Understanding Hair Frizz
A: Hair frizz is caused by the disruption of your hair's outermost protective layer, known as the cuticle, combined with moisture changes in the inner core of the hair, known as the cortex. Think of the cuticle as overlapping shingles on a roof that, when lying flat and smooth, create a sleek, shiny surface. When these shingles become raised or roughed up, they create an uneven texture that we see as frizz.
Hair Frizz Triggers
The biggest trigger for raised cuticles is humidity in the air. On hot, humid days, water molecules in the air penetrate the cuticle and enter the hair’s inner cortex. This moisture temporarily breaks the weak hydrogen bonds holding your hair’s keratin proteins together, forcing them to reform into new, irregular shapes. As the inner core swells up with this trapped water, it forces the outer cuticle shingles to lift even further. This causes individual hair strands to bend away from one another and stick out as frizz.However, weather is only part of the story. Chemical treatments like coloring, perming, relaxing, or frequent bleaching strip away protective surface lipids and permanently chip the cuticle layer. Heat styling tools used without thermal protectants can boil the moisture inside your hair, roughing up the outer surface. Even friction (from aggressive towel drying, rough brushing, or sleeping on cotton pillowcases) strips away protective oils and roughens the hair shaft over time.
Genetic Traits
The reason why some people seem naturally blessed with smooth, manageable hair while others constantly battle frizz comes down to two genetic traits: hair shape and hair porosity.First, hair shape plays a massive role. Naturally straight hair has a round cross-section like a straw. Its flat outer shingles allow natural oils from your scalp to easily slide all the way down the hair shaft, keeping the whole strand coated and smooth. In contrast, wavy, curly, and coily hair grows from oval or flat-shaped hair follicles and this creates asymmetrical strands with raised cuticles at every turn of the curl. This asymmetry makes it harder for natural oils to travel down the hair shaft, leaving the hair drier and far more vulnerable to moisture fluctuations.
Second, genetics determine your hair's porosity. This means how tightly or loosely the outer shingles lay against the hair strand.
• Low-Porosity Hair: The cuticle shingles lie extremely flat and tight against each other. This creates smooth, shiny hair that repels humidity and resists frizz. Low-porosity hair resists hair products, dye, and water. This means it takes longer to get wet in the shower and a long time to dry.
• High-Porosity Hair: The cuticle layers are naturally lifted or pitted with gaps, making the hair quick to absorb ambient moisture and equally quick to lose internal hydration. High-porosity hair reacts constantly to environmental humidity, making it very prone to frizz. While it absorbs hair dyes and treatments easily, it is also far easier to damage.
• Medium or Normal Porosity Hair: The cuticles lie in a healthy balance, allowing controlled moisture absorption and retention without constant frizz.
While it is a popular method, dropping a strand of hair into a glass of water (the float test) is rarely an accurate way to test porosity. Things like product buildup or water surface tension often ruin the result. A better test is to spray dry, product-free hair with a mist of water. If the droplets bead up on top of the strands, the hair porosity is low. If the water absorbs almost instantly, the hair porosity is high.
©Hairfinder.com
See also:
How to tame frizzy hair
Dry and frizzy hair after blow-drying
Dry and frizzy hair after a sauna