The porosity of hair is variable from head to head or even from roots to tips. People dealing with the extreme ends of porosity can have a hard time managing their hair. Which is why knowing what affects porosity can help you tackle your hair needs accordingly.
5 Factors that affecting the porosity of hair
pH has been known to have an impact on the level of swelling of the hair and on the cuticles themselves. Low pH causes the CMC (cell membrane complex) layer to contract and to maintain the cuticles flat. [Read more about the CMC layer and porosity here].
High pH does the opposite, causing the cuticles to be more lifted. These have direct impacts on how much water the hair takes or releases. In low porosity hair, using low pH products (< 7) will not help the hair to absorb more moisture. Instead, using a shampoo at slightly high pH (7.5-8) can help the hair to swell more. Finish with a low pH conditioner rich in humectants. On the other hand, if you have high porosity hair, avoid products with high pH. Sealing the moisture with products is the key here.
Heat will cause the fiber to swell. During showers, warmer temperatures helps the hair to swell more. This is great for low porosity hair. However, always finish on cool water rinses to bring down the swelling and keep the moisture in. If you have high porosity hair, you might want to remain on the cooler end of the thermometer throughout the showering period. The water doesn’t have to be cold, but avoid hot. [Read more about effects of hot water here].
Heat styling also causes the hair to swell. Regardless of how porous your hair is, heat styling will cause loss of moisture from the hair. Make sure to use a protective product before heat styling.
3. Chemical treatments
Chemical treatments such as coloring, perming etc. will have direct impacts on the structural integrity of the hair. The very high pH and oxidizing/reducing agents will damage the protective external lipids (18-MEA) of the cuticles, damage the protein of the hair, and damage the CMC layer (which is supposed to keep the cuticles down). With added swelling, more lifted cuticles and more protein loss, the hair’s porosity becomes very high. The level of damage varies from treatment to treatment but either way, the hair will need more conditioning to seal in moisture. [Read more about the importance of 18-MEA here]
4. Pool water
Chlorine has been known to have oxidizing effects on the protein of the hair. It can degrade the protein in the cuticles as well as those in the CMC layer. The proteins gets fragmented and are eventually lost. The damage inflicted here will also make hair more porous. [Read more about the effects of chlorine here]
5. Product build-up
Product build-up from for example heavy oils and insoluble silicones, can make hair appear low in porosity. The fact is that these hydrophobic materials behave like lipids. They have a tendency to repel water. They adhere to the hair cuticles and resist shampooing. Those suffering from low porosity hair should avoid using too much of these ingredients. [ Learn about water soluble silicones here]