It all begins with understanding the structure of your hair. Its’ ability to absorb substances and retain it.
The hair cuticle is the outermost part of the hair shaft. It is formed from dead cells, overlapping in layers, which form scales that strengthen and protect the hair shaft. While the cuticle is the outermost layer, it is not responsible for the color of the hair.
The cortex of the hair shaft is located between the hair cuticle and medulla and is the thickest hair layer. It contains most of the hair's pigment, giving the hair its color. The major pigment in the cortex is melanin, which is also found in skin.
The medulla is the innermost layer of the hair shaft. This nearly invisible layer is the most soft and fragile, and serves as the pith or marrow of the hair.
Understanding your hair structure leads to knowing your hair porosity.
Porosity is three categories: Low, Medium and High
Low porosity is hair that doesn't readily absorb water and treatments. Your hair may be low porosity if it takes a long time to wet and dry. If you use hair care products, they tend to stay on the surface of your hair rather than being absorbed. This hair type will benefit from heat to assist in absorbing products. The cuticle layer lies very flat. This makes the hair more resistant to absorbing water and other substances. Think of the hair shaft cuticle like French windows. In low porosity hair the windows (cuticle) are shut closed, they refuse to let moisture in, but once it does it holds on to the moisture to prevent it from escaping. With this type of hair you need ingredients which are small molecules and very light weight oils.
Medium "normal" Porosity: Your hair cuticles are spaced "normally" and let moisture pass and absorb without issues. Medium strands have looser cuticles, leaving spaces where moisture can enter. The cuticle like windows are half open, they don’t lie flat but are slightly raised. This hair type finds products easily to absorb into the hair shaft. You can fall between low/medium or medium/high porosity.
High porosity means that the cuticle has large gaps allowing moisture to enter seamlessly, however, the hair is unable to retain the moisture that is able to penetrate the hair fiber. Just like the windows example the cuticle of this hair type is wide open. Meaning it absorbs moisture quickly, but does not retain it. So this hair type needs, more protein and heavier oils. They benefit greatly from the LCO method.
To find your hair porosity is a simple test.
Get a glass of water at room temperature, not hot, not cold.
Next take a few strands of clean hair, note: no product should be on the hair. As we have different porosity all over our head. Take hair from the front, middle and back.
Place the strands in the water. If the hair:
Sinks to the bottom you are high porosity.
Stays in the middle you are medium porosity
Floats on top of the water you are low porosity.
The average of the strands position should tell you your porosity.
Knowing your hairs’ porosity is the first step towards healthy hair.