Oil Logic
Facial Oils: Who They Help and Who They Wreck
Oils are occlusives, not humectants. That single distinction explains why they work beautifully for some skin and cause breakouts in others.
Facial oils are the most misunderstood category in skincare, mostly because “moisturise” is used to mean two different things: adding water and preventing water loss.
Oils do the second. They do not do the first.
Occlusive vs. humectant
Humectants (glycerin, hyaluronic acid, panthenol) pull water toward the skin. They add hydration.
Occlusives (petrolatum, squalane, oils, waxes) form a film that slows water loss.
Emollients (fatty acids, esters) soften and smooth.
Facial oils are occlusive and emollient. Applied to dry, dehydrated skin, they seal in nothing and can leave the surface feeling tight — because there is no water underneath to hold.
This is why the same oil can feel wonderful on one person and awful on another. It is not the oil; it is the layering.
Oils by fatty acid profile
| Oil | Dominant fatty acid | Best for | Watch out |
|---|---|---|---|
| Squalane | Similar to skin sebum | Most skin types | None notable |
| Jojoba | Wax ester | Oily, acne-prone | Few |
| Rosehip | Linoleic acid | Dry, mature, uneven tone | Oxidises quickly |
| Marula | Oleic + linoleic | Normal to dry | Moderate cost |
| Argan | Oleic + linoleic | Dry, hair too | Can be heavy |
| Coconut | Lauric (high oleic) | Body, not face | Highly comedogenic |
| Olive | Oleic | Body | Comedogenic for many |
The pattern: linoleic-acid-dominant oils tend to suit acne-prone and oily skin; oleic-acid-dominant oils suit dry skin but clog pores more readily.
Who should use one
Dry skin, especially in winter or low humidity. An oil over a hydrating serum is the most effective way to stop water loss.
Mature skin where sebum production has declined.
Anyone using retinoids whose skin cannot tolerate a heavier cream.
Not for: oily, acne-prone skin in humid conditions — an oil adds occlusion where sebum is already doing that job.
How to apply
- Hydrating layer first (serum or damp skin).
- Moisturiser.
- Two to four drops of oil pressed — not rubbed — over the face.
- In the morning, only if your skin needs it and you are not wearing heavy makeup.
Applying oil to dry skin, without anything underneath, is the most common mistake.
Storage
Oils with polyunsaturated fats — rosehip, evening primrose, borage — oxidise quickly. Buy small bottles, store them dark and cool, and replace them within six months of opening.
If an oil smells rancid or fishy, it is oxidised. Oxidised oils are pro-oxidant on skin, which is the opposite of what you want.
Bottom line
Facial oil is an occlusive. Use it on top of hydration, not instead of it. Choose linoleic-dominant for oily skin and oleic-dominant for dry, and store the delicate ones properly.
Links on this page go to retailer search results — check for the specific oil and whether the packaging is opaque.
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Frequently asked
Do facial oils moisturise?
They seal in moisture rather than adding it. Applied to dry skin they can make it feel drier; applied over a hydrating layer they prevent water loss.
Will facial oil make me break out?
It depends on the oil and your skin. High-oleic oils (coconut, olive) are comedogenic for many people; squalane, rosehip and jojoba are generally better tolerated.
Can I use facial oil instead of moisturiser?
For very dry skin in cold weather, sometimes. For most skin, a moisturiser with humectants and ceramides does more, and oil goes on top.