Have you asked yourself (or me) one of these questions, 'Am I overdoing the moisture by washing/moisturising daily or am I overdoing the oiling by applying oil every night? '
Well the answer is...........it is complicated. It really depends on you and your hair. There is a case for water and one for oil. Here is the case for water
Hair is approximately 10% water and can easily absorb and lose this water. Water gets into hair and causes separation of the keratin (hair protein) molecules. This increases the pliability of hair meaning the hair is less rigid and is able to move/bend easily. (Journal of Cosmetic Science, pg 355-368, 2001)
The level of moisture in hair depends on one key factor – the humidity of the air (Journal of the Society of Cosmetic Chemists, 447-470, 1972). If the air is dry, water can be lost from the hair and if the air is very humid, hair will absorb water.
Secondary factors that can affect the amount of water include things like heat treatment which can drive alot of moisture from hair. In fact heat treated hair cannot go back to its original level even in humid conditions. It has to be re-wetted with water. (Journal of the Society of Cosmetic Chemists, pg 27-36, 1981)
Another secondary factor is porosity (Journal of Investigative Dermatology Symposium Proceedings, pg 2–5, 2007) – (read more on porosity)
So is there a benefit to using water/water based product to add moisture to your hair?
From the research above, I would think so. This is probably most useful if where you live is not particularly humid. There is one article which does point out though that consumers doing the touch and feel test really cannot tell the difference between different levels of hair hydration. (Journal of Cosmetic Science, pg 527-535, 2003).
Is there a case against wetting the hair?
Yes there are potential issues
1. Hygral fatigue – wetting the hair and then letting it dry and repeating the process several times causes the hair to swell and relax repeatedly which can damage the hair (Journal of Cosmetic Science, pg169-184, 2001).
2. Cuticle damage – Cuticle can lift due to wetting and can then subsequently be chipped during combing (Journal of Cosmetic Science, pg 327-339,1999).
Remedies to potential issues
1. Before washing - Use a penetrating oil (such as coconut oil) to limit the swelling of the hair.
2. After washing - Use an oil film to slow down moisture pick up from the environment around you (Journal of Cosmetic Science, pg135-145, 2007).
3. In between washing – Your hair probably does not need to be soaking wet to be moisturised, less is more.
So now that you’ve heard the case for water, click here to go to part 2 - the case for oil!