Have you ever wondered how some people could effortlessly switch their hair colour from blonde to brunette or rock a vibrant rainbow hue? How Hair Colour Works? Or you’ve been curious about how hair colour changes naturally over time, turning from luscious dark locks to silver strands. Well, the magic behind hair colour isn’t just about picking a shade from a box or letting nature take its course. A fascinating interplay of science, biology, and chemistry determines the pigments that give our hair its unique hue.
So, buckle up and get ready to embark on a journey to unravel the mysteries of how hair colour works and discover the captivating science behind this remarkable aspect of our appearance. From the genetics that determines our natural colour to the chemical reactions that occur during hair dyeing, we’ll delve into the captivating world of hair colour and unlock the secrets that make our locks a canvas for endless possibilities. Get ready to unravel the science of hair colour and embark on a colourful adventure!
Understanding the Basics: Hair Structure and Pigmentation
To understand how hair colour works, we must first understand the basics of hair structure and pigmentation. Hair is made up of a protein called keratin, produced by cells in the hair follicles on the scalp. These follicles also contain pigment-producing cells called melanocytes, which produce the pigment that gives hair its colour.
Hair pigmentation is determined by the presence and distribution of melanin, which provides colour to our skin, eyes, and hair. Melanin is produced by melanocytes, specialized cells located in the hair follicles and responsible for the synthesis and distribution of melanin into the hair shaft.
Melanin has different types, including eumelanin, black and brown, and pheomelanin, yellow and red. The proportion and type of melanin in the hair shaft determine the specific colour of the hair.
Factors Influencing Hair Colour
Several factors influence our hair colour, including genetics, ethnicity, and age. Let’s take a closer look at each of these factors:
Our genes play a crucial role in determining our hair colour. Hair colour is an inherited trait, and our genes from our parents can influence the type and amount of melanin our melanocytes produce. For example, if both of your parents have dark hair, you are more likely to have dark hair. However, genetics can be complex, and multiple genes can be involved in determining hair colour.
Ethnicity also plays a role in hair colour. Different ethnicities tend to have different hair colours due to variations in the genes that regulate melanin production. For instance, people of African descent tend to have dark hair, while those of Asian descent tend to have dark brown or black hair. On the other hand, people of Northern European descent often have lighter hair colours, such as blond or red.
Hair colour can also change with age. As we age, the melanocytes in our hair follicles may produce less melanin, resulting in a loss of pigment and a change in hair colour. This is why many people experience greying of hair as they age.
The Role of Melanin in Hair Colour
Melanin is the pigment that provides colour to our hair, and it is produced by melanocytes in the hair follicles. The amount and type of melanin in the hair shaft determine the specific colour of the hair.
Two main types of melanin determine hair colour:
- Eumelanin: Eumelanin provides dark colours, such as black and brown. It is responsible for the dark hair colour in black, brown, and dark brown people.
- Pheomelanin: Pheomelanin provides lighter colours, such as yellow and red. It is responsible for lighter hair colours, such as blond and red.
The proportion and distribution of eumelanin and pheomelanin in the hair shaft determine the hair colour. For example, hair with a higher proportion of eumelanin will be darker, while hair with a higher proportion of melanin will be lighter. The distribution of melanin in the cortex, the middle layer of the hair shaft, ultimately determines the visible hair colour.
The production of melanin in the hair follicles is influenced by genetics, as specific genes regulate the activity of melanocytes. These genes determine the type and amount of melanin produced, affecting the hair colour an individual inherits.
As we age, the activity of melanocytes can decrease, resulting in a reduction in melanin production. This can cause the hair to turn grey or white, as the absence of melanin results in a loss of colour in the hair shaft.
Various external factors, such as exposure to UV radiation from the sun, can also affect melanin production in the hair. UV radiation can damage melanocytes, leading to a decrease in melanin production and a change in hair colour over time.
In addition to determining hair colour, melanin protects hair from UV radiation and other environmental factors. Melanin acts as a natural sunscreen, absorbing and scattering UV radiation, which helps to protect the hair shaft from damage.
How hair colour work?
Hair colour is determined by pigments called melanins, produced by melanocyte cells in hair follicles. There are two main types of melanin: eumelanin, which is responsible for black and brown hair colours, and pheomelanin, which is responsible for yellow and red hair colours.
The hair colouration process begins during the hair follicle’s growth phase, known as the anagen phase. Melanocytes in the hair bulb, which is the base of the hair follicle, produce melanin and transfer it to the cells that form the hair shaft. The melanocytes’ amount and type of melanin determine the hair’s colour.
The genes inherited from our parents play a significant role in determining our natural hair colour. These genes control the production and distribution of melanin in the hair follicles. For example, if a person inherits genes for high levels of eumelanin, they are likely to have dark hair. In contrast, if they inherit genes for low levels of eumelanin and high levels of pheomelanin, they are likely to have light or red hair.
Environmental factors, such as exposure to sunlight and chemical treatments like hair dye, can also affect hair colour. Sunlight can bleach melanin, resulting in lighter hair colour, while chemical treatments can add or remove melanin to change the hair colour.
The hair shaft itself is made up of three layers:
The medulla, cortex, and cuticle. The medulla is the innermost layer and is not always present in all hair types. The cortex, which is the middle layer, contains most of the hair’s pigment, including melanin. The cuticle is the outermost protective layer of the hair shaft.
Hair colour can change naturally over time as we age.
As we age, the melanocytes in the hair follicles may produce less melanin, resulting in greying hair. The age at which this occurs and the greying rate is primarily determined by genetics.
In summary, hair colour is determined by the type and amount of melanin melanocytes produce in the hair follicles, which is influenced by genetic factors, environmental factors, and age.
What is the difference between hair colour and dye?
Hair colour and hair dye are related terms but not precisely the same. Hair colour refers to the natural colour of an individual’s hair, determined by the pigments in the hair shaft. Hair colour can be genetically inherited and vary widely from person to person, ranging from shades of black, brown, blonde, red, and even grey or white.
On the other hand, hair dye refers to a product or process used to change the colour of hair artificially. Hair dye typically contains chemicals that deposit colour onto the hair shaft, altering its natural colour. Hair dye is often used for cosmetic purposes, such as covering up grey hair, enhancing or changing the natural hair colour, or creating bold and creative looks.
The main difference between hair colour and hair dye is that hair colour is the natural colour of the hair that a person is born with or develops over time, while hair dye is an artificial colour applied to the hair using chemical products. Hair colour is determined by the amount and type of pigments (melanin) in the hair shaft. In contrast, hair dye is a temporary or permanent change to the hair colour achieved by using colourants that are not naturally present in the hair.
Another difference is that hair colour is typically more subtle and gradual, while hair dye can result in more dramatic and immediate colour changes. Hair colour can also change naturally over time due to ageing, hormonal changes, and environmental factors, while hair dye is an intentional change made using hair colouring products.
It’s important to note that hair dye can have potential side effects, such as hair damage, scalp irritation, and allergic reactions, due to the chemicals used in the colouring process. It’s essential to follow the instructions carefully and conduct a patch test before using any hair dye product to minimize the risk of adverse reactions.
In summary, hair colour is the natural colour of the hair, while hair dye is an artificial colour applied to the hair using chemical products. Hair colour is determined by genetics and can change naturally over time, while hair dye is an intentional change made using hair colouring products. Hair colour is typically more subtle, while hair dye can result in more dramatic and immediate changes.
In conclusion, melanin is the pigment responsible for hair colour and is produced by melanocytes in the hair follicles. The type and amount of melanin produced determine the specific hair colour, with eumelanin providing dark colours and pheomelanin providing lighter ones. Genetic factors, ageing, and environmental factors such as UV radiation can influence melanin production and hair colour.
Does colouring hair damage hair?
Yes, colouring hair can potentially cause damage to the hair, as the chemicals in hair dye can strip the hair of its natural moisture and protein, leading to dryness, brittleness, and breakage. Some hair dyes contain harsh chemicals such as ammonia and peroxide, which can further damage the hair cuticles and weaken the hair structure.
How long does hair colour last?
The duration of how long hair colour lasts depends on several factors, including the type of hair dye used, the colour of the hair, the condition of the hair, and how well the hair is maintained. Generally, permanent hair colour lasts longer, typically around 4-6 weeks, as it penetrates the hair shaft and lasts until new hair growth occurs. However, semi-permanent and temporary hair colour may fade after a few washes or weeks, as they do not penetrate the hair shaft and coat the hair.
What happens to your hair after colouring?
After colouring, hair may undergo several changes. These can include changes in texture, such as increased dryness or brittleness, and changes in colour, such as fading or uneven colouration. Hair may also require more maintenance, such as using colour-safe shampoos and conditioners and regular deep conditioning treatments to restore moisture and nourish the hair.
How is hair dye permanent?
Permanent hair dye uses chemicals that open the hair cuticle to allow colour molecules to penetrate the cortex, which is the innermost layer of the hair shaft. Once the colour molecules are inside the cortex, they undergo a chemical reaction that causes them to expand and become trapped, resulting in a permanent change in hair colour.
This is why permanent hair colour lasts longer and is more resistant to fading than semi-permanent or temporary hair colour, which only coats the outside of the hair shaft and does not penetrate the cortex.