We all know and, constantly hear how bad heat styling is for our hair. Unfortunately most of us can’t live without styling, whether it’s a blow dry, or flat-iron or curling iron… Here we will look at the impact of heat on the hair, and how we can protect the hair.
One study investigated the effects of flat-irons on hair after simulating multiple shampoo/styling treatments with hair tresses. These results corroborate the other theories on how heat affects hair. Obviously blow drying doesn’t have the same extent of damage as flat-ironing does. The temperatures used for flat-iron are usually 350F and above.
Damaging effects of heat styling on hair
- Damage to the hair surface. Cuticles become more rough because of the cracks, fissures, holes, micropores, etc. It is known that the boiling of water in the inter cuticle membranes creates holes in the cuticles. Eventually, cuticles are also lost leaving hair unprotected.
- The heat causes structural damage to the protein of the hair. Denaturing occurs. What that means is that the proteins, which usually exist as an α helical conformation, open up. This helical conformation is what gives the fibrous protein in hair its strength. Opening the proteins weakens the core structure of hair.
- Lipids and smaller proteins in the cell membrane complex are lost during heat styling. This also weakens the hair, and can cause the hair to feel drier and less pliable.
- The stress of combing hair (grooming) causes breakage because of the weakened internal and external damage on hair.
- Thermally damaged hair do not fully regain the moisture that they lost during heat styling. They also do not retain moisture well possibly because of the changes in protein structure and loss of lipids. What that means is that hair ends up feeling drier/coarser over time. The most damaged areas such as the ends will feel like straw over time.
Protecting the hair against heat styling
The study mentioned above were testing various protective polymers (VP/acrylates/lauryl methacrylate copolymer, PEC, polyquaternium-55 etc.) on the hair prior to flat-ironing.
They found that the polymers provided “protection to the hair surface and cortex resulting in reduced hair breakage during combing. The pretreatment of hair with selected polymers also improve moisture restoration and water retention of thermally treated hair.”
In other words, coating the hair with thermal protecting sprays provides benefits to the hair. The sprays can mitigate the damaging heat effects. It is obviously impossible to avoid all damage but conditioning the hair properly, caring for the split ends, using good shower practice etc. can all add on to preserving the hair integrity longer.