Can You Mix Olive Oil and Coconut Oil for Lotions? The Short Answer and the Long One

Yes. Olive oil and coconut oil mix without any trouble, and warm together into a smooth blend that spreads well on dry skin. What you have made is an anhydrous body oil or body butter. A lotion is an oil-in-water emulsion: a water phase, an oil phase, an emulsifier to hold the two together, and a preservative system to protect the water. Two oils give you none of that. The blend slows water leaving your skin. It never puts any water in.

That gap between the word and the thing is my whole job. I have spent since 2011 translating perfume counter questions into plain English, mostly variations on why the bottle says one thing and the wrist says another. In Marseille I learned to compare a citrus peel against a blotter strip before I read anyone's note list, because the list is a claim and the strip is evidence. "Lotion" is that kind of claim. So is "fresh," which has generated more follow-up questions in my inbox than any complicated French term I have ever had to explain.

I am a vocabulary person, not a dermatologist. What I can do is read a spec sheet and a standard the way I read a note list, and tell you which numbers in this discussion are real and where they come from.

What you have actually made

Perfumery has the same problem with its own nouns. Extrait, eau de parfum, eau de toilette and eau de cologne describe concentration bands, and almost everyone uses them as mood words instead. Body-care nouns drifted the same way. In a formulator's vocabulary they describe structure:

• Anhydrous means no water phase at all. Your two-oil blend qualifies.
• Body butter is anhydrous, built on fats solid at room temperature, sometimes whipped for air.
• Balm is anhydrous with wax added for hold.
• Lotion and cream are emulsions, separated mainly by how much oil and thickener they carry.

Coconut oil is solid in most kitchens and olive oil is not, so a one-to-one blend usually lands somewhere between a soft butter in winter and a pourable oil in August. That temperature swing is normal and tells you nothing about whether the batch has gone off.

Oil blend versus a water-based lotion

The comparison worth making is against the thing the searcher usually has in mind: a pump bottle of body lotion from a shop. Formula Botanica publishes a full oil-in-water emulsion built on Olivem 1000, with every percentage stated, which makes it a fair reference point rather than a guess.

| | Two-oil blend | Water added at home | Emulsified lotion | |---|---|---|---| | Water content | 0% | unmeasured, uncontrolled | 63.70% in the published Olivem 1000 formula | | Emulsifier | none | none | 5% Olivem 1000; the Hallstar sheet recommends 1.5–4% as sole emulsifier, 3–4% for higher viscosity | | Preservative | not required | required, usually absent | 1.30% in that formula; phenoxyethanol is capped at 1.0% under EU Annex V | | Measurable pH | none exists | drifts, unmonitored | measured at 5.45, against a 4.5–5.5 target | | Microbial risk | low by water activity | high | controlled and challenge-tested | | How it hydrates | slows water loss only | unpredictable | delivers water, then holds it |

Look at the middle column. That is the version of this recipe that worries me, and it is the one circulating hardest.

What each oil brings to the mixture

Trade standards define these oils by their fatty acid bands, and the two oils sit almost at opposite ends.

The International Olive Council trade standard, COI/T.15/NC No 3/Rev. 20, sets olive oil's oleic acid at 55.00–85.00% and linoleic acid at 2.50–21.00%. Codex Alimentarius CXS 210-1999 gives coconut oil 45.1–53.2% lauric acid, 16.8–21.0% myristic acid, and only 5.0–10.0% oleic with 1.0–2.5% linoleic.

Those are identity bands for trade, not a reading of the bottle in your cupboard. Cultivar, harvest, processing and batch all move the real number inside the band, and no supermarket bottle comes with a certificate of analysis. If you want the actual figure for your oil, the technical data sheet for that specific product is the only place it lives.

The composition does predict one thing reliably. Coconut oil's fatty acids are saturated, which makes it far more resistant to oxidation. Olive oil's unsaturated majority is what eventually turns.

Barrier and breakout limits

Here is where I have to hand you evidence that cuts both ways, because it does.

The most cited work on olive oil and the skin barrier is Danby and colleagues, published in Pediatric Dermatology in 2013. Nineteen adult volunteers, with and without a history of atopic dermatitis, took part in two forearm-controlled studies applying six drops of oil twice daily. In the comparison arm, four weeks of olive oil significantly reduced stratum corneum integrity and produced mild erythema, in volunteers with and without eczema history. Sunflower seed oil on the other forearm preserved integrity, caused no erythema, and improved hydration. This paper is frequently miscited to Acta Dermato-Venereologica; it ran in Pediatric Dermatology, volume 30, issue 1, pages 42–50.

The mechanism the authors proposed runs straight back to those trade standards. Olive oil's high ratio of oleic to linoleic acid is the suspect, because oleic acid is a well-documented penetration enhancer that works by disordering the lipid packing of the stratum corneum. Sunflower seed oil inverts that ratio. Coconut oil avoids the question from the other side, carrying at most 5.0–10.0% oleic acid.

The same group's later OBSeRvE trial randomised 115 healthy newborns to olive oil, sunflower oil or no oil twice daily for four weeks, reported in Acta Dermato-Venereologica in 2016. Both oil groups improved hydration, and both showed significantly less improvement in lipid lamellae structure than the babies who got nothing. Transepidermal water loss, pH and erythema showed no significant differences between groups. The authors called it a feasibility pilot and declined to draw clinical conclusions, which is the correct amount of caution for a study that size.

Coconut oil's clinical file reads better. Evangelista and colleagues ran a randomised double-blind trial of virgin coconut oil against mineral oil in 117 children with mild to moderate atopic dermatitis over eight weeks, published in the International Journal of Dermatology in 2014. Mean transepidermal water loss in the coconut oil group fell from 26.68 to 7.09, against 24.12 to 13.55 for mineral oil, with SCORAD dropping 68.23% versus 38.13%.

None of these studies tested an olive-and-coconut cosmetic blend. Nineteen adults is a small sample. The coconut trial studied paediatric eczema on the body, and says nothing about an adult face.

Which brings up the comedogenic chart. Coconut oil's rating of four out of five travels everywhere, and it originates in a rabbit ear assay on raw ingredients developed by Kligman and Mills in 1972. Draelos and DiNardo tested that assumption in the Journal of the American Academy of Dermatology in 2006, patching finished cosmetic products containing supposedly comedogenic ingredients onto the upper backs of subjects selected for their ability to form comedones, alongside positive and negative controls. Their conclusion was blunt: finished products using comedogenic ingredients are not necessarily comedogenic. Dose, formulation and the person all intervene. A number assigned to a raw material in a rabbit is not a forecast for your face.

When you add water, everything changes

Recipes that call for aloe, rosewater, brewed tea, honey or a splash of tap water are describing a different product with different obligations.

Microbiologists reach for water activity, which measures the water actually available to microorganisms rather than the amount present. ISO 29621:2017 treats products at or below 0.75 as microbiologically low risk. Your two-oil blend sits far below that line. A tablespoon of aloe puts you over it, and the standard notes that some yeasts and moulds manage growth above 0.60 anyway.

Water also creates a job for an emulsifier, and emulsifiers work inside narrow windows. Hallstar's product information sheet for Olivem 1000, a common olive-derived emulsifier, gives a recommended level of 1.5–4% in oil-in-water emulsions as the sole emulsifier, going to 3–4% for higher viscosity systems. The published formula above uses 5% against a 25% oil phase, roughly one part emulsifier to five parts oil. Guessing at that ratio is how home batches separate in the jar a week later.

Commercial lotions earn their shelf life with a challenge test. Under ISO 11930, the product is inoculated with five organisms — Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus brasiliensis — and sampled over 28 days. Criteria A requires bacteria to drop at least 3.0 log by day seven, stay down at day 14, and show no increase at day 28. C. albicans must fall at least 1.0 log by day seven. A. brasiliensis must not increase by day 14 and must fall at least 1.0 log by day 28. There is no kitchen version of this test.

Preservatives are also pH-dependent, which is why formulators measure. Lambers and colleagues measured skin surface pH on the volar forearms of 330 people for the International Journal of Cosmetic Science in 2006, finding 5.12 ± 0.56 under normal washing habits and 4.93 ± 0.45 after 24 hours without water or products, and estimated the natural value at around 4.7. Leave-on emulsions are usually steered into 4.5–5.5. That published Olivem formula came in at 5.45.

Your oil blend has no pH. Not a neutral one, not a high one. pH describes hydrogen ion activity in water, and there is no water, so the reading does not exist. Dipping a test strip into oil will give you a number and the number will be meaningless.

Body, face, and the overnight question

On body skin, an oil blend is a reasonable thing to own. It works best applied to skin still damp from the shower, where it slows the evaporation of water already there. Shins, forearms, elbows, heels.

The face is a different argument, and it is individual. Reports of congestion cluster around coconut oil on acne-prone facial skin, and the honest position is that the comedogenic chart is not the reason to be careful, while your own two-week observation is.

As for leaving olive oil on the face overnight because it is food: edibility is a gut argument. Nobody eats petrolatum, which has decades of use on compromised skin behind it. The Danby data showed measurable loss of stratum corneum integrity from four weeks of body application in people whose skin was fine to begin with, which is enough for me to keep it off eczema-prone or broken skin overnight.

A small-batch check before you commit

Contact dermatitis clinics hold patch tests under occlusion for 48 hours and read them twice, at 48 and 96 hours. Borrow the timing.

1. Melt two tablespoons total, one part coconut to one part olive, and let it cool.
2. Smell it on a strip of paper and write down what it smells like. That is your baseline.
3. Apply a small amount to the inner forearm, cover it, and leave it 48 hours.
4. Read the site at 48 hours, then again at 96 hours.
5. If it stays clear, use the blend on one limb for two weeks before committing to the whole body.
6. Spoon it out with a dry spoon and keep the jar out of the shower.

Two limits on step four. Under the ICDRG scale used in clinics, redness alone without infiltration or papules is scored doubtful rather than positive, and often turns out to be irritation. And a further reading at day seven catches roughly another 10% of allergic reactions, which is why a single 48-hour check is a screen and never a clearance for repeated use on the face.

The smell is your best instrument

This is the part I can actually claim expertise in, and it is the part every recipe leaves out.

Oxidised oil has a signature: putty, old crayons, drying wall paint, stale nuts, damp cardboard. Once you have named it on a blotter you will never miss it again, and it arrives well before anything looks wrong. Olive oil, carrying that 55.00–85.00% oleic fraction plus its linoleic share, gets there sooner than coconut oil does. A blend goes at the pace of its most vulnerable component.

Anhydrous does not mean sterile, either. ISO 29621 explicitly credits packaging that keeps microorganisms out, which is a quiet way of saying that wet fingers and steamy bathrooms undo the protection water activity gave you.

I cannot give you a shelf life for your jar. It depends on how old the oils were when you bought them, whether the container is clear or dark, how warm the room is, and how you get the product out. Smell it weekly against the note you wrote on day one. Your nose is a better sensor than any expiry date you could guess at.

Frequently asked questions

Is olive oil or coconut oil better for mature skin?

Neither has been tested head to head for mature skin. Olive oil runs 55.00–85.00% oleic acid under the International Olive Council trade standard and spreads richly; coconut oil is 45.1–53.2% lauric acid under Codex CXS 210-1999 and sets firmer. Judge by how your skin responds over two weeks rather than by the fatty acid table.

Which oils can I mix into my body lotion?

At the making stage, almost any cosmetic-grade oil works in the oil phase, which typically runs 15–25% of an emulsion. The emulsifier sets the limit, not the oil. Stirring oil into a finished shop-bought lotion is a different act: it dilutes the preservative below its tested level and can break the emulsion.

What happens if I leave olive oil on my face overnight?

In Danby's 2013 forearm study, four weeks of twice-daily olive oil significantly reduced stratum corneum integrity and produced mild erythema in adults with and without eczema history. That was body skin over weeks rather than one facial night, but it argues against assuming olive oil is gentle because it happens to be edible.

Can I mix olive oil and coconut oil for my hair instead?

Yes, and coconut oil carries the stronger evidence there. Rele and Mohile, in the Journal of Cosmetic Science in 2003, found coconut oil was the only one of three oils tested to reduce protein loss from hair, attributing it to lauric acid's small straight chain penetrating the shaft rather than sitting on top.

What turns an oil blend into a real lotion?

Three additions: a water phase, an emulsifier holding water and oil together, and a preservative system that survives a challenge test. Under ISO 11930 Criteria A, bacterial counts must fall at least 3.0 log by day seven and show no increase through day 28. Blending harder achieves none of this.

How do I patch test a new body oil before using it?

Apply a small amount to the inner forearm, cover it, and leave it 48 hours, the standard occlusion period in contact dermatitis testing. Read the site at 48 hours and again at 96 hours. Redness with no swelling or papules scores as doubtful rather than positive on the ICDRG scale.