Does Hair Oil Actually Get In? Coconut vs. Argan vs. Castor | Ask Obia, Episode 4

Most hair oils never get inside your hair. A few do. Coconut and babassu oil can slip past the cuticle into the strand; argan, jojoba, grapeseed, almond and castor stay on the surface. Both jobs are useful, and the order you use them in is what makes the difference.

So in Episode 4 of Ask Obia I sort the oils into two piles, IN and ON, show you why the shape of the molecule decides which pile, and give you the order to use them in.

The drop test

Put a drop of coconut oil and a drop of argan oil on a strand and watch. One soaks in. One sits there and shines. Same strand, same amount, different molecule.

Why some oils get in: the shape of the molecule

Coconut and babassu are rich in lauric acid, a short, straight molecule. It's small enough to slip between the shingles of the cuticle, the outer layer of the strand, and into the cortex, the inside. Argan, jojoba, almond and castor are built from bigger, bulkier molecules. They don't fit through, so they stay on top.

Why "in" matters: swell and shrink

Every wash day, water rushes into the strand and it swells. As it dries, it shrinks. Swell, shrink, swell, shrink, and over time the cuticle cracks. Oil that's already inside means less water rushes in, so there's less swelling and fewer cracks. That's what a pre-shampoo oil is for.

This isn't just my opinion. In a 2003 study in the Journal of Cosmetic Science, Rele and Mohile found that coconut oil reduced protein loss from hair compared with sunflower oil and mineral oil, whether it went on before or after washing. That's the gets-in evidence.

Why "on" matters: the seal

The oils that stay on top have a different job. Once you've added water, they slow how fast it leaves, and they cut friction so strands glide past each other instead of snagging. Oil doesn't moisturize. Water does. A coating oil keeps it there.

The catch: porosity

Low porosity hair has a tightly closed cuticle, so even coconut oil may not get in. It can sit on top and go waxy. Babassu is the lighter cousin: it melts at skin temperature and goes in with a little warmth, so a cap and gentle heat help. High porosity hair is the opposite. It drinks everything, so feed it, then seal it.

The order: in, water, on

1. IN: a penetrating oil, coconut or babassu, on damp hair or before you shampoo. Twenty minutes under a cap.
2. WATER: your wash and your conditioner. This is where the moisture comes from.
3. ON: a coating oil last, mid-lengths to ends, to seal.

Which bottle is which

One bottle, both jobs: the Argan Rose Hair Oil. Coconut oil is the first ingredient, so it gets in; argan is there for shine and the seal.

The babassu step: the Babassu Deep Conditioner. Babassu is coconut's lighter cousin, inside a protein-free conditioner. Cap and heat for low porosity hair. For everyday slip, the Babassu Detangling Conditioner. If your strand sagged in Episode 1's test, the Babassu Hair Therapy Mask is the protein step.

If your hair says no to coconut: the Protein-Free, Coconut-Oil-Free Hair Bundle. Babassu shares coconut's lauric acid, so if you react to coconut, try one wash first. I explain more in babassu oil for hair.

Tell me: soft, greasy or waxy?

Oil your hair tonight, and an hour later, touch it. Soft, greasy or waxy? Comment OIL in the YouTube comments with your answer and I'll tell you what it means for your hair. I read these myself, and the most-asked questions become episodes.

Chapters

• 0:00 Most hair oils never get in
• 0:23 The drop test: coconut vs. argan
• 0:34 Why some get in (the shape of the molecule)
• 0:54 Why in matters (swell and shrink)
• 1:14 Why on matters (the seal)
• 1:27 Porosity, the catch
• 2:00 The order: in, water, on
• 2:22 Soft, greasy or waxy? Comment OIL
• 2:39 Class dismissed

Quick answers

Does hair oil actually get into the hair?

Some does. Coconut and babassu oil are rich in lauric acid, a small, straight molecule that can pass the cuticle. Argan, jojoba, almond and castor oil mostly stay on the surface.

Which oil is best for a pre-shampoo treatment?

A penetrating oil like coconut or babassu, on damp hair for about twenty minutes under a cap. Oil inside the strand means less swelling when water rushes in on wash day.

Does oil moisturize hair?

No. Water moisturizes. Oil slows how fast that water leaves and cuts friction, so use a coating oil after your water and conditioner, not instead of them.

Why does coconut oil feel waxy on my hair?

Low porosity hair has a tightly closed cuticle, so coconut oil can sit on top instead of getting in. Try a lighter oil like babassu, with a little warmth from a cap.

In what order should I use hair oils?

In, water, on: a penetrating oil before you wash, then your wash and conditioner, then a coating oil on mid-lengths and ends to seal.

Start here

New to Ask Obia? Watch Episode 0, my whole story in 3½ minutes. Then Episode 1: Protein, yes or no?, Episode 2: pH changes everything and Episode 3: Lather lies.