The cuticle is the part of the hair that probably concerns us the most on a day to day basis. When our hair emerges from our scalp, it has about 6 to 10 layers of cuticle about 50 micrometres on a side and about 0.5 micrometres thick. The cuticle is attached to the cortex and forms a tight sheath around it. The cells of the cuticle overlap - often times likened to roof tiles - at about a 5Лљ angle and point downwards to the ends of the strands.
If the mechanical properties of our hair are determined by the cortex, then the optical properties of our hair is determined by the cuticle. Shine is determined by how the light catches your hair strands - if your hair is curly or wavy, it won't shine as much as straight hair. Shine can be a determination of the state of your hair - if it's dull looking, you might have build up or might be using the wrong conditioning agents - and sometimes it's not - if you have wavy, frizzy, curly, or generally non-straight hair.
Products from China and Italy have no cuticle. There is no point in removing the cuticle from good Remy donor hair. The cuticle is removed from cheap hair where the scales don't run in the same direction (tangled hair). The cuticle is the protective layer of hair - this is their skin. Hair without the cuticle don't shine because after having been treated with acid, the surface of a hair is not smooth, its friable. Hair like that won't catch the light and look dull. That's why Chinese manufacturers treat hair with silicone and iron them. After 3-4 washes the silicone wears off and then you'll know what Chinese quality is all about.
We make all our extensions of Remy donor hair and, in order to keep the cuticle intact, we dye hair very gently. In the end, this is what determines the quality of your hair extensions (easy to comb, shiny and elasticity).