Friday, September 14, 2012

Oils and how they moisturize/penetrate the hair.

Most of the following information is from here: Do oils moisturize?

Only water adds moisture to the hair, BUT oils can seal water in the hair strand. Sealing oils should be used only on wet hair, so that they don't seal water out of the hair, but into the hair. I will point out the sealing (non-penetrating) oils in this entry with the color green.

Oils (that penetrate the hair shaft) can also replace lost essential fatty acids which are part of the molecular structure of the hair (these EFA need replacing more and more as the hair is longer) and give the hair more plasticity as well as make it feel softer. These oils can be used on dry hair, wet hair contains water inside the shaft and may keep out some of the oil. Sealing oils can keep out penetrating oils. I will point out penetrating oils in this entry with the color red.

"Oil is able to penetrate the hair shaft only if it has more affinity for the hair proteins. This affinity is consequent upon the structure of the oil. Triglycerides of principal fatty acids (like lauric acid, myristic acid, palmitic acid and stearic acid) have a relatively simple straight chain structure and low molecular weight. Therefore, these oils are able to penetrate the hair shaft better. One example of such oil is Coconut oil. On the other hand, oils, which have relatively heavy structures and have no affinity for the hair proteins are not able to penetrate the hair shaft very well. These include mineral oils like sunflower oil. Jojoba oil doesn’t penetrate hair (only the skin); it is great as sealing oil though.

Scientists now agree that straight chain glycerides like olive oil without difficulty penetrate into the hair. Polyunsaturated oils, like Jojoba oil, are more open in their structure so they don’t pass through the layers of cuticle very well. Therefore, oils like Olive oil and Avocado Oil penetrate the hair shaft more readily and better. Meadow foam seed oil partially penetrates, and jojoba and sunflower oils don’t penetrate at all. Most other oils, including safflower oil, do not penetrate hair very well because of their open structures." (source)

"Oils are moisturizers. There are 4 types of moisturizers: Occlusives, Humectants, Emollients, and Proteins. Read more here.
Occlusives physically block water loss, and include petrolatum, lanolin, mineral oil, silicones, and some non-penetrating oils.
Humectants attract water to the hair and include glycerin, propylene glycol, sorbitol, honey, syrup, aloe vera gel.
Emollients smooth the surface by filling spaces with droplets of oil and include most plant oils and butters. Some penetrate the hair shaft more than others. I made a list here of the constituent fatty acids of different oils.
Proteins replenish protein and include collagen, keratin, elastin, and protein." (source)

"Straight chain glycerides are oils that penetrate:
Castor Oil
Palm Kernel
Sweet Almond

 Oils that partially penetrate:
Meadowfoam seed

 Polyunsaturated oils sit on top of hair:
Broccoli Seed
Mineral oil

Oils with high penetration
Coconut oil
Ucuuba butter
Sunflower oil
Palm kernel oil (i.e. Red Palm Oil
Babbasu oil

Oils with some penetration, in decreasing order (based on lipid composition)
Castor oil
Olive oil
Avocado oil
Corn oil
Canola oil
Mustard seed oil
Sweet almond oil
Apricot kernel oil
Argan oil
Sesame seed oil
Shea butter
Peanut oil
Kokum butter
Grapeseed oil
Rose hip oil
Hemp seed oil
Flax seed (linseed) oil
Perilla oil
Safflower oil
Cocoa butter

Oils with little to no hair penetration
Rice bran oil
Mineral oil
Jojoba oil

Other interesting reads: Humectants (Moisturizing Agents) Effect of mineral oil, sunflower oil, and coconut oil on prevention of hair damage and Mineral Oil: The surprising moisturizer, especially in conditions of low humidity and it is antistaticSecondary ion mass spectrometric investigation of penetration of coconut and mineral oils into human hair fibers: relevance to hair damage. Effect of oil films on moisture vapor absorption on human hair. Investigation of penetration abilities of various oils into human hair fibers. pre wash oiling v/s after wash oiling


  1. Thanks for this list! I was trying to figure out which category coconut and grapeseed oils fall into. I just started using the grapeseed and my hair responds completely differently to it than coconut. This is a good explanation of why!

    1. No problem! I'm glad you found it useful! :)

    2. this is very useful! thanks a bunch:-)

  2. Wow. This right here is amazing. Thank you for putting in the effort and sharing this information with us

  3. Thank you for this! I recently stated conditioning with jojoba, and my hair wasn't reacting the same way as it did olive oil.

    Does honey penetrate the hair at all? What exactly does honey do, I see people use it as a hair mask does it work?

    1. I'm really glad you found it useful. Thank you for the lovely comment! :)
      Honey is a humectant, it draws moisture from the air into the hair, or if the air is dry it draws moisture from your hair. I talk about humectants here:

  4. Thanks for the info.

  5. hi adelina my name is tine..i need a list of a few everyday conditioners that has NO protein in them can you name some for me..i know honsuckle rose is one but i dont really like that one its too heavy an a little waxy feeling on my hair so do you know of any others? thanks :)

    1. Yes to Carrots is one of my favorite conditioners without protein. Others that I like have been discontinued or changed their recipe to add protein, so that's the only one I've tried and is still around.

  6. what happens if I mix penetrating and non penetrating oils together and use them on my hair? will the penetrating oils still be able to get in or will the other oils block them out?

    1. I don't know for sure, but if I had to guess I'd say yes. It's better to just stick with one type at a time.

  7. Hi there! I have a question... If I prefer to use an oil as a moisturizer ( coconut oil and avocado oil) should this be done on dry hair instead of wet hair? I know these oils penetrate the hair but are they strong enough to penetrate wet hair?

    1. As the entry above says: penetrative oils should be used on dry hair. Water and oil repel each other and water will keep oil out of the strand.

  8. If my is thinning on top (I am female) due hereditary reasons would castor oil help enciyragecnew hair growth?

    1. There is not much we can do about genes, but it's worth a try. You may want to read this entry for more info on growing thicker hair:

  9. I know i am super late but thank you for this post. I could not find anyone who actually listed the old and their differences

    1. You're welcome! I'm glad you found it informative.

  10. Thank you very much for sharing, Adelina. May I ask you, which oil is less likely to fade my hair color if I use a couple drops on my wet, clean hair? Is jojoba oil better than avocado/olive oil for this purpose? Thank you much

    1. I'm sorry I have no idea which oils can fade hair color because I never used oil when I used chemical hair color, I only used it with henna and henna never fades. My advice is to test it out, your hair might not react the same as someone else's hair to the same exact oil. Good luck and I hope you find something that works for you!


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