The penetration of these chemicals can occur through 3 pathways
Why are plant stem cells important if I colour my hair?
1- The chemicals can penetrate through an intercellular lipid pathway. The stratum corneum consists of cells known as corneocytes. The spaces between the corneocytes are filled with lipids (fats). High pH chemical and products will attack and break down the lipids and allow cellular damage.
2- Another pathway for chemicals to be absorbed into the dermis is transcellular, or cell-to-cell, permeation whereby molecules diffuse directly through the corneocytes.
3- Lastly, chemicals can diffuse into the scalp is via rooted hair. The chemicals can diffuse down the follicle into the root where intercellular damage occurs.
How chemicals from colour and other treatments cause damage