Part 1 of 2: Porosity - Definition and Causes

What is porosity? Scientifically this would mean creating pores in the hair structure. However, this definition would encompass breaks or cracks as well in terms of measuring if hair takes up more water due to the porosity. Instead of trying to describe it in words, I will use diagrams. (If you need an introduction to the structure of hair – click here). The three figures below all illustrate how hair can develop porosity

Porosity IS a form of damage to the hair. It can be caused by many reasons and just because you are natural, it doesn’t mean you can escape it!! Here are a few causes of porosity

1. Shampooing, Towel Drying and Combing
These three are some of the most common reasons for cuticle damage. They can cause any of the damage seen in the figures above and it is mostly attributed to one main factor, mechanical damage (Journal of the Society of Cosmetic Chemists, pg 155-161, 1976.). Mechanical damage happens when scrubbing the hair with shampoo, rubbing the wet hair with a towel and combing hair to remove tangles. The more aggressive you are at any of these activities, the more susceptible your hair will be to damage.

2. Long Hair
The longer your hair has been on your head, the more likely it is to have a damaged cuticle simply because it will have been exposed to number 1 multiple times (Journal of the Society of Cosmetic Chemists, pg 155-75, 1975.).

3. Light
UV light/sunlight has also been seen to damage the cuticle with one study showing that damage starts after 200 hours of exposure which is a fairly long time.
(Journal of Cosmetic Science, 303-315, 2008).

4. Chemical Treatment (Relaxing and Bleaching)

Both these processes are an open invitation to porosity (bigger and better than ever). Cuticle lifting, cracks, holes are common with the added punch of entire sections of cuticle missing
(Journal of the Society of Cosmetic Chemists, pg 347-371, 1993).

5. Others
– Environmental conditions such as dirt,wind, humidity as well as thermal treatment (heat setting, blow drying, flat ironing).
Now this pretty much means that anything can cause hair to become porous. I will be detailing in the next segment how some of this porosity can be dealt with. For now I will emphasize two things.

1. Everyone’s hair is different. Two people can have the same hair colour applied to their tresses and one will have their fall off (me :) ) while another will not (for example Jenteel).

2. The hair cuticle actually consists of about 5-7 layers, therefore if one layer is damaged, it can break off et voila, you have a strand that looks like new (Journal of the Society of Cosmetic Chemists, pg 155-75, 1978.). This is shown in the diagram below.
Tune in next week for Part 2 of 2 - How to tackle porosity - this will cover the reasons why porosity is a concern and also the cold water and apple cider vinegar theories of 'fixing' porous hair.........(cue mysterious music :))


  1. You're fantastic! Great post ;)

  2. Thanks for these informations! I can't wait for the part 2. Your blog is so interesting... Thank you so much for sharing all your knowledge with us!

  3. Love the way you easily explain everything! Thanks!

  4. I still don't get it. I can see an "actual" hole on one individual strand toward the end of the strand. I'm looking at it right now. Is this porosity? or normal breakage?

  5. very interesting. i love it.

  6. luv ur blog!!


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