There are also shades of grey, red, blonde and brown! All crummy jokes aside, chemical reactions determine hair color (be it natural or artificial). While there are many different shades of hair color, they only come from two kinds of melanin. Artificial hair coloring used while dyeing hair is a different story, and consists of a different kind of chemistry.
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Melanin is a term used to describe pigments, not just in hair follicles, but any pigment found in organisms. Melanin and the sun have a role in why your hair might change color, or what makes your skin become tan. When a person is albino, it means that they lack melanin. Melanin absorbs UV light, and can cause your hair (or skin) color to change.
The chemistry of hair color is partially broken down into two forms of melanin. One is pheomelanin, responsible for red hair and pinkish pigments. The other is eumelanin, which creates dark pigments like brown or black. To understand how proportions of these work, we can look to natural hair colors.
Dark, nearly but not quite black hair and brown, can all be associated with eumelanin, though in brown hair very small amounts of pheomelanin might be present. Red shades clearly have mostly pheomelanin. Lastly, similar to the white hair found in albinism, gray hair also suffers from a lack of melanin.
Hair dye does affect the chemistry of hair color. But, how do you change your hair color when you want? Does the process have an effect on melanin?
How do hair dyes work?
Hair coloring came into practice in 1909, and today it’s very common to see people testing out different hair colors and shades. Before the modern formula for hair coloring was invented in 1909, natural ingredients were used to color hair. There’s no evidence that the use of such plants are somehow safer than the chemicals found in hair coloring.
Natural coloring, however unsafe or not, only truly makes it through a few washes. Temporary hair color lasts longer than natural coloring, but runs on the same idea. Hair coloring “dyes” the hair, or puts a temporary hair color on the outside of the hair shaft.
For those unfamiliar with their hair anatomy, lets take a look.
Through your hair bulb, distends your hair root. If you’re familiar with hair coloring you probably have an idea about hair roots, since they frequently need to be touched up when they’re uprooted. In between the hair bulb and its root is the hair follicle wall and the sebaceous gland. The sebaceous gland secretes sebum, you might have too much secretion if you find your hair to be oily. It’s purpose is for protection and acts as a lubricant.
You can break down your hair anatomy into four parts. Your veins and the area before your bulb is the subcutaneous layer. Your bulb and everything up to your roots are the dermis, the epidermis consists of the hair before it comes out of the skin, and lastly, there is your hair shaft, the visible hair on your head. With temporary color, the outside of these follicles are dyes.
There are more permanent variations of hair color, and the chemical reactions involved are much different. Something I regularly heard about the chemistry of hair color as my sister attended cosmetology school is that bleaching hair prior to applying dye would lead to better results (not where the health of her hair is concerned, but it did look good).
The effects of bleaching hair are permanent. By permanent, I mean that the chemical reaction that occurs in this process cannot be reversed, or “washed out”. This consists of the process of oxidation. Oxygen is added, oxidizing the hair, and removing its color. What’s fascinating about this is it had no effect on the amount of melanin: the proportions are equal to whatever you started with. This too only affects the hair shaft, but instead of just the outside, the hair shaft is bleached through and through.
Permanent hair color is often used with bleach. This too goes inside the hair. Some permanent hair color removes the current color, and replaces it with the new on its own. I have never seen one that did that, I was always a witness to the bleach and color process. Peroxide is also used in permanent hair color, as its typically used as a tool in bleaching.
Science plays a huge role in beauty products, not just with hair coloring but from your mascara to your lipstick. Learn about STEM approved products on the site!
If you’ve learned enough facts about hair dye, or you’re anything like me and a huge fan of chocolate, you can learn about the chemistry behind chocolate!