Oils That Penetrate Vs. Coat the Hair
Disclaimer: What works for my hair may not work for your hair. And just because something you saw work wonders for someone else’s hair doesn’t mean it’ll work for your hair. When will we learn this.
The product that has helped my hair to recover while in transition, and damage from bleach, plus continues to help my hair thrive is raw oils! There is always someone trying to put down oils for hair. You cannot convince me that oils do not belong on hair, my hair is proof that it works. Is it for everyone? Absolutely NOT! Oils do NOT equal moisture. The KEY is finding the oils and amount for your OWN hair because everyone’s hair responds to it DIFFERENTLY. Oils do NOT equal moisture.
The treatments we do for our hair need to be thought of differently as those we do for our skin. Because hair is not a living system; it’s dead. It cannot respond to its environment so it's up to us to do things for our hair. However, our skin can respond and adapt.
There are oils that can and are able to penetrate the hair shaft to support moisture RETENTION. And there are some oils that only COAT the hair. Coconut oil for example, outperforms sunflower and mineral oil and is the only oil proven to reduce protein loss. Protein loss in hair leads to dryness and breakage. The lauric acid in coconut oil has a low molecular weight, which helps penetrate and nourish the hair with vitamins, minerals and the medium-chain fatty acids. These oils have been tested in the lab of human hair according to the International Journal of Cosmetic Science.
The important part for hair penetration is the medium-length triglycerides. A key to whether or not an oil penetrates into the hair is the amount of triglyceride and short-chain fatty acid it contains, as well as how the components of the triglyceride are arranged. Lipid molecules need to be small to penetrate into hair (less than 18-20 carbon atoms), but that's NOT the only variable because oils are not composed merely of one kind of lipid, they’re composed of many different lipid ingredients.
According to Wendy the Hair Scientist, “Usually oils are non-polar and this is a big difference in chemistry to have an electrostatic (+ and -) interaction versus just having some oil form a FILM over your hair. This helps those triglycerides be actively pulled through the cuticle-membrane complex over your hair shafts to the INNER portions. In addition to the above and as a rule of thumb, monounsaturated fats tend to be better at penetrating your hair than polyunsaturated fats”.
“What that really means is that these small, compact (non-branching) molecules penetrate the hair more deeply whereas larger lipids may only reside in the cuticle layers of your hair or on top because they are less compact and more branching”.
If your hair needs a great deal of softening and protection from swelling in water like my porous hair, the deeper-penetrating oils are a better choice. The reason to use penetrating oils is not really to “waterproof” hair, but to manage porosity in porous hair. Oils only slow water loss, they don't actively preserve water.
Note: Penetrating oils take hours to soak in.
There are a few things that determine whether an oil can "soak in" to your hair. One of them is fat saturation because that dictates the shape of the molecules. Another issue is carbon chain length of the fatty acid. The shorter chains can soak in, but larger-chain fatty acids are too large to do that. As mentioned above, a third issue is the presence of triglycerides that are small enough molecules to soak in to hair (ex. medium chain triglycerides in coconut oil).
Why are non-penetrating oils used in products? They help hair shine, decrease friction, and fewer tangles. Not EVERYBODY needs oils to soak into their hair.
Just because a coating oil like jojoba oil does not penetrate beneath the cuticle doesn't mean it isn't BENEFICIAL. Jojoba oil is a wax ester (no triglycerides or oleic acid). Most oils are primarily fatty acids, wax esters are a combination of fatty acid plus fatty alcohol. Human sebum is somewhere around 15%-25% wax esters. So jojoba is about 15%-25% which mimics sebum. It can be a great lubricant which protects cuticles from breakage by reducing friction, not to mention the cosmetic benefits of properly lubricated hair.
For those using oils who don’t need to, perhaps your hair is dry or brittle, because you are not consuming enough fresh water, which is by the way the best way to keep your hair hydrated.
To view oils that penetrate, visit Wendy’s blog below (highlighted).
Sources: Wendy, Hair Scientist. Investigation of Penetration Abilities of Various Oils into Human Hair Fibers. Journal of Cosmetic Science.