How does melanin give hair its color?
A person’s natural hair color comes from the spread, amount, and combination of brown, black, and red melanin pigments . These pigments, color absorbing molecules, are expressed in melanosomes that come from melanocytes in the skin as shown in figure 1. The pigment then can be embedded in the hair shaft between keratin fibers giving hair the darker pigmented coloration . White or colorless hair results from the reduction in the concentration of the melanin pigments .
Natural Hair Dye Limitations
Hair color is associated with youth, health, and is a form of self-expression in our modern society. Some people aim to recover their natural hair color after a loss of coloration and some aim to deviate from their natural color. The concept and practice of hair coloring is recorded in the culture in ancient civilizations with natural sources of pigments from plants, animal byproducts, and even the use of microorganisms which have also continued to be used today such as the use of henna seeds, roots such as beet and tumeric, and coffee beans . With natural hair dye solutions, a frequent regimen for maintenance is required. These conflicts sustains the market to use synthetic treatments for long term hair dye.
Commercial Hair Dye Limitations
Studies have reported P-phenylenediamine (PPD), a coloring agent found in commercial dye, is related to skin irritation and cause allergic reactions . Some dyes contain toluene, a neurotoxin, causing similar adverse reactions as PPD. Some dyes use heavy metal salts associated with heavy metal poisoning in hair dye users . In addition to the coloring agent in many chemical hair dye treatments, preparation agents in the coloring process such as ammonia used to improve penetration of the coloring molecules and hydrogen peroxide used to lighten hair cause skin irritation . Some ammonia-free and PPD free options have been released however only tend to provide semi-permanent hair color that produce varying results. Still, the public continues to use commercial permanent hair coloring products for the longer-term results, convenience, and lifestyle compatibility.
How Synthetic Melanin Hair Dye May Be Used
A new color agent is being explored to eliminate harmful coloring agents and produce natural looking permanent color. In this study the methods included oxidizing dopamine to polydopamine to synthesize synthetic melanin nanoparticles . By using concentrations of 3-6% ammonia solution to oxidize the reaction along with heating at 37–40 °C (standard blow dryer range), even color darkening was achieved comparable to natural black and brown hair . The even coloration and pigmentation were comparable to commercial dye quality as well. Following peroxide treatments, shades can be lightened to reds and dark or light blondes. The study also concluded that the color lasted an 18-cycle wash period where the hair was washed 5 times with water then with 10% shampoo without fading or soiled water coloration compared as observed in the compared commercial hair dye samples . The final observation noted in the study showed compatibility for coloration of virgin, previously dyed hair, and greying virgin hair .
The use of synthetic melanin for permanent hair color could be a strong prospect in the commercial hair color industry. The processing time, efficacy, and simplified ingredients in the researched process could be the intermediate we are looking for in providing more natural looking, long lasting, and less harmful quick and easy hair coloring. However, this process is not ammonia free and does not include ingredients necessary to perform the very popularized and controlled cream application. In addition, shampoos and conditioning treatments included for commercial use may also contain additional ingredients that negate the simplification and minimization of harmful chemical benefits associated with this process. Further testing will have to be done skin tissues as well to ensure the risks associated with skin irritation and allergic reactions will not be associated with this product.
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