Permanent hair coloring technology about to be transformed
Posted Mar 08 2011 12:00am
ACS.org - Technological progress may be fast-paced in many fields, but one mundane area has been left almost the same, chemically speaking, for the last 150 years: the basic technology for permanently coloring hair. That’s the conclusion of an analysis of almost 500 articles and patents on the chemistry of permanent hair dyeing, which foresees much more innovation in the years ahead, including longer lasting, more-natural-looking dyes, gene therapy to reverse the gray, and hopefully safer alternatives to current beauty products for hair. The article appears in ACS’s journal Chemical Reviews.
Robert Christie and Olivier Morel note that hair dye already is a multibillion dollar international industry, poised for even greater expansion in the future due to the graying of a global population yearning to cling to appearances of youth. Most permanent hair coloring technology, however, is based on a 150-year-old approach that uses p-phenylenediamine (PPD), a chemical that produces darker, browner shades when exposed to air. Concern over the safety of PPD and other hair dye ingredients, and demand for more convenient hair dyeing methods, has fostered an upswing in research on new dyes and alternative hair coloring technologies. [Recent studies have raised questions about the risk for lymphoma and bladder cancer related to recurrent use of or exposure to hair coloring agents.]
The scientists describe progress toward those goals. Future hair coloring techniques include nano-sized colorants, for instance. Composed of pigments 1/5,000th the width of a human hair, these nanotechnology pigments will penetrate the hair and remain trapped inside for longer-lasting hair coloration. Scientists also are developing substances that stimulate the genes to produce the melanin pigment that colors hair. These substances promise to produce a wider range of more natural-looking colors, from blond to dark brown and black, with less likelihood of raising concerns about toxicity and better prospects for more natural results. Other new technologies may stop graying of the hair or prevent its formation altogether, the scientists say.
The full informative review of hair structure and hair dyeing is available here:
Chem. Rev. Publication Date (Web): January 25, 2011. DOI: 10.1021/cr1000145