Monday, September 16, 2013

Different Porosity, Same Hair

It's fairly common to have hair that is porous on the ends, but not at the roots. That means different parts or your hair require rather different care. How easily your hair becomes porous with just normal wear and tear and weathering depends on a lot of things. In fact, the kind of porosity your hair accumulates can be very different from person to person.

How can the ends of your hair become porous? The ends of your hair are the oldest - they have had the most time to accumulate damage. While you up to 11 layers of cuticles covering your hair, if your hair is long there may be few layers left on the ends.  Brushing, combing, detangling, sleeping, wearing hats and collars, blowing around in the wind, wearing ponytails and braids and barrettes; these activities cause cuticles to chip or break away completely. Even more dramatic is over-washing the hair (especially if using strong or concentrated detergents), bleaching, highlighting or lightening the hair, permanent dyeing the hair (when they dye includes ammonia and/or peroxide), chemically relaxing or permanent waving the hair. Spending lots of time in the sun causes cuticles to shrink so they cover less area. Using high heat hair styling tools can cause cracks that increase porosity.

Hair that curls or has kinking (or both) "wears" or weathers more unevenly than straight hair because there are certain areas which accumulate more friction than others, so it is more likely to become porous. Anything that sticks out can be broken off easily - and that goes for cuticles on your hair where it kinks and curls.

Fine and medium hair is more flexible than coarse hair and tends to become porous more easily because it bends around things (like other hairs) readily and therefore accumulates more surface-contact with objects and that means more friction!

What's the problem with porous hair?
Porous hair loses water more quickly than low porosity hair. Think of the function of the cuticle of low porosity hair as a plastic bag. Not very porous. Water doesn't get in or out easily. But if you punch holes in a plastic bag or rip tiny cracks, water can get through. When your hair is porous, water gets in and out easily. So when you put your hair in water, it takes on water and swells. Swelling is bad for hair because it creates stress within the hair. When porous hair gets wet, it can lose soluble proteins to the water. Bad news - because those proteins in the outer portions of your hair help keep it hydrated. When porous hair is dry (dry meaning not wet), because it has no tight barrier against the environment, so it can lose more moisture than is good for it when the air around the hair is drier than the hair itself.

Hair may grow out of your scalp with low porosity. It may not stay that way for long, depending on what you do to it and what your hair is like.  For whatever reason hair becomes porous, porous hair becomes dehydrated easily and dehydrated hair is more brittle and prone to breakage, less shiny, does not hold a curl as well, frizzes easily.

What to do
Low porosity hair is water-repelling. Not as much as  the back of a duck - but it does not swell with water quickly when wetted and it does not lose water very readily to the environment around it when dry. Because normal-porosity hair is so resilient to the environment, and because it tends to stay resilient, it's a good idea to encourage more-porous hair to act like less-porous hair. Water-repellant hair does not swell in water, accumulating more stress and more damage. It resists damage. It does not become dehydrated quickly! It does not absorb humidity rapidly and frizz immediately. We want our hair to repel water somewhat.

If your hair is porous on the lower portion, what can you do to balance out your hair's porosity?
  • Pre-shampoo (pre-cleansing) oil treatments on the porous areas - ends and probably the top layer too. Especially with oils like coconut, sunflower, grapeseed, avocado or olive oil. Enough oil to add shine - or enough to make your hair look greasy - that's up to you. Oils will repel water during cleansing to prevent the swelling that can cause further damage. You'll know you used the right amount when your hair, post-washing does not look frizzed out and extra-poofy, nor greasy and lank when dry. If just your ends are porous - use this treatment only in those places.
  • Condition-wash-condition. Pre-shampoo conditioning also buffers hair from shampoo and water, but conditioners can build up in a way that liquid oils do not. If the idea of using oils in your hair make you say "yuck," this method can give you wonderful results. The conditioner before washing can be applied to wet or dry hair. 
  • Use shampoo, conditioner or styling products which contain proteins or amino acids or film-forming humectants. This link has a list of products based on film forming humectants. Proteins and amino acids are hydrating to hair and can help hair that tends to be dehydrated, hold on to moisture. Film forming humectants (flaxseed gel, okra gel, aloe vera gel, pectin, celluloses) are not especially affected by ambient humidity and can seal in moisture all day to keep porous hair hydrated. 

How can you prevent your hair from becoming porous?
  • Comb, don't brush. Or skip the comb entirely and just use your fingers. Brushes are great for shredding cuticles of your hair! A wide-tooth comb will get the job done. If you have tangly hair, detangle starting with your fingers, then a wide-tooth comb and work from the ends, up. Don't tug or yank on hair! Once you over-stretch a hair, it's damaged forever.
  • Use ammonia-free and peroxide-free or low-peroxide, semi-permanent hair dye or plant dyes like henna.
  • Shampoo only when your hair needs it. Switch to "sulfate free" shampoo or dilute your shampoo to make it more gentle to the hair.
  • Use lower-heat hair styling tools.
  • If fabric touches your hair and your hair becomes porous easily - make sure it's silk or satin or at least slippery-feeling fabric.
  • If you use henna in your hair - make sure it has plenty of lubrication because henna increases friction in hair.



9 comments:

  1. What is your opinion on the anti-air drying study going around? (If you are not familiar basically they "proved" that leaving your hair wet for a longer period of time is more damaging than blow drying from a distance without manipulation due to damage from the swelling of the hair shaft over a longer period of time.) Personally I think it's wrong based on my own experience.. plus blow drying my hair from a distance without manipulation would be the best way I could think of to make myself look like an escapee from an asylum, lol.. but you have more scientific knowledge than I on the subject so I was curious what you thought.

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    1. Waymire01,

      I have seen that study. In the air-dried hair, the cell membrane complex was damaged but not in the other (different temperature blow-drying) groups. Before digging in, it's important to note that it is not well known whether this "damage" to the cell membrane cortex is really a structural problem for hair health and strength. Human hair is built to be air dried, after all. Nature gave us hair to protect our heads and we've managed all these generations despite not having hair dryers, so it is really that big a problem? Probably not!

      Blow-drying causes surface damage that increases with temperature because the cuticles of the hair change in moisture and temperature quickly. This causes cracks in the cuticle. Air drying does not have as great an effect on the hair surface.

      But when normal porosity and porous hair is wetted, it absorbs water. As it absorbs water, it swells - but the inner portion which includes the cell membrane complex does the swelling. Cuticles cannot swell or increase in girth. So we have a problem - a swelling interior and a non-swelling exterior! That's stress - like frozen water inside a pipe.

      So, yes it is true - if your hair stays wet for hours it accumulates a lot of *internal stress* and that is not very good for it. But air-drying causes less *external* damage which appears in overly blow-dried hair as dullness and roughness.

      There are a lot of compromises, though. I'll make a list.

      1) Use hair-penetrating oil treatments for 6-12 hours, especially on the length of your hair. Coconut oil or sunflower oil, or olive or castor oil. These will help porous hair *behave* as though it is less-porous. It will swell less in water and you can avoid this problem! This really works. You don't have to soak your hair with oil either. See this post for details: http://science-yhairblog.blogspot.com/2014/03/oil-pre-shampoo-or-pre-wash.html
      You may even find you have a faster drying time with these treatments.
      2) Squeeze water out of your hair (styled or not) before air-drying. It will dry more quickly.
      3) Limit your time under the water. I.e. wash your hair last. The less time it spends under water, the less saturated (I mean - waterlogged) it will be.
      4) Wash less often. Works for some, not others.
      5) Go as light on the styling products as possible. Lots of leave-in conditioner and lots of hair gel causes longer drying times.

      For those who need a lot of hair gel because you have a lot of hair, need a lot of help with definition or use flaxseed gel - in which case "too much gel" is really "just right" - a few minutes of blow-drying with a diffuser can take half an hour or more off drying time. But as noted at the start, I don't think it's worth worrying about something that isn't clearly a problem. Certainly when I spend all day out in the rain with wet hair, my hair acts strangely and takes a week of trying this and that to get back to normal. Waterlogged hair is troublesome hair. But the things we do to make our hair look good and be healthy like oil deep treatments also protect it during wetting and washing.

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  2. Thanks!
    My hair seems to be particularly sensitive to blow drying in any form. I've tried low heat, no heat, diffusers, air brushes.. they all dehydrate my hair. Ceasing blow drying was one of the biggest benefits I've done for my hair. Even occasional flat iron use doesn't hurt it like blow drying does.

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  3. So what about African American hair virgin (not altering) kinky hair that is very low porosity, the hair shaft seems to only open with heat. I do not tend to use heat except warm water to wash. My hair is typically able to hydrate but it seems this winter season I'm having to learn it all over again.

    Facts:
    Very low porosity

    Protein sensitive

    Fine strands - thick dense hair (many strands)

    Can use hydrolyzed soy protein (khoret amen hair smoothie)

    Can not use Giovanni direct leave but it has soy, (it's very watery though)- confused

    Can not use wheat proteins (crunchy and moisture sits on hair)

    From reading your articles my hair does not like the high molecular sized proteins (oat protein I won't be trying-thsnn you)

    Need heavier sealants

    Hair likes olive oil

    Hair dislikes coconut oil

    Questions:
    What would help to open hair shaft, and science wise what are your findings from those of us who deal with this?

    How do you recommend reclaiming hair shaft, I used to use cold aloe Vera water. (myth of helpful?)

    Any links or patterns in my hair traits?

    Thanks for any effort.

    Fyi-very interesting posts, you should go YouTube videos. My moms a bio chemist I'll be send these to her, I think she'd enjoy the findings.

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    1. Hello Michi,
      Interesting questions! First of all, the Khoret Amen Hair Smoothie and Giovanni Direct Leave-in are very, very different products. Khoret smoothie has very substantive/cationic (bonds to hair) conditioning ingredients, is rich in oils and other emollients. Lots of times, hair can tolerate proteins if they are "balanced" with emollients. Protein gives hair support and a more-dense feeling. Emollients soften and add flexibility. Your hair needs the support of protein well-balanced with the softness of emollients to avoid an unpleasant outcome. Giovanni Direct Leave-In is thinner, has no substantive/cationic conditioning ingredients, very different indeed. So from that, you can confirm that your hair does like lots of emollients as long as they're contained in a well-emulsified product.

      From what you describe - your hair does the "low porosity thing" to the letter! Dislikes coconut oil, can't take too much protein, gets crunchy with some ingredients.

      You err in favor of emollients to soften, add flexibility and lubrication and occasional protein for support any hydration (hydrolyzed proteins do hold on to water well for hydration). To me, it sounds like you already have your hair figured out - what it prefers, what to avoid.

      For opening the hair shaft, the gentle way is to use mild, moist heat - just a little bit higher than body temperature - comfortable shower-water temperature. The heat causes slight swelling - enough to allow more surface area for conditioners to bond with and more access beneath the cuticles for oils, proteins and conditioners. Hair recovers from this quite easily.

      Other things that open the hair shaft tend to be more aggressive like full-strength shampoos, repeated baking soda treatments, soap bar lather. For low porosity hair, the impact of these more-aggressive treatments is less than for porous hair. Shampoos, especially those formulated for oily or "normal" hair often cause hair swelling - that results in a lifted cuticle. Alkaline products like baking soda and soap bars have the potential to strip off the layer of bonded-on lipids that exist on top of the cuticle. This layer is hydrophobic - water repelling. It also repels conditioner and oils. With repeated use, if that layer is eroded, hair becomes more hydrophilic, attracting water and conditioner. For some people, this is a desirable result. But it also makes hair more fragile and in need of more careful care to prevent dehydration and brittleness. Alkaline products also cause swelling of the hair shaft, which makes it temporarily more porous.

      To restore the cuticle to its normal position, restoring normal temperature, getting the hair dry, and rinsing in water with a pH near neutral (not all tap water is in this range!) are all that is needed. For some people, cuticles actually pop up as hair swells in acidic solutions. Low porosity hair is less likely to have this reaction in acidic rinses. Human hair is at it's most resilient between pH of 4.5-6. Outside that range, hair is more likely to swell, lose interior, soluble proteins and be vulnerable to damage.

      I hope that helps - the post about low porosity hair and managing elasticity and porosity in hair might have some helpful information or visual aids. Good luck!

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    2. Although I am not African American my hair is very fine, hates protein, and has a lot of difficulty absorbing some products.. and is prone to build up even with natural, water soluble ingredients. I just wanted to give a suggestion.. I do a lot better with fatty alcohols, and humectants for moisture. Unfortunately these can be hard to find in specialty and natural brands. My current HG is Tresseme Naturals conditioner (the avocado version), I've been cowashing and conditioner styling with it for a couple of months now and am very happy with my hair. It's literally the only product other than water that has touched it. I do cowash daily if I'm wearing my hair loose but can go a day or two without if I'm willing to do a updo or other style.. and my hair has stayed nice and moisturized.

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  4. So I am in need of SERIOUS HELP! I'm about ready to give up on this hair of mine to be honest. My hair is so odd and I'm not entirely sure why but I do have an unconfirmed theory. The hair on my head is not the same at all. The very nape of my neck has silky 3c curls but as you go up the hair becomes more coarse. The curls are different though ranging in diameter (tiny corkscrew to bigger ones) At the center of the back of my head is an area that is IMPOSSIBLY DRY. I have no idea what is going on with that one section but it feels wiry and coarse no matter what I do! Going towards the top of my head my hair feels silkier and it becomes wavy/ curly and the strands thick. The sides of my hair are much finer nowhere near as thick (or soft) as the top of my head and the curls are smaller (4aish). The hair by my ears, however, are incredibly silky strands! Clumpy thick and ZERO frizz (3b). It makes absolutely no sense how this can be on the same head. At the very very front of my head where my forehead meets my hair it's 4b (small curls fine strands thin thin) And scattered throughout my whole head are straight silky hair strands ranging in diameter! Basically my hair is a tangled disaster and a complete mystery to me. Most of the time I'm scared to comb my hair and I don't because of these conflicting strand textures / strand types / diameters and porosity. I honestly feel as if I have the strangest hair and I've yet to encounter anybody on the internet who has my issue. I know without a doubt that I have both low and high porosity strands in different sections of my hair and I don't know what to do. I don't understand my hair at all. As far as my theory goes I believe I suffer from hypothyroid but I'm looking to get tested officially. I have metal fillings in my mouth and I also believe I suffer from mercury toxicity which I THINK could also be doing a thing or two to my hair. HONESTLY it's hard to say but I don't remeber my hair being as fine and thin in different areas as it is right now. Any and I mean ANY input you have on Any of the issues I brought up in this would be wonderful!! You seem to have fantastic knowledge when it comes to hair so any correlation you can think of or any solutions you can come up with would be WONDERFUL! Thank you!

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    1. You are not alone! Lots of people have really different curl patterns on their heads. Or different widths. I have hairs on the back of my head that are 140 microns and at the front that are 45 microns wide and that's not terribly unusual. We're human - there's gotta be some variation, right? Just to keep things interesting.
      So you have- Nape: silky, 3c curls
      -Center-back: More coarse, smaller curl, feels very dry
      -Crown: Silky, wavy/curly, feels finer
      -Sides: Finer, small curls (4a)
      -Around ears: finest hair, 3b, not frizzy
      -Front hairline: fine, 4b curls
      First of all, in the right hands, you could have all sorts of cool haircuts with all these different curl patterns. Your biggest "different hair" place is the center-back which is more coarse. I hear from people who have a coarser section of hair frequently that it feels dry. That is often because the more-coarse hair is also less flexible and less soft, which is a drier feeling than silkier hair. For some people, that more-coarse section will also be more porous because it's not getting the special care it needs, or because of hard water, but more often it isn't more porous, it's just more coarse.

      So a good place to start is by treating that section of your hair differently. Every time you wash, put a hair-penetrating oil like coconut or sunflower oil or avocado oil on that section and leave it on for 6-8 hours so it has time to soak in and soften strands. Do the same for your more tightly-curled areas like the front hairline. If you're consistent with this, you might notice some changes, especially in the more-coarse hair in terms of flexibility. Coarse hair tends to benefit from deep conditioning too - leave conditioner on with some heat for 5-30 minutes - that helps with softness. Using the oil treatments and some deep conditioning might help your silkier hair and your more-coarse hairs come closer to each other in flexibility and softness so your hair is easier to work with.
      If you use protein on your hair (peptides, amino acids, hydrolyzed proteins, etc.) don't put protein on the center-back except once in a while. If your usual cleansing or conditioning products contain protein, it might be best to switch them for protein-free products to avoid adding rigidity to your more-coarse areas.

      You might have to treat the more-coarse hair differently and detangle the different sections separately and get to know what the different areas of your hair like and don't like. But that pays off by becoming a familiar routine pretty quickly so you don't have to think about it all the time.

      If you suspect thyroid disease, you absolutely should get that tested. While you're at it, get your Vitamin D and Ferritin levels tested, those are common deficiencies and common causes of thinning hair - which also have relationships with how thyroid hormone works in your body. It's all connected. Here is a link about iron, Vitamin D and hair thinning: http://science-yhairblog.blogspot.com/2015/11/ferritin-iron-vitamin-d-and-hair.html (copy and paste if the link isn't active).

      If you have hard water - especially if you have begun to notice this difference in curl pattern more at the same time as a move to a new location - the hard water might be giving your hair more rigidity. In that case, chelating shampoos help remove minerals (Ion Hard Water Shampoo, Malibu Wellness Hard Water Shampoo). These can be harsh for regular use, but okay for occasional use. You might use distilled water to wash sometimes too - which won't add any minerals. Those things will often bring back some softness. Hard water can cause hair to feel more rigid and act more frizzy.
      I hope something in there is helpful! Good luck

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    2. Another possible cause for that dry/coarse patch in the back is physical damage. Sleeping on it (especially on cotton pillowcases), ponytails.. it also gets more sun/pollution exposure than the rest. I know I have to take extra care with that area, similar to the extra care I show my ends. I try to keep my hair flipped up on top of my pillow, and use a satin case.. consistent oil treatment (a little every night before bed only on the trouble spots).. never use a standard pony holder (either a thick, soft scrunchy or a claw clip), watch out for barrettes too.. I also never brush it, I use my fingers usually with oil or conditioner for slip.

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