hair science
Curly hair science delves into the biological and structural characteristics that make curly hair behave differently from straight hair. The shape, growth pattern, and behavior of curly hair are determined by a combination of genetics, the structure of hair follicles, and the chemistry of the hair strand itself.
Hair Strand
Hair cuticles are the outermost layer of the hair strand, acting as a protective shield. The cuticle is made up of overlapping, scale-like cells that lie flat against each other, much like shingles on a roof. This layer helps protect the inner parts of the hair shaft, including the cortex and medulla, from damage caused by heat, chemicals, and environmental factors.
Hair Follicles
Curly hair originates at the root, where the shape of the hair follicle plays a key role. Curly hair follicles are asymmetrical or oval-shaped, as opposed to round follicles that produce straight hair. This shape causes the hair to grow at an angle, making it curl as it exits the scalp. The tighter the curl, the more oval the follicle.
Sebum Distribution:
Curly hair tends to be drier than straight hair because the natural oils, or sebum, produced by the scalp have a harder time traveling down the twists and turns of curly strands. This is why curly hair is more prone to dryness and frizz and requires more moisture to stay hydrated.
High porosity vs Low porosity
Hair porosity refers to how well your hair absorbs and retains moisture. The difference between high porosity and low porosity lies in the structure of the hair’s cuticles and how they interact with moisture:
• Cuticle Structure: The cuticles in high porosity hair are raised or have gaps, making the hair more open to absorbing moisture but also losing it quickly.
• Moisture Absorption: Hair with high porosity absorbs moisture very easily because the cuticles are more open, allowing water and products to enter the hair shaft.
• Challenges: While it can soak in moisture quickly, it also tends to lose moisture just as fast. This can lead to dryness, frizz, and breakage.
• Causes: High porosity hair is often a result of damage from chemical treatments, excessive heat, or environmental factors, but some people naturally have high porosity hair.
• Care: Use moisturizing products, heavier creams, or oils to help seal in moisture. Protein treatments can also strengthen the hair and fill in gaps in the cuticles.
High Porosity Hair:
• Cuticle Structure: In low porosity hair, the cuticles are tightly closed and smooth, making it harder for moisture to enter.
• Moisture Absorption: It is resistant to absorbing moisture because the tightly packed cuticles act as a barrier, preventing water and products from easily penetrating the hair shaft.
• Challenges: Low porosity hair can feel product build-up easily, as products tend to sit on top of the hair rather than absorbing. It can also take a long time to dry and may feel stiff or dry if not moisturized properly.
• Causes: Low porosity hair is often genetic and is not typically caused by external damage.
• Care: Use lightweight, water-based products or heat to open up the cuticles slightly, allowing moisture to penetrate. Deep conditioning treatments with heat can also help.
Low Porosity Hair:
Understanding your hair’s porosity helps you choose the right products and techniques to keep your hair healthy and moisturized