Carrier oils vs essential oils comes down to two things: how much of the bottle each one is, and what each one is for. A carrier oil is a plain plant oil, such as jojoba, argan or sunflower. It makes up almost all of a hair oil and decides how the blend feels: light or rich, quick to sink in or slow. An essential oil is a small, concentrated aromatic extract. It is there for scent, and it is always diluted in the carrier before it touches your skin. In our blends, all the essential oils together stay at or under 1% of the bottle.
What a carrier oil is
A carrier oil is a fixed oil: it is pressed from a seed, kernel, nut or fruit, and it does not evaporate. Leave a drop of sunflower oil on a plate and it is still there tomorrow. Most carrier oils are made of triglycerides, the same kind of fat as cooking oils. Jojoba is the well-known exception. Strictly speaking it is a liquid wax, which we cover in jojoba vs argan oil for hair.
The name describes the job. The carrier "carries" the essential oils, spreading a few drops of something concentrated through a much larger volume of something mild. In a hair oil, though, the carrier is not just a vehicle. It is the product.
What a carrier oil does in a hair oil
- Slip. It lubricates the hair, so a comb or your fingers move through it more easily.
- Shine. A thin, even film of oil reflects light more evenly than dry hair does.
- Softness. Hair feels smoother and less rough to the touch.
- Weight. Light oils disappear quickly and leave little behind. Rich oils sit on the surface longer and feel heavier.
Weight is the decision that matters most for most people. It is the reason one oil suits fine hair and another suits thick, curly hair. Our guide to light vs heavy hair oils ranks every base oil we stock from light to rich.
What an essential oil is
An essential oil is the aromatic part of a plant, usually separated by steam distillation, or pressed from citrus peel. It is volatile: it evaporates, which is why you can smell it from across a room. It is not an "oil" in the cooking sense at all. It is a mix of small fragrant molecules that happens to dissolve in oil and not in water.
Essential oils are also very concentrated. The Tisserand Institute notes that they often require hundreds of plants to make a single bottle. That concentration is the point and the problem. A few drops scent a whole blend. The same few drops on bare skin can irritate it.
Plant origin is no guarantee of gentleness. The US Food and Drug Administration puts it plainly: many plants contain materials that are irritating or likely to cause allergic reactions when applied to the skin.
Carrier oils vs essential oils, side by side
The two are easy to confuse because both are called oils and both come in small amber bottles. They behave very differently.
| Carrier oil | Essential oil | |
|---|---|---|
| Share of a hair oil | Almost all of it | A small fraction, 1% or less in our blends |
| How it is made | Pressed from seeds, kernels, nuts or fruit | Usually steam-distilled; citrus oils are pressed from the peel |
| Evaporates? | No | Yes |
| What it is for | Feel, slip, shine, softness, weight | Scent |
| Smell | Mild, nutty or none | Strong and distinct |
| Used on its own? | Yes | No: always diluted first |
| From our library | Jojoba, argan, squalane, sweet almond | Rosemary, lavender, atlas cedarwood, bergamot (FCF) |
Squalane in that list is not pressed from a plant in the usual way. It is a refined, very stable oil, usually made from olives or sugar cane. It does the same job as a carrier, so the builder lists it with the base oils.
Why essential oils are always diluted in a carrier
Skin reacts to essential oils in two ways. One is irritation: redness, stinging or itching that fades once the oil is gone. The other is sensitization, an allergic response that, once it develops, tends to come back every time you meet that material again. The Tisserand Institute's guidance on dilution makes the practical point: the same oil can be fine at a low dilution and a problem at a high one, so start low.
That is what the carrier is for. It spreads a small amount of essential oil across a large area, so no patch of skin gets a concentrated dose. It also does what water cannot. Essential oils do not dissolve in water, so a few drops in a spray bottle of water simply float, and land on your scalp undiluted.
Our practice: 1% at most, 0.5% for Gentle
In every hair blend we make, all the essential oils together are at or under 1% of the bottle. Choose Gentle and the total is 0.5%. You can pick up to four essential oils; they share that total between them rather than adding to it. Each oil also has its own limit in our library, and the builder will not let a blend go past it. Those limits are being reviewed by a cosmetic chemist before launch.
If you mix oils at home, our guide on how to dilute essential oils for hair gives drop counts for a 1 oz bottle, a patch-test method and the few oils that need extra care.
Where active oils fit
Our builder uses a third role between the two. Active oils are carrier oils too, but they go in at smaller shares because they are unusually thick, strongly scented or simply more specific in what they bring. Castor is the clearest example. It is so viscous that a little thickens a whole blend, so it is used as an accent rather than a base.
So a bottle has three layers. A base carrier, most of the volume. One or more actives, in smaller amounts. Essential oils, optional, at 1% or less. Every blend also gets a small amount of vitamin E (tocopherol) to slow oxidation.
Building a hair oil from carrier and essential oils
Start with the carrier, because it decides most of the experience.
- Choose a weight for your hair. Fine or easily weighed-down hair usually prefers a light base. Thick, coarse or curly hair can take a richer one.
- Decide how you will use it. A pre-wash oil can be richer, because it gets washed out. A few drops on dry ends after styling should be light. Our guide to pre-poo hair oil covers the wash-out method.
- Add an active if you want a particular feel. More slip, more richness, more shine.
- Add scent last, or not at all. A blend with no essential oils is complete. If your scalp is easily irritated, Gentle strength or no scent is the sensible starting point.
None of this is about scalp conditions. If you are dealing with a persistent itchy, flaky or sore scalp, or with shedding, see a dermatologist.
Start with the carrier, then decide on scent
If you would like a starting point, the five-question quiz suggests a base, actives and an optional scent from your hair type and preferences. Then open the builder and change any of it. You choose the carrier, the actives and the essential oils; we weigh each one to the gram and print the formula on your label.
FAQ
Can I put essential oils straight on my scalp?
No. Undiluted essential oils are the most common cause of skin reactions to them. Always dilute in a carrier oil first, and patch test a new blend before using it on your scalp.
Is coconut oil a carrier oil?
Yes. Virgin coconut oil and fractionated coconut oil are both carrier oils. Virgin coconut turns solid below about 24 °C (76 °F); fractionated coconut stays liquid and feels lighter.
Does a hair oil need an essential oil?
No. Essential oils are there for scent. A blend of carrier oils alone works the same way on your hair and smells only faintly of the oils themselves. Leaving scent out is a reasonable choice, especially for sensitive skin.
Are fragrance oils the same as essential oils?
No. "Fragrance oil" usually means a blended perfume, often partly or wholly synthetic. An essential oil comes from a single plant. We use only essential oils, and every one we use is named on your label.
