Question of the Week: What is hair porosity?

Hair Porosity

Hair porosity is the ability of the hair to hold and absorb moisture, hair products, and chemicals. Good porosity is important because it allows your hair to retain moisture, oil, and protein levels; thus, giving your hair a radiant look and feel. The degree of porosity is determined by the condition of the cuticle layer. The cuticle is made of overlapping keratin (protein) cells that lie closely on the shaft like fish scales. Knowing your hair’s porosity is important so that you can maintain a proper and balanced moisture level. Hair porosity is classified as resistant (low porosity), normal, or porous (high porosity).

Resistant/Low Porosity Hair

Low porosity hair has a tight, compact cuticle layer. The cuticle scales lie flat and overlap one another. Low porosity hair is often quite shiny and many experts feel that low porosity hair is generally healthy.  Chemical services (coloring and relaxing) performed on low porosity hair requires a more alkaline solution because chemicals are difficult to absorb because the cuticle is closed.

Low porosity hair requires products rich in moisture and emollients. It also benefits from products that contain humectants because humectants attract moisture to the hair and holds it there.

If your hair repels water when you wet it, you may have low porosity hair.

Normal Porosity

Normal porosity hair is neither resistant or overly porous. Normal porosity hair allows moisture to pass into the cortex as needed and resists too much water to penetrate. Normal porosity hair has a tendency to hold styles well. Chemical processes are usually performed in a typical and predictable manner, following the guidelines of the product.

Overly Porous Hair/High Porosity

High porosity hair is usually the result of damage to the hair’s cuticle layer. The damage causes gaps and holes in the surface of the hair shaft. High porosity hair has a raised cuticle that easily absorbs moisture because the cuticle layer is open.  Chemical services performed on overly porous hair require a less alkaline solution than low porosity hair.

Overly porous hair has a tendency to be dry because it releases moisture more frequently, it may also feel brittle and break easily. Protein treatments may be helpful for overly porous hair because it patches some of the holes in the cuticle; however, it must be followed with moisturizing products.

If your hair absorbs water easily and seems to drink up conditioner, you may have high porosity.

Porosity & My Hair

Knowing my hair’s porosity has made a tremendous difference in the way that I care for my hair. I have mostly low porosity hair, except for the portion of heat damaged hair that I continue to struggle with. My heat damaged hair section is overly porous, and I have to apply more product to that section than the rest of my hair. With protein treatments, apple cider vinegar rinses, and a porosity control shampoo, I have been able to guide that section to the light. I do not struggle with the porosity of that section as much as I used to. It is also possible that I may have simply given up and I now just go with the flow.

Once I realized that I had low porosity hair (when my hair is drenched in water, the water beads up on top), I started paying more attention to the ingredients in the products that I was using. I slowly learned that although my hair adored most humectants, glycerin was not my friend when the dew point was over 60. After I stopped using products with glycerin in high dew points, my hair completely turned around and no longer favored roadkill by the end of the day.

Naturals, do you struggle with your hair’s porosity?