Human Hair is a protein fiber made of two layers. The inner layer called cortex contains melanin. Melanin is a pigment which gives your hair shades of blonde, black, auburn or brown. Cortex is covered by another layer called cuticle. Cuticle provides protection to cortex and luster to your hair. Cuticle is inert in nature so it cannot biologically or chemically absorb any color.

Mechanism of Hair Dyeing

By Chemical Dye:

Most of the chemical dyes contain bleaching agents such as Ammonia and/or peroxide which damage the outer most layer and create capillaries in hair shaft. Then PPD, OPD, MPD like chemical color fills these capillaries, enter in inner layer and stay stick as permanent color. The next application again does the same on hair shaft. This results in loss of strength, roughness and permanent damage to hair.

By Natural Dye:

Natural Dye colors hair by coating the hair shaft. It provides thickness to hair and stick as a semi permanent color. The next application again does the same and results in increase in strength and shine in your hair.