“Evaluation of the risk assessment of the hair dye ingredients: an update”
The use of hair dyes is a choice of millions of people today owing to coverage of grey hairs or cosmetic reasons. The hair dye products represent the most reactive chemicals that are in use in cosmetic industries and consist of a large number of chemical ingredients including 1,3-diaminobenzene, toluene-2,5-diamine sulfate, or p-phenylenediamine (PPD), m-aminophenol or resorcinol, ammonia or ethanolamine, hydrogen peroxide (H2O2) etc. The application of these substances may result in local exposure (eyes and skin) or systemic exposure by penetration through the skin. Thus with increasing use of hair dyes, there is a need to address the side effects that are associated with its use. Global concern raised by ammonia vs ammonia free hair color makes a great deal of publicity. Ammonia plays a very important role in assisting hair color to penetrate the hair strand easily and thus it is responsible for hair color’s ability to alter hair color hue without washing out. Hair coloring most often requires the use of ammonia which is considered essential for permanent hair coloring formulations. Ammonia is used at a concentration of less than 2% in EcoColors, where it is associated with no or almost negligible side effects. Whereas ammonia free hair color typically contain an ammonia substitute ethanolamine such as mono-, di- and trimethanolamine. Odorless nature of ethanolamine makes them more charming among the consumers and professionals comparative to ammonia. However due to large size ethanolamine can’t penetrate the hair more efficiently than ammonia and therefore is limited in lightening effects on hair. Thus non ammonia hair colors are less effective than ammonia based hair.
Ethanolamines are organic compounds that are aminoalcohols and characterized by the presence of amino group and hydroxyl groups that impart them a unique role in a wide variety of applications. They include monoethanolamines (MEA), diethanolamines (DEA) and triethanolamines (TEA) and are represented by the chemical structure as H2NCH2CH2OH, HN(CH2CH2OH)2 and N(CH2CH2OH)3 respectively. They are basic in nature, clear, colorless and viscous liquids that give off ammonia like odor. However, some forms of ethanolamines (monoethanolamine) display toxic, flammable and corrosive characteristic features. Nevertheless, due to the presence of two functional groups they can be used as various derivatives and thus find a wide range of applications in domestic as well as industrial purposes including gas sweetening in refineries; as detergents; pharmaceuticals; personal care products (soaps, shampoos, hair color, skin care and skin cleansing products etc.); in textile processing and metalworking etc. and cosmetic formulations as emulsifiers, thickeners, wetting agents, detergents, and alkalizing agents.
Monoethanolamine, MEA is the chemical swapped in for the ammonia. This ingredient is mainly used in semi-permanent color at about 3% concentration and for permanent color; the concentration has to be increased to 9%, compared to 1.8-3% of ammonia whereas the permissible level according to safety measure is 5%. Ethanolamine is an ‘adhesive’ type chemical, which is not completely washed out of hair and off scalp. After hair color with ethanolamine-based products, the water acts as a mild oxidizer during each wash of hair, inflicting further hair damage, fading and gradual dryness. Some forms of MEA receive a “high hazard” score in the Environmental Working Group’s Skin Deep Cosmetic Safety Database because it too may be associated with skin irritation and asthma and is classified as a “possible human immune system toxicant” by the National Library of Medicine. “Plus, MEA eventually degrades into ammonia,” says Cora Roelofs, ScD, an industrial hygienist in the Department of Work Environment at University of Massachusetts at Lowell. There are also reports that indicate induction of dermatitis and hair loss through oxidative stress and epidermal inflammation via use of MEA in the hair dye products. A wide range of effects have also been observed among hairdressers exposed to the ingredients, such as loss of fertility, growth retardation or developmental defects and congenital defects.
Diethanolamine (DEA) also as an ingredient of hair dye acts to diminish hepatic stores of the essential nutrient choline that play important role in neurogenesis/ brain development. Its dermal administration during pregnancy diminishes neurogenesis and increases apoptosis in the hippocampus of fetal rats and mice. The National Institute for Occupational Safety and Health estimates that the number of workers potentially exposed to DEA is ~ 800,000/year. Long-term toxicity studies of DEA by the International Agency for Research on Cancer found an association between an increase of liver and kidney tumors in rats and mice model. Clinical skin testing of TEA and cosmetic products containing TEA and DEA showed mild skin irritation in concentrations above 5%. Triethanolamine and Diethanolamine form cancer-causing nitrosamines when they come upon contact with nitrates and are toxic when absorbed on a long-term basis. Thus, don’t get fooled by the ammonia free hair colors. Ethanolamines are not only expensive but also toxic and damage the hair to a great extent. Because of their odorless nature, they are even hard to be detected. Take every necessary action to remove these hazardous ingredients from your day to day lives and remain healthy by being careful for your beauty.
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