Human Hair in History
Natural hair has been an outward sign of vibrant health and beauty. Natural hair communicates socially –without a word uttered. In the ancient dynasties of Egypt and China, mineral and plants were widely available and thus began the history of natural hair coloring with natural dyes. Desiring to improve their appearance and also cover gray hair, women have dyed their natural hair for centuries.
Scientific Hair Facts: What is Hair Made of?
In all mammals, natural hair develops as an epidermal structure from papillae deep in the skin and acquires characteristic patterns on the scalp, eyebrows, eyelashes, and elsewhere on the body. In humans, hair growth is continuous throughout life (declining with advancing age), occurs in cyclic patterns, and is influenced by androgens, thyroid hormones, and dietary factors.
Human hair is composed largely of keratin and consists of a narrow central medulla surrounded by a thick envelope (cortex) of elongate cells, which contain numerous melanin granules that determine the natural color. The hair is ensheathed in a multilayered cuticle of overlapping cells that become progressively imbricated (having edges overlapping in a regular arrangement) with continued growth. These cuticular cells are rich in cystine (disulfide bonds) and become rough or show a weathered appearance through exposure to environmental exposure or poor health.
While hair color is closely related to the density of melanin granules, impairment in a person's health or substances in the diet that influence the availability of trace minerals are potential causes of changes in hair color or condition. The configuration of the hair shaft (i.e., straight, wavy, spiral, or peppercorn) is attributable to the number and distribution of disulfide bonds. Hair straightening requires reduction of these disulfide bonds and fiber cross-linkages.*
Hair Facts: Why Gray Hair?
Melanin granules are secreted by melanocytes in the hair papilla and distributed to keratin in the hair cortex and inner layers of the hair sheath during normal development.
Two main forms of melanin exist in human skin—eumelanin and phaeomelanin, both of which are derived from tyrosine through the action of tyrosinase (a cupro-enzyme) and possibly other key enzymes (with nickel, chromium, iron, and manganese as cofactors).
Hair color is a balance between these two melanins. Albino or white-haired individuals have latent melanocytes. Graying of the hair is age-related and possibly results from declining melanocytic function or retarded hair growth resulting from atrophy or degenerative changes in hair papillae. Hair melanin absorbs insufficient ultraviolet (UV) light energy to afford protection for most individuals against sunburn.*
*see Chemistry Encyclopedia references:
Prota, G. (1988). "Progress in the Chemistry of Melanins and Related Metabolites." Medicinal Research Reviews 8:525–556.
Swift, J. Alan (1997). "Morphology and Histochemistry of Human Hair." In Formation and Structure of Human Hair, ed. P. Jollies, H. Zahn, and H. Höcker. Basel, Switzerland: Birkhäuser Verlag.
Swift, J. Alan (1998). Fundamentals of Human Hair Science. Cosmetic Science Monographs, No. 1, ed. H. Butler. Weymouth, U.K.: Micelle Press.
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Author: L.J. O'Neal, writer and researcher. (L.J. is also a Lustrous Henna® user.)
©2012. L.J. O’Neal. ALL RIGHTS RESERVED.
Do not copy or reprint this article without the consent of the author or Saba Botanical of USA.
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*Even though our herbal ingredients have been used in natural medicine for centuries, we must add the following disclaimer: The herbs, formulas, and recipes contained within this web site are not to be considered substitutes for proper medical and health care. As with any other medicine, if you are sick, you should consult a physician to find out if the herbal preparations listed here are right for you. Saba Botanical does not make any medical claims nor warranties regarding the use of the products listed on this site. No matter how natural a product is, it may have a potential of causing side effects and allergic reaction on certain individuals. You should consult your physician before taking any medication.
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