Hair color is determined by the amount and type of melanin pigment produced in the hair follicles. Melanin comes in two forms: eumelanin which produces brown and black hues, and pheomelanin which produces red hues. The combination and ratio of these two pigments determine your natural hair color.
Human hair color is highly diverse, ranging from common shades like blonde, brown and black to rarer natural hair colors like red and gray. But what is the rarest hair color in America?
What Determines Hair Color?
Hair color is primarily genetically determined, although environmental factors can also influence hair pigmentation. The major genes that control hair color are:
- MC1R – regulates production of melanin
- OCA2 – associated with brown and blue eyes
- SLC24A4 – associated with light pigmentation
- SLC24A5 – associated with light pigmentation
- TYRP1 – associated with darker pigmentation
The most common genetic combinations result in brown, black, blonde and red hair. Rarer versions or mutations in these genes can produce unusual hair colors outside the normal human hair color spectrum.
Common Hair Colors in America
The most comprehensive study on hair color frequency was conducted by the National Health and Nutrition Examination Survey (NHANES) in the United States between 1999-2014. The NHANES study surveyed over 10,000 participants and found the following hair color distribution:
| Hair Color | Frequency |
|---|---|
| Blonde | 29.9% |
| Brown | 39.9% |
| Black | 11.3% |
| Red | 2.7% |
As shown above, brown is the most common hair color, followed by blonde, black, and finally red hair. Brown hair encompasses a wide range of shades from light brown to almost black. Blonde hair also includes many shades from nearly platinum blonde to dark blonde.
Rarest Hair Colors
While brown, blonde and black hair make up over 80% of natural hair colors, there are some very rare hair colors that occur infrequently in the population:
Strawberry Blonde
Strawberry blonde is often considered one of the rarest natural hair colors. It is a variety of red hair with golden or blonde highlights. The mix of blonde and red hair gives it a pinkish tint. Strawberry blonde occurs when an individual has two copies of a mutated MC1R gene that impairs melanin production and results in this distinctive hair color. An estimated 2% of Americans have naturally strawberry blonde hair.
Blue/Gray
Natural blue or gray hair is also very rare, occurring when an individual produces low levels of both eumelanin and pheomelanin. Blue and gray hair result from a graying or dilution of the natural hair color. Among caucasians, less than 1% have natural blue or gray hair. It is more common among those of European ancestry and is associated with aging.
Platinum Blonde
Platinum or almost white blonde is an extremely light shade of blonde caused by low levels of melanin production. Natural platinum blonde hair without bleaching or coloring treatments is very rare, estimated to occur in less than 1% of Americans. Those with natural platinum blonde hair tend to have European ancestry.
Green
Natural green hair in humans without color treatment is perhaps the rarest hair color. Green hair is caused by an accumulation of copper in the hair shaft. There are only a handful of documented cases of people with true green hair. The most well-known case was a doctor in the early 1900s who intentionally consumed silver for antimicrobial purposes, turning his hair green.
Rarest Hair Color Statistics
Here is a summary of the estimated frequencies of rare natural hair colors:
| Hair Color | Frequency |
|---|---|
| Strawberry Blonde | 2% |
| Blue/Gray | |
| Platinum Blonde | |
| Green | Extremely Rare |
While strawberry blonde hair occurs in an estimated 2% of the population, blue, gray and platinum blonde hair are significantly rarer at less than 1%. Natural true green hair is perhaps the rarest hair color that exists.
Causes of Rare Hair Colors
Some of the key genetic factors that lead to rare hair colors include:
- MC1R mutations – Variants in this gene reduce eumelanin production, increasing pheomelanin and leading to red hair colors.
- OCA2 and SLC24A4 variants – Mutations in these genes impair melanin synthesis, producing blonde and gray shades.
- Extremely low melanin levels – Some rare variants severely limit total melanin production, resulting in platinum blonde and gray hair.
- Pigment accumulation – Buildup of other pigments like copper can produce green hair.
Additional causes of rare hair colors include aging and environmental factors. But in most cases, it is uncommon genetic variants that produce these distinctive hair colors.
Geographic Distribution of Rare Hair Colors
Unusual hair colors appear to be more common in individuals of European ancestry, especially those from Northern Europe. This is likely related to genetic differences in melanin production:
- Strawberry blonde – Most prevalent in British and Irish populations
- Blue/Gray – Most common in Finland and among Scandinavians
- Platinum blonde – Occurs across Northern European groups
- Red hair – Associated with Celtic populations in the British Isles and Northern Europe
Rare hair colors seem to decline as populations live further south. For example, strawberry blonde, gray and platinum blonde are exceptionally uncommon in Africa and Asia.
Rarity of Colors Outside the Natural Human Range
Hair colors that fall outside the typical human range of shades are theoretically possible but have never been conclusively documented. These include:
- Purple – True purple hair does not occur naturally in humans.
- Pink – Natural pink hair has not been observed.
- Blue – Only appears sparsely alongside gray/white hairs.
- Green – Verified cases of natural green hair are extremely rare.
While many hair dyes and coloring treatments can produce these shades, human hair does not naturally grow in these colors. Genetic variants leading to these colors either do not exist or are incompatible with life.
Prevalence of Dyeing and Coloring
Most people with rare hair colors end up dying or coloring their hair later in life. A study by research company L’Oreal found:
- 75% of American women dye their hair.
- 50% of men in their 40s dye their hair.
- 25% of men and women start dyeing their hair by age 20.
This means that many individuals with naturally rare hair colors like platinum blonde and strawberry blonde cover up these shades as they get older. The prevalence of hair dyeing makes studying the epidemiology of rare natural hair colors even more challenging.
Conclusion
In summary, strawberry blonde, blue, gray and platinum blonde hair appear to be the rarest natural hair colors in the United States population. Green hair has been documented in only a handful of cases worldwide. While more research is needed, these shades occur distinctively from the typical human hair colors of blonde, brown and black.
The genetics influencing human pigmentation are complex and not fully understood. Additional mapping of genes involved in melanin production will likely uncover new causes for rare hair colors. But one fact remains certain – for those few who possess them, rare hair colors like strawberry blonde and platinum blonde are an unusual and special part of their appearance.