Hair color

“Hair color” leads to this page. See Equine coat color for information on horse hair color. See Hair coloring for colorants for hair.

Human hair color

Human hair color spectrum: clockwise from top left: black, brown, blonde, white, red.

The pigmentation of human hair follicles caused by the two forms of melanin—pheomelanin and eumelanin—is what gives people their hair color.

In general, hair is lighter when melanin levels are lower and darker when melanin levels are higher. The ratio of yellow or red pheomelanin to black or brown eumelanin determines the hair’s tone.

A person’s hair color can change over time due to variations in melanin levels, and many colored hair follicles can exist on the same person individual.

Certain ethnic groups link to specific hair colors because those colors are more common in that geographic area.

For example, people often associate straight dark hair with East Asians, Southeast Asians, Polynesians, and Native Americans; Europeans, West Asians, and North Africans with a wide range of dark, fair, curly, straight, wavy, and bushy hair; Sub-Saharan Africans with curly, dark, and uniquely helical hair; and aging with gray, white, or “silver” hair.

Genetics and biochemistry of hair color

Also see: Genetic variation in humans and Genetics and race

Hair color originates from a complicated and incompletely understood genetic basis. In general, scientists believe that regulatory DNA plays a significant role in human pigmentation.

A 2011 study by Branicki et al. found 13 DNA polymorphisms across 11 different genes that might be used to predict the color of hair.

The two pigment types that give hair its color are reddish-brown/reddish-yellow and black-brown eumelanin. Pheomelanin, which melanocytes produce. The melanocytes convert tyrosine into L-DOPA and then into L-dopaquinone to form pheomelanin or eumelanin.

The human population’s differing ratios of these two pigments give birth to different hair color phenotypes, however Europeans exhibit the widest variation of pigmentation overall.

Human hair color can also be influenced by additional genetic and environmental factors.

For example, red or auburn hair can result from mutations in the melanocortin 1 receptor (MC1R) gene, and UV radiation exposure can damage hair and change its pigmentation.

UV radiation also increases the production of melanin in the skin, which helps to protect it from UV radiation. Melanin also helps to absorb light, which helps to regulate the circadian rhythm of animals.

People who live closer to the equator typically have darker hair because eumelanin is generally more photoprotective than pheomelanin. UV radiation is mostly emitted by the sun.

Pheomelanin gives red and orange hues to hair. Darkness of hair color is determined by two subtypes of eumelanin: black and brown.

More black eumelanin results in darker hair, and more For browner hair, use brown eumelanin. Some amount of both pigments are present in all human hair. Eumelanin makes up more than 95% of the melanin found in black and brown hair.

Blond and red hair usually contain a higher amount of phenomelanin, which makes up approximately one-third of total melanin. Strawberry blonde is the outcome if there is no black eumelanin. There is no black eumelanin in blonde hair, only trace levels of brown eumelanin.

Natural hair colors

Color shade scale

Physical anthropologists and physicians use the Fischer-Saller scale for evaluating hair color shades. The scale employs Roman numerals I to IV (red) and V to VI (red blond), as well as the following designations: A (very light blond), B to E (light blond), F to L (blond), M to O (dark blond), P to T (light brown to brown), and U to Y (dark brown to black).

Black hair

The deepest hair color is black. It is more dense than other hair colors, contains a lot of eumelanin, and is widely available.

Brown hair

After black hair, brown hair is the second most frequent hue in humans. Higher amounts of eumelanin and lower levels of pheomelanin are characteristics of brown hair. Brown-haired people have brown eumelanin, which is different from black eumelanin.

They also typically have medium-thick hair strands. Usually, brunettes are European, West Asian, or North African women or girls with brown hair.

As the name implies, chestnut hair has a reddish-brown hue. Chestnut has a deeper reddish-brown color than auburn hair. Native populations in Asia Minor, West Asia, North Africa, and Northern, Central, and Eastern Europe all frequently have chestnut hair.

Auburn hair

The hues of auburn hair vary from pale to deep reddish-brown. Eumelanin (brown) and pheomelanin (red), with a greater percentage of the red-causing pheomelanin than is typical for brown hair, are the chemicals that form auburn hair.

Although it is present in North Africa, West and Central Asia, and individuals of Northern and Western European origin are the most common places to find it. A mutation in the melanocortin 1 receptor gene may possibly be the cause.

Red hair

Red hair can be titian, copper, or bright red. It can also be light strawberry blond. Red hair typically has low levels of eumelanin and the largest percentage of pheomelanin, roughly 67%. It is the least common hair color in the globe, accounting for only 1% to 2% of the west Eurasian population.

It is primarily found in Udmurtia and the British Isles. Scotland has the largest number of redheads, with 13% having red hair and 40% having the recessive gene for redheads. A number of North American, South American, and East Asian countries also have red hair. It is less common in other regions, such as Asia and Africa.

Blond hair

Blond hair can range from pale white (platinum blond) to dark gold blond (occasionally blonde for women). Strawberry blond hair is the most pheomelanin-containing variety of blond or reddish-blond hair.

[Reference required] Though it contains just trace amounts of both, blonde hair can have nearly any ratio of pheomelanin to eumelanin.

Pheomelanin produces golden or strawberry blond hair, whereas eumelanin produces ashy or sandy blond hair.

While most of Europe, as well as smaller numbers of West Asians and North Africans, can find it, people most frequently associate blonde hair with Northern and Northeastern Europeans and their descendants.

Research conducted in 2012 revealed that a recessive mutation in tyrosinase-related gene causes Melanesians’ naturally blonde hair TYRP1 (protein 1).

The gene is absent outside of Oceania, although it is present in 26 percent of the population in the Solomon Islands.

Gray and white hair

Here, “white hair” redirects. See White Hair for the Native American leader. See White hair for the fictional figure.

The absence of melanin and pigmentation is what causes gray or white hair, not a real gray or white pigment. A transparent hair appears gray or white due to the way light reflects from it. As people age, gray hair usually appears spontaneously (see aging or achromotrichia below).

Deficits of vitamin B12, Waardenburg syndrome, and thyroid problems can occasionally cause gray hair. The cells at the base of the hair follicles slow down and eventually stop releasing pigment at some point during the human life cycle.

One uncommon autosomal dominant disease of melanocyte development, which could result in a white forelock at birth, 867

While Asians start graying in their late 30s, Europeans often start growing gray hair in their mid-30s. Most Africans, on the other hand, don’t start graying until their mid-40s.

It is possible to inherit white hair for life beginning in childhood; nevertheless, unlike albinism, there are no detrimental effects on health. Because heredity transmits the feature as X-linked recessive, it appears more prevalently in men; nonetheless, carriers may not experience any symptoms.

Graying is a gradual process; according to L’Oreal research, 74% of people between the ages of 45 and 65 have some gray hair overall, which covers an average of 27% of the head. Approximately 1 in 10 people did not have any gray hair at all, even after the age of sixty.

According to a theory known as “Marie Antoinette syndrome,” stress is the reason behind unexpected whiteness. It has been discovered that when stress is reduced, some hairs can change color once more.

Conditions affecting hair color

Aging or achromotrichia

Certain children may notice a progressive darkening of their hair as they grow. Babies with red, blonde, or light brown hair frequently go through this.

Genes that are activated and inactive between early childhood and puberty are the reason of this.

A man, forty-one, with somewhat gray hair

As people age, their hair usually naturally changes color, eventually becoming gray and then white. We refer to this as achromotrichia. In most cases, achromotrichia starts in the late 20s for women and the early to mid-20s for men.

By the time they turn 40, more than 60% of Americans have some gray hair. The onset of graying appears to be largely genetically determined. Some people acquire this characteristic and have gray hair from birth.

The sequence in which graying occurs frequently is: facial hair, body hair, beard, nose hair, and eyebrow hair.

In contrast to the skin, which continuously creates pigment, the stages of the hair cycle strongly link to melanogenesis in the hair. The hair actively pigments during the anagen phase, while it becomes nonexistent and can’t color on either end during the catagen and telogen phases.

The same man, now fifty-six, had his hair completely gray

Bcl2 and Bcl-w became the first two genes identified as responsible for graying, and researchers identified the IRF4 (interferon regulatory factor 4) gene in 2016 as an additional factor.

6,000 residents of five Latin American nations participated in the study. Nonetheless, it discovered that almost 70% of cases of hair graying were determined by environmental variables.

When melanin production in the hair root stops and new hairs grow in without pigment, the color of the hair changes. Melanocytes, the cells that create and store pigment in skin and hair, are produced by stem cells found at the base of hair follicles. Graying starts as a result of the melanocyte stem cells dying.

Why one hair follicle’s stem cells might stop activating more than ten years before those in neighboring follicles spaced less than a millimeter away is still a mystery.

The buildup of hydrogen peroxide and excessively high levels of low concentrations of catalase, an enzyme that reduces hydrogen peroxide and helps vitiligo sufferers with oxidative stress,.

A similar mechanism may cause aging-related hair loss on the head (and other places), as vitiligo can cause white eyelashes. [Untrustworthy source?]

Recent research has demonstrated that the anti-cancer medication imatinib can reverse the graying process.

It is not practical to use to change someone’s hair color, though, because it is costly and has possibly dangerous side effects. It may be possible to develop a less costly and safer alternative medication in the future by understanding how imatinib affects melanocyte stem cells. Imatinib may affect catalase, or there may be another reason why the graying process reverses.

Stress

Anecdotes suggest that stress—acute or chronic—may cause achromotrichia in people earlier than it otherwise would have.

Proponents include notable leaders like Bill Clinton and Barack Obama, as well as survivors of tragedies like John McCain, a prisoner of war, and Harold Bride, a survivor of the Titanic.

Though no conclusive evidence has been provided, there is some indication that prolonged stress can lead to early achromotrichia.

In human hair, the stress hormone cortisol builds up over time; however, it is unclear if this influences hair color.A 2020 study published in the journal Nature suggested that stress might contribute to hair color loss.

In those with black hair, an excessive immune response can kill melanocytes and melanocyte progenitor cells.

They faded their coat when they purposefully caused them to fear. Since these injured follicles lacked melanocyte stem cells, white hairs appeared and the color loss was irreversible when the rats’ coat grew again.

UV damage

The most frequent cause of structural damage to the hair shaft is excessive sun exposure. Photochemical hair damage includes both deterioration of the hair pigment and loss of hair proteins.

A prevalent practice among those of European descent is photobleaching. In a recent 23andMe study, over 72% of participants with European ancestry who consented to participate in the research stated that the sun lightens their hair.

Additionally, 48 genetic markers that may affect hair photobleaching have been found by the company.

Medical conditions

from melanin. If the right diet is followed, the problem can be cured.

Premature graying can also result from pernicious anemia and Werner disease.

An uncontrolled study conducted in 2005 showed that people aged 50–70 who have dark eyebrows but gray hair have a considerably higher risk of type II diabetes than people who have both gray hair and eyebrows.

Artificial factors

According to a 1996 British Medical Journal study, smoking tobacco may hasten the onset of graying of the hair. It was discovered that smokers had a four-fold higher risk of experiencing early graying in comparison to non-smokers.

Alopecia caused by electron beams, inflammatory processes, and some chemotherapy regimens can all cause gray hair to momentarily turn darker. There is still a great deal to learn about the physiology of human graying.

Despite the fact that many have promoted them over the years, researchers have not shown any particular diets, vitamins, minerals, or proteins to delay, stop, or otherwise impact the graying process.

But while administering the cancer-treating medication imatinib to leukemia patients, French researchers noticed an unexpected adverse effect: some of the patients’ hair color returned to its pre-gray state.

Changes after death

Buried bodies’ hair can change hue. A combination of reddish-yellow pheomelanin and black-brown eumelanin is seen in hair. Compared to pheomelanin, eumelanin is less chemically stable and degrades more quickly when exposed to oxygen.

In severe weather, hair changes color more quickly. When it’s dry, like when someone is buried in sand or ice, it changes more slowly than when it’s moist, like when someone is buried in wood or plaster coffins.

Hair coloring

Article focus: dyeing hair

A stylist applies color to a client’s hair.

Chemical processes can be used to alter the color of hair. “Permanent” and “semi-permanent” coloring techniques are used on hair.

When hair is permanently colored, it indicates that its structure has been chemically changed until it is finally removed. This does not imply that the artificial hue will last indefinitely. The procedure involves removing one or more hues of the natural color and replacing it with synthetic color.

Every pigment is removed from the cuticle. Artificial color fades the fastest, while natural color lasts much longer. (depending on the color molecules and the shape of the dye pigments).

Because permanent hair color may also make hair darker or lighter, it offers the greatest flexibility.

as altering hue and tone, but there are drawbacks. To address fading and ensure that newly developing hair blends in with the rest of the hair, regular maintenance (every six weeks or month) is necessary. One-color permanent dye produces a consistent, flat color on the entire head, which can appear harsh and unnatural, especially in light shades.

The current fashion to counter this is to employ a variety of hues, usually starting with one base color and adding highlights or lowlights in different tones.

The semi-permanent color fades over four to six weeks, making the regrowth of the roots less obvious.Each strand’s initial color and porosity will determine its ultimate color, causing slight color variations throughout the head that align more with nature.

and gentler than coloring that is permanent. Nevertheless, this implies that gray and white hair will not dye the same color as the remainder of the head .(some white hair won’t even take up the color). There will be a few white and gray hairs that mix in well enough to be undetectable, but as they spread, a semi-permanent will eventually be insufficient.

By utilizing a semi-permanent base color with permanent highlights, you can postpone the transition to 100% permanent color.

You cannot lighten hair using semi-permanent hair color. Only chemical lighteners, like bleach, can be used to lighten hair. Because bleaching eliminates natural pigment, it is always permanent.

The term “rinses” refers to the temporary hair color that we typically apply to hair when shampooing and remove the next time we clean the hair.

honey blonde hair dye

How can one achieve honey blonde hair? Before applying your nectar-inspired hue, your colorist will probably need to use bleach to lift your present color and create a blank canvas if you want honey blonde hair.

honey blonde hair dye

See also

Human skin tone