Effect of photodamage on the outermost cuticle layer of human hair

Assessment of hair surface roughness using quantitative image analysis

“…Human hair is composed of various biological structures. [1][2][3][4][5][6][7][8][9] Hair fiber has a hierarchical structure such as cuticle and cortex. 10 Hair cuticles are the outermost tissues to which commercial hair care products are first applied and protect the medulla and cortex from various external damage.…”

“…10 Hair cuticles are the outermost tissues to which commercial hair care products are first applied and protect the medulla and cortex from various external damage. 3,4 Hair cuticles are widely known as the penetration pathways of cosmetic ingredients into the inner hair and are closely correlated with changes in hair luster and texture. The positive effects of cosmetic ingredients applied to the head are first evident as changes in the cuticles.…”

“…However, the cuticle is the region affected first by stress caused by the external environmental and physical factors. [1][2][3][4][5][6][7][11][12][13] Healthy hair has glossy and smooth hair cuticle and undamaged outer layer, while unhealthy hair has dull and dry cuticle with rough outer layer. [6][7][8]14 People use various hair care products to maintain healthy hair or improve damaged hair.…”

In Vitro Methodologies to Evaluate the Effects of Hair Care Products on Hair Fiber

“…This could be applied to access certain hair strain properties, such as overall appearance [19]; particle deposition over surface and affinity to incorporated ingredients in hair care products [20]; structural and morphological changes [6,21,22]. This technique enables one to see samples with opalescent to opaque appearance, to amplify images and to measure composing parts [5].…”

“…Protein loss [11,12,[44][45][46][47][48]; Electrophoresis [13,25]; Scanning Electron Microscopy [5,[19][20][21][22]; Transmission Electron Microscopy [6,24,25]; Atomic Force Microscopy [7,26,[28][29][30][31]; Optical Coherence Tomography [8,33]; RAMAN spectroscopy [10,[32][33][34] Hair Shine-Gloss Diffuse reflectance spectrophotometry [14,33,43,46,50] Easy to comb Combing resistance [12,64,65] Strength properties Resistance to breakage [12,14,16,33,61,62] Photoprotection Photoluminescence spectroscopy [40][41][42][43] Long-lasting color Diffuse reflectance spectrophotometry [14,…”