How do Hair Dyes Work Chemically?

JurnalPost.com – Hair dye is a beauty product that young and old people often use. Based on research, around 50-80% of women and 10% of men use hair dye in the world. Hair dye is usually used to beautify hair or cover gray hair. But have you ever thought about how hair dye works so that it can change hair color? Did you know that the color change involves a chemical process?

Before discussing the chemical processes that occur, we should know the structure of our hair. Hair dye involves the hair shaft, so I will focus on the hair shaft. The hair shaft is made of keratin protein, which is one of the components that make hair strong and does not break easily. Three layers make up the structure of the hair shaft. The medulla is the inner layer. The cuticle is the outer layer, and the cortex is the second layer. The majority of the hair shaft is composed of the cortex. The cuticle is a dense layer of overlapping scales that resemble shingles. The cortex is the main part of the hair shaft that contains pigments, which give hair its color. Meanwhile, the cuticle is the outer protective layer of the hair shaft that covers the cortex.

Hair can be colored with pigment through the natural process of melanin production by melanocyte cells in the scalp. The melanin produced is then distributed into the hair shaft as the hair grows, giving the hair its color. Hair has two various kinds of melanin proteins: pheomelanin, which gives hair its reddish-yellowish color, and eumelanin, which gives hair its black-to-brown color. Gray or white hair is caused by a lack of color.

Ammonia and hydrogen peroxide are the two main chemical constituents of hair color. Known by many names as an oxidizer or developer, hydrogen peroxide prolongs the life of color and aids in its development. It oxidizes the melanin pigment found naturally in hair, eliminating some of the conjugated double bonds that give the molecule its color and rendering it colorless. The sulfur that is released when peroxide breaks down the chemical connections in hair is what gives hair dye its distinct smell. A new permanent color is attached to the hair cortex when the melanin undergoes a color change. The more developers used, the more sulfur will be extracted from the hair. Loss of sulfur causes hair to stiffen and weigh more. Ammonia catalyzes the reaction between peroxide and permanent hair color. Ammonia swells the hair cuticle, allowing dye molecules to penetrate the hair and create permanent color. In the presence of hydrogen peroxide, it can also help lighten your natural hair color.

Developers comprise an oxidizing agent (often hydrogen peroxide), and colorants contain two different kinds of molecules known as dye intermediates and coupling agents. When exposed to oxidizing chemicals, paraphenylenediamine (PPD), one of the most widely used primary intermediates, becomes extremely reactive and generates color molecules. But PPD alone is limited to producing a shade of dark brown. To achieve various colors, coupling agents, also known as couplers, are added to the hair dye mixture. They don’t seem to be dyeable on their own, but they can react with primary intermediate molecules to create a range of hues when used as hair dye. The concentration of the couplers controls how light or dark the color is.

There are three types of hair dyes: semi-permanent, permanent, and temporary, according to the American Cancer Society website. The dye temporarily coats the surface of the hair but does not penetrate the hair shaft. Usually, this kind lasts for a wash or two. The hair shaft is penetrated by the semi-permanent dye. Lasts 5–10 washes on average. A long-lasting chemical alteration in the hair is brought about by the permanent hair dye.

Behind the beautiful results of hair dyes, there are some dangers posed by them. Permanent hair dyes containing ammonia and peroxide can damage your hair, making it weaker, more prone to breakage, and thinner. Paraphenylenediamine (PPD) can also cause allergies in some people. Inhaling the chemicals in hair dye can cause coughing, wheezing, pneumonia, sore throats, and asthma attacks.

It has been demonstrated that the chemicals in hair color, known as aromatic amines, can cause cancer in laboratory animals, mainly when the animals are exposed to high concentrations of the dyes over extended periods. Women who use chemical hair straighteners and permanent hair dye have a higher chance of breast cancer than women who do not use these products, according to research by Carolyn E. Eberle and colleagues. The cause is that endocrine-disrupting substances, which are carcinogenic and can result in breast cancer, are present in a lot of hair products.

Coloring your hair without bleaching it is a safer way to avoid some of the risks mentioned above. However, be aware that coloring your hair without bleach can damage your hair even if done incorrectly. Therefore, it is important to choose high-quality hair color products and use the correct coloring method.

By: Aulia Febi Nugraheni, Universitas Pendidikan Indonesia

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