Hair Care Penetrating Or Sealing Oils

Know Which One To Use Penetrating Or Sealing Oils

Posted on Posted in Hair Care, Hair Transition, Healthy Hair

Judging by the number of times I talked about vegetable oils and recommended its use over the use of mineral oil, you know that they have an important role in achieving and maintaining healthy hair. However, not all oils are the same they will either be penetrating or sealing oils. Do you know which oils are which and why? Find out why you can accomplish better results when you know which oils to use.



What Are They & Why Are They Good

Vegetable oils are extracted from the seeds of plants to produce a viscous, lubricating liquid mainly composed of triglycerides. The list is extensive and there are many different oils such as coconut oil, olive oil, sesame oil, almond oil, macadamia oil, cocoa butter, shea butter or argan oil.


The use of vegetable oils in your hair is beneficial not only for the outer structure of the hair, the cuticle layers but also for its inner structure, the cortex (read this post to know more about hair structure).  The cuticle layers of the hair can be easily damaged by manipulation, styling tools, chemical treatments or environmental factors. Applying oils to the hair will seal the hair and help to prevent and protect it from these damaging effects.

Cross section of hair strand

Other positive effects include added shine,  hair lubrication which facilitates the detangling process and lessens a number of tangles in your hair, a decreased number of split ends and less hair friction. If, however, you are not excited as I am by these attractive features, then I believe you will quickly change your mind.


Having beautiful hair on the outside is nice, but if this beauty is not a reflection of inner health then it will be short lived. Healthy hair demands a healthy cortex! This is the largest/thickest component of the hair and it’s also the cortex that provides the hair with its strength and elasticity. When oil is applied to the hair it is essentially reinforcing these characteristics. Oils will give your curly hair its bounce, they increase its tensile properties. In other words, your hair when stretched will be able to sustain tension and go back to its original shape without breaking or losing form. However, not all oils are the same.



Not All Oils Are Alike

Different oils have different molecular structures. For us to know which oils are penetrating or sealing the hair, we need to know the triglyceride and fatty acid content of an oil. The is where the information can become a little, to say the least, scientific, technical and wordy and because I am not training you to be little Einsteins I’ll try to make this as simple as possible.

Spoon pouring oil

The molecular structure of vegetable oils is composed of glycerol (triglycerides) which has three carbon atoms, and fatty acids which have long chains of carbon atoms. The shorter the fatty acid chain of an oil is (less than 20 carbon atom chains), the bigger its penetrating ability is.


Moreover, according to a study about the penetrating abilities of oils in human hair,  it seems that some oils with short carbon chains have a positive charge interacting with the proteins inside the cortex. Meaning that these oils will penetrate the hair to bond with those proteins.  The study also states that monounsaturated oils penetrate into the hair shaft better than polyunsaturated oils because of their compact molecular structure and slight positive charge.



Penetrating Oils or Sealing Oils?

Now you know why some oils penetrate the hair shaft and others just stay on top. If you’re thinking “I could probably do without the chemistry lesson”, let me tell you this was the short version of a very lengthy lesson. As an example, coconut oil or olive oil are oils that penetrate the hair. Castor Oil or sweet almond oil are sealing oils and create a film around the hair strand.


Here’s a PDF list of +25 penetrating and sealing oils you can download and keep for future reference. Enjoy it!

Penetrating and Sealing Oils (1)

Moving on, according to findings from this study, oils that can penetrate the hair shaft also leave a thin protective film over the cuticle layers. This means they also seal your hair, but they thin down throughout the day and disappear/soak in. You should also know that oils like coconut oil, olive oil, sunflower oil or avocado oil sink into the hair easier when heat is applied. So if you want to achieve better results when using them grab your hooded dryer, hair dryer or heat them in your microwave and know that you’re doing the best for your hair.


Whether you choose a penetrating or sealing oil, it depends on your hair and what you want to achieve. In essence, all oils help to condition hair, they are good moisturisers even though they don’t have any water in them. In fact, they are hydrophobic, meaning that they repel, they don’t mix with water. What they are good in is in reducing water evaporation from inside the hair or in dry climates either by penetrating or sealing your hair. This is good because natural hair is thirsty for water, we need all we can get.



When To Use Your Oils

Pre-Poo – I’ve talked about pre-pooing and even said it is a practice (oil pre-poo)  in my hair regimen that prevented my weak relaxed hair from breaking heavily at the line of demarcation. This will protect your hair from shampoos that strip the natural oils from your hair. I believe this is the best time to use penetrating oils because they will protect the cortex of the hair. Coconut oil is proven to reduce protein loss and protect from hygral fatigue, but you can choose another oil.


Oil rinse – Again, for greater results, use penetrating oils such as coconut oil, avocado oil, extra virgin olive oil orAvocado Oil any other penetrating oil. Do this while you wash your hair it will add moisture retention, facilitate detangling, reduce frizz and single strand knots.


Deep Condition – Do your own oil mix for you homemade recipes or for your store bought deep conditioners. Because you are trying to nourish your hair use oils that have the ability to penetrate through the cuticle layers and into the cortex.


Seal Hair – Use sealing oils to lock in the moisture after you have washed and moisturised your hair, when you want to protect the ends of your hair, or when you want some shine. You can also use it to avoid tangles or hair friction that can damage hair cuticles and cause split ends and holes in the hair shaft. Read this post to know more about sealing your hair.


Frizz Control – Use a sealing oil if you which to control your frizz or flyaway hair.  You can also use an oil that penetrates and seal at the same time such as grapeseed oil or argan oil. However, these leave a lighter protective film than a sealing oil.


There are many situations in which you will want to use oils and if you don’t know which ones to use ask yourself this:


“Do you want to protect and strengthen the cortex of your hair from washing, styling tools, chemical treatments and the environment? Or, do you just want to seal in the moisture inside and avoid rapid evaporation?”


If you said yes to the first you will want to use penetrating oils, and if you said yes to the second use sealing oils. However, if you don’t know or maybe it’s a mixture a both, use penetrating and sealing oils, either in an oil mix or by doing a pre-poo/oil rinse and then locking in the moisture.

Note: If you have fine hair you may not like a heavy oil like castor or olive oil because they tend to weigh down your hair or/and make it greasy. On the other hand, coarser hair, high porosity hair, chemically treated or damaged hair may love them.


I hope you found this post useful. Don’t forget to download your Free PDF List.

Penetrating and Sealing Oils (1)

What oils do you use & what do you sue the for?

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24 thoughts on “Know Which One To Use Penetrating Or Sealing Oils

  1. Very informative, maybe a couple more bullet points to make it seem less like a paper! But all in all it looks a flows great!

  2. Hello Monica,

    Again, another great article.
    I knew you could use most oils on your hair but I did not know which kind worked best for each hair type. My preferred method is Olive Oil but I am going to try Coconut Oil as well. I have dry,treated and frizzy hair.
    Thanks so much for sharing.

    1. Hello Mary,
      I’m glad the info was helpful. Olive oil is good, but coconut oil is a better choice specially if you had chemical treatments on your hair. It will penetrate your hair, keep it hydrated and strengthen it.

  3. It is great to know the difference between Vegetable oil and Mineral oil. I much prefer vegetable oil as it has more benefit and you mention it right.
    Sometime, we have to pay close attention to our hair treatment carefully.
    Thanks for sharing your insight here. It is very informative!


  4. I was looking for something which I can use to control Frizz. Now I know grapeseed oil or argan oil is the answer. Thanks for sharing this article.

  5. Urghhh!! I have this problem everyday!! I struggle day in and day out with my curly hair, and what sort of serums and oils I should put into it!

    Thanks for the share!


    1. Hello Brooke, thanks! I hope this article has brought you some clarity as to what sort of oils you need to get the results you want.

      1. Monica, I’m having the hardest time trying to download the PDF list of sealing and penetrating oils that you have on your site. Can you please help me with this? I have no idea how to get to it.

        1. Hi Jamie,

          To access the PDF list you have to sign up for it. Once you do this you will get access to the free PDF and others. Have you signed up? Check your emails (don’t forget to check the spam folder).

  6. So do I still have to use to different types of oils? A sealant and a penetrating? Because my haor is really drunk I need to.oil it everday

    1. Hi, Cheryl!

      You should use penetrating or sealing oils depending on what you want to accomplish and your hair needs. As for using different types of oils, no, you don’t need to use different types. Assess you hair needs. Does your hair dry quickly after you moisturise and apply your oil? If you’re using a penetrating oil you may need to change it and use a thicker oil, one whose protective film around the hair strand is thicker like olive oil. Or maybe you just need a sealing oil like grapeseed oil to help keep the moisture in for longer. During my transition, I alternated my LOC method with olive or grapeseed oil. Now, I like using coconut oil (penetrating) because it strengthens my hair and is lighter. Alternatively, you can also make your own oil mix with penetrating and sealing oils and see how it goes.

      What do mean when you say “drunk”? Do you mean dry? If your hair is dry and you feel you need to oil it every day then I need to ask you if you moisturise your hair before you apply your oil? If you’re not doing this then you are promoting more dryness. The oil will prevent/block any moisture from getting in your hair. Just as oils block moisture from getting out of your hair and help keep dryness away, they can also block it from getting in and make your hair dry. Moreover, know that even if you use your oils correctly to keep the moisture in, the moisture will eventually evaporate and you will need to supply your hair with more.

      Also, check to see if you have high or low porosity hair. High porosity hair can drink and get drunk on moisture and still feel dry while low porosity hair can have a hard time getting moisture in. In this case, read this article to know more about it and this one to know how to address hair porosity.

      I hope this answers your question, if not, reply to this message here or on facebook. Maybe we can go over your regimen and see what could be wrong. Oh, also check this post, it will help you build a hair regimen.

      All the best,

  7. It will depend. Personnaly i hate using penetrating oil for oil rinse. they don’t give me the needed. I really like castor oil for my oil rinse. I love using penetrating oils for prepoo, leave in, deep treatment or as a serum.

    1. Yes, Nadege, you can use whatever oil (penetrating or sealing) oil you like. It’s great you discovered you get more out of sealing oils. I personally feel heavy oils like castor oil will block will block whatever comes next, like your moisturiser, even though much of it is rinsed off. But this is probably the effects of my low porosity hair. Still, I prefer doing oil pre-poos.


  8. is castor oil penetrating or sealing .I colour my hair red and wondered if caster oil would be a good hair treatment without stripping the colour which coconut oil does

  9. Hi Monica, I’m a new natural and I need help. I wear a TWA and like to wash n go. My current regimen is wetting my hair, applying coconut oil, then applying Shea Moisture Coconut & Hibiscus Curl & Style Milk. It looks beautiful wet but once it dries, it’s like hay. I’m now thinking that maybe coconut oil isn’t for me. What do you recommend?

    1. Hi Shaunte,

      Your dryness can be due to a lot of things. Have you tried using the Shea Moisture Milk before the oil? I believe it would be better for your hair. Although coconut oil is a penetrating oil and wouldn’t completely block your hair from taking in the hair milk it would still create some kind of barrier. Secondly, water is a moisturiser but it easily evaporates, thus why we have products with oils, humectants and emulsifiers – to blend these ingredients together and retain moisture inside the hair for longer. Therefore, if you use a penetrating oil (that seals, but not much) you are still losing moisture and the milk applied in the end is not getting in completely, so moisture is not enough for your hair.

      My advice would be for you to use the hair milk and then a sealing oil like almond oil, jojoba, grapeseed or castor oil. Also, check your hair texture, if you have medium to coarse hair Shea moisture’s hair milk may be too light for your hair. If so, try a hair butter or a heavier moisturiser and then use the oil to seal your hair.

      One last thing, do you clarify your hair? Check this post and this one.

      Hope this helps Shaunte, without knowing more about your hair routine I can only give you these tips. Let me know how they worked for you.

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