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With a century's experience in black & brunette hair coloring, Hoyu can help you obtain a better understanding of hair for more effective coloring in your future.

Hair Structure

Hair Structure

Cuticle is the outer layer of hair shaft, which is made up of overlapping transparent keratin cells. It works like protective scales. Each cuticle cell is composed of several different layers such as A-layer, exocuticle and endocuticle. It is resistant to chemicals and protects cortex from chemical influences.

Cortex is where moisture and natural pigment (called "melanin") are held. No other part of the hair shaft has pigments. Melanin contained in cortex determines the natural color of your hair. Some hair color products, especially when lightening hair, work on melanin. Melanin is missing from gray hair.

Medulla is the core of hair shaft. Sometimes the medulla is absent from hair, and it's not yet scientifically clear why this happens.

Cuticle, the outer layer of the hair shaft, defines smoothness and shininess - because it can be seen and touched. Hair (cuticle) may get damaged by chemical processes, overexposure to sunlight (UV), too much heat from a dryer, abusive brushing and combing, over-chlorinated swimming pool water, etc.

Damaged hair/cuticle should be treated well with conditioners because cuticle cannot repair by itself once it is damaged.

Surface of Hair - Cuticle

Healthy Vs Damaged Hair Cuticle 

Hair-Type and Coloring Result Tendency

Just like fingerprints, hair type is unique to each individual. We have soft, medium, hard, thick, coarse, straight, curly, damaged, colored hair - with numerous combinations of all of the above! Also, natural (original) hair color and level of brightness (which is determined by melanin) varies greatly. There is black, brunette, red, blonde, and variations within each. Even when it comes to black hair color, there are many variations.

Your coloring result is influenced by hair-type and beginning color. If your hair is fine and soft, and your natural color is light, then it is more likely to be influenced by chemical actions and will color stronger than expected. If your hair is hard and thick, and your natural color is dark, then it is less likely to be influenced by chemical actions and will color weaker than expected.

In addition, color tends to deposit more strongly initially, then fades away more quickly onto damaged or color-treated hair. Virgin hair is more resistant to coloring.

Care - After Coloring

Good hair care is recommended on a daily basis, because your hair cannot repair itself without your help. Additionally, coloring results last longer with good hair care habits.

Hair Rinse Diagram

Rinse Just After Coloring

It is recommended to rinse hair thoroughly until water runs clear before shampooing. If hair is not well rinsed after coloring process, it may cause hair damage and color fading.

Hair Conditioner Diagram

Conditioner for Color-Treated Hair

Conditioners designed for color-treated hair or with a pH value of 3 to 4 are recommended. For a while after coloring, some of your cuticles won't close as easily as they did before coloring. The designed conditioner will expedite cuticle closure and prevent hair-damage and color-fading.