A common topic that I hear about in my conversations with hair stylists and salon patrons is about moisture. What I usually tell people is that the moisture in African descent hair is significantly less than in Caucasian and Oriental (i.e. Mongol descent) hair. One reason for such deficiency of moisture could be the twisted ribbon-like structure of the African descent hair. The other reason for the deficiency of the moisture in African descent could be that the sebaceous glands within the African scalp are often less active and secrete inadequate amounts of sebum--the body's own natural brand of conditioner and hair-dress.
Therefore, the hair and scalp are relatively dry because there is less natural oil to be distributed down the hair shaft. Also, whatever oil that is secreted may find it harder to travel down the hair shaft because of the strands' excessive curliness, thus further contributing to dryness. The lower moisture contents of African descent hair may be a significant contributor to its relative fragility and will require future research.
Contrarily, Caucasians tend to have hyperactive sebaceous glands, hence the widespread practice of daily shampooing and the usage of stronger shampoos that contain less conditioning agents.
