings are the compiler's own reading. Several diet trials were funded in part by olive oil organizations, which is flagged where it applies. No study is cited that we could not verify.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown.
Sources 42
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Aaron K, Cooper TE, Warner L et al. Ear drops for the removal of ear wax.. Cochrane Database Syst Rev. 2018. PMID 30043448. DOI 10.1002/14651858.CD012171.pub2. (abstract)
- Abdalla S, Aroua MK, Gew LT. A Comprehensive Review of Plant-Based Cosmetic Oils (Virgin Coconut Oil, Olive Oil, Argan Oil, and Jojoba Oil): Chemical and Biological Properties and Their Cosmeceutical Applications.. ACS Omega. 2024. PMID 39524627. DOI 10.1021/acsomega.4c04277. (abstract)
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- Almesmari MMS, Ilesanmi RE, Mohamed MG. Topical Application of Olive Oil in Preventing Pressure Injuries Among Hospitalized Patients with Mobility Limitations: A Cluster Randomized Trial in the United Arab Emirates.. Rev Recent Clin Trials. 2026. PMID 40626528. DOI 10.2174/0115748871363994250624201929. (abstract)
- Cooke A, Cork MJ, Victor S et al. Olive Oil, Sunflower Oil or no Oil for Baby Dry Skin or Massage: A Pilot, Assessor-blinded, Randomized Controlled Trial (the Oil in Baby SkincaRE [OBSeRvE] Study).. Acta Derm Venereol. 2016. PMID 26551528. DOI 10.2340/00015555-2279. (abstract)
- Cooke A, Bedwell C, Campbell M et al. Skin care for healthy babies at term: A systematic review of the evidence.. Midwifery. 2018. PMID 29055852. DOI 10.1016/j.midw.2017.10.001. (abstract)
- Danby SG, AlEnezi T, Sultan A et al. Effect of olive and sunflower seed oil on the adult skin barrier: implications for neonatal skin care.. Pediatr Dermatol. 2013. PMID 22995032. DOI 10.1111/j.1525-1470.2012.01865.x. (abstract)
- Delgado-Lista J, Alcala-Diaz JF, Torres-Pena JD et al. Long-term secondary prevention of cardiovascular disease with a Mediterranean diet and a low-fat diet (CORDIOPREV): a randomised controlled trial.. Lancet. 2022. PMID 35525255. DOI 10.1016/S0140-6736(22)00122-2. (abstract)
- Díaz-Valenzuela A, García-Fernández FP, Carmona Fernández P et al. Effectiveness and safety of olive oil preparation for topical use in pressure ulcer prevention: Multicentre, controlled, randomised, and double-blinded clinical trial.. Int Wound J. 2019. PMID 31475465. DOI 10.1111/iwj.13191. (abstract)
- Emami N, Daniel SJ. Ototoxicity of olive oil in a chinchilla animal model.. Laryngoscope. 2013. PMID 23616417. DOI 10.1002/lary.24041. (abstract)
- Estruch R, Ros E, Salas-Salvado J et al; PREDIMED Study Investigators. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts.. N Engl J Med. 2018. PMID 29897866. DOI 10.1056/NEJMoa1800389. (abstract)
- George ES, Marshall S, Mayr HL et al. The effect of high-polyphenol extra virgin olive oil on cardiovascular risk factors: A systematic review and meta-analysis.. Crit Rev Food Sci Nutr. 2019. PMID 29708409. DOI 10.1080/10408398.2018.1470491. (abstract)
- Guasch-Ferre M, Li Y, Willett WC et al. Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among U.S. Adults.. J Am Coll Cardiol. 2022. PMID 35027106. DOI 10.1016/j.jacc.2021.10.041. (abstract)
- Harlev A, Pariente G, Kessous R et al. Can we find the perfect oil to protect the perineum? A randomized-controlled double-blind trial.. J Matern Fetal Neonatal Med. 2013. PMID 23570446. DOI 10.3109/14767058.2013.784261. (abstract)
- Isaksson M, Bruze M. Occupational allergic contact dermatitis from olive oil in a masseur.. J Am Acad Dermatol. 1999. PMID 10426917. DOI 10.1016/s0190-9622(99)70372-5. (abstract)
- Jabraeile M, Rasooly AS, Farshi MR et al. Effect of olive oil massage on weight gain in preterm infants: A randomized controlled clinical trial.. Niger Med J. 2016. PMID 27397955. DOI 10.4103/0300-1652.184060. (abstract)
- Kakouri E, Revelou PK, Kanakis C et al. Authentication of the Botanical and Geographical Origin and Detection of Adulteration of Olive Oil Using Gas Chromatography, Infrared and Raman Spectroscopy Techniques: A Review.. Foods. 2021. PMID 34359435. DOI 10.3390/foods10071565. (abstract)
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- NHS. NHS: Cradle cap, page last reviewed 3 October 2025. NHS website. 2025. (full-text)
- National Capital Poison Center. Poison Control (National Capital Poison Center): Essential oils, poisonous when misused (undated). poison.org. 2026. (full-text)
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- n/a. GBIF Backbone Taxonomy: Olea europaea L. (species match API); NCBI Taxonomy id 4146. n/a. 2026. (database)
Where to buy
Check the label first. Whatever you buy, look for these:
- 100% pure with no added fragrance or fillers
- Cold-pressed or unrefined if you want the most natural form
- For skin use, do a small patch test first
- Cosmetic or food grade, matched to how you will use it
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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