Published on June 10th, 2020
Whether your baby was born with a full head of hair, or you waited weeks to see those first sprouting tufts, your heart now fills every time you ruffle those soft locks. You notice more growth at every bath time, and as the weeks go on, you get a glimpse of the way your baby will look in the weeks and months to come.
But a baby’s hair color can change over time. You yourself may have gone from blonde to brunette or from dark brown hair to light during your childhood. So as more locks grow in, the question that’s always hanging is, “What color will my baby’s hair be?”
How Hair Color Works
Hair has a simple structure composed of three critical parts: hair shaft, hair cuticle, and hair bulb. The hair shaft is the visible part of the hair that protrudes from the skin. The hair shaft is anchored just beneath the skin’s surface thanks to the hair follicle. At the base of the hair follicle sits the hair bulb, which is where living cells divide and create the hair shaft. One type of cell inside the hair bulb directly impacts hair color:
- Melanocytes– Melanocytes are melanin-producing cells that affect bodily pigments including skin, eye, and hair color. This is why they’re often called pigment cells. They are present throughout the body, but it’s the melanocytes at the base of the hair bulb that give the hair shaft their color. As people age, the melanocytes in their hair bulb die, leaving hair shafts gray.
Melanocytes inject the melanin (or pigment) into keratinocytes, which are cells that create keratin. Keratin is the protein that makes up hair, skin, and nails. The melanin that’s inside the hair’s keratin is how hair gets its color.
There are different types of melanin that can change the color of hair:
- Eumelanin is the most prevalent melanin in the human body. This results in black and brown tones and gives pigment to both skin and hair.
- Pheomelanin results in red tones. This melanin is present not only in hair but also gives our lips their pink hue.
What Makes Hair Color What It Is?
Hair color is determined by the amount and type of melanin produced by melanocytes. While eumelanin dictates how dark the hair is, pheomelanin controls how red the hair is.
- Someone with dark brown or black hair has up to 95% eumelanin in their hair follicles. However, that doesn’t mean they lack pheomelanin. This lighter, red pigment may be covered up entirely under dark hair, or it may give brown hair a reddish hue in some lights.
- Blonde hair occurs in people who have little eumelanin—but don’t have much pheomelanin, either.
- People with red hair have more pheomelanin than eumelanin. The amount of eumelanin does affect what type of red hair. Auburn hair, for example, has more eumelanin than strawberry blonde hair, which has more eumelanin than fiery red hair.
The whole spectrum of hair color from champagne blonde to fiery red to charcoal black can be explained by the levels of these two varieties of melanin.
Genetics and Their Role in Hair Color
Hair color is polygenic—meaning, multiple genes interact to create an individual’s coif. Put simply, genes impact how much of each type of melanin is produced within the hair follicles.
One gene in particular—the most well-understood gene impacting hair color—is MC1R, which is involved in the creation of a protein called the melanocortin 1 receptor. The melanocortin 1 receptor determines which kind of melanin (eumelanin or pheomelanin) melanocytes produce at the root of the hair bulb.
As you may recall from high school biology, genes come in alternate forms (called alleles). These MCR1 alleles work together to form hair color:
- Most people have two functioning MC1R genes (one from each parent). When this gene is “on,” it stimulates the production of eumelanin. Having two functioning alleles is so common, 90% of people have brown hair.
- Some people have one MC1R gene that is “off.” This deactivated gene results in less production of eumelanin. This can result in lighter shades of hair, like blonde hair.
- If both copies of the MC1R gene are off, this results in little to no eumelanin production. Should there be an abundance of pheomelanin, people with this genetic profile will have red hair.
Mentioned above, this is just one gene out of many that determine hair color. Scientists have found up to a dozen genes that play some role in a person’s locks—though the individual gene’s level of involvement is still being understood.
Why Does a Baby’s Hair Color Change?
When your baby is born, he is now exposed to a new source of energy. The sun. This new source may affect his eye color[MS1], skin tone (e.g., tanning), and his hair color.
But it’s not straightforward why sunlight would cause your baby’s hair to darken over time. After all, sunlight’s UV radiation is known to bleach hair by oxidizing melanin and stripping its color.
While we don’t fully understand the reasons why light hair tends to darken over time, scientists theorize that changing hormone levels regulate the production of both eumelanin and pheomelanin, increasing the amount of eumelanin produced over time.
When Does a Baby’s Hair Color Change?
Similar to when a baby’s hair texture changes, when a baby’s hair color will change can depend on a few factors. Babies’ hair can change color through their first few birthdays. Though, by the age of 5, most children will have their adult hair color. However, in some cases, continued eumelanin production can increase over time, darkening hair well into adolescence.
So when does a baby’s hair change color? It’s hard to say exactly when. But the factors involved include: genetics, sun exposure, and nutrition (though genetics play the most significant role). As your child’s hair changes over months and years, you’ll go on a journey of discovery together.
The Truth About Dominant and Recessive Genes
You may have learned in high school that traits like hair color, eye color, and more are determined by dominant and recessive genes. For hair color, the theory goes:
- Each parent carries two alleles (gene variants) for hair color. Blonde hair is a recessive gene and brown hair is a dominant gene.
- A brunette may have two brown hair alleles or one brown allele and one blonde allele. However, a blonde person must have two recessive blonde genes.
- If two brunette parents both have a recessive blonde gene, there’s a 25% chance they’ll each pass down their recessive gene, resulting in a blonde child.
- Because blonde people carry only the recessive blonde genes, they can only have blonde children.
However, as you now know, it’s more complicated than that. After all, this “Punnett Square” model only considers the alleles that regulate the amount of eumelanin produced (MC1R). It doesn’t acknowledge the SLC7A11 gene which controls pheomelanin production and red hair, or any other genes.
Because more than one gene is involved in hair color, a simple theory of dominant and recessive traits doesn’t quite capture the whole picture.
How to Tell If Baby’s Hair Color Will Change
You might want to know if your baby’s hair will stay the same beautiful ashy blonde or chestnut brown for life. The most telling answer is locked away in the baby’s genes. To unlock this, you need a simple DNA test.
That’s why SneakPeek will be introducing the SneakPeek Early Traits DNA Test in the fall of 2020. This easy, at-home test requires only a quick rub of your child’s inner cheek with a cotton swab. From there, send the cotton swab back, and in 2-3 weeks, you’ll learn what your baby’s “adult hair” color will be (as well as other incredible insights). Taking the DNA sample is completely pain-free. And your child’s data is privacy-protected.
To give you a sneak peek at what you’ll discover, you can learn your baby’s eventual height, eye color, and even learn about her development, like her unique sleep and nutritional profile. With Traits, you’ll have more information at your disposal to help your growing baby live her best life. So, if you’ve been trying to answer questions such as, will my baby’s eyes stay blue or how tall will my child be, try one of our Traits tests this fall to find out.
Get All the Answers with SneakPeek Early Traits DNA Test
As a parent, information is power. The more you know about your baby, the better you can continue to nourish him and plan for his future. The SneakPeek Early Traits DNA Test can help you understand your child’s developing needs, as well as offer fun insights into his eye color, iris pattern, left-handedness vs right-handedness, and yes, his hair color too.
WebMD. Picture of the hair. https://www.webmd.com/skin-problems-and-treatments/picture-of-the-hair – 1
Genetics Home Reference. Is hair color determined by genetics? https://ghr.nlm.nih.gov/primer/traits/haircolor
The Journal of the European Academy of Dermatology and Venereology. Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin. https://www.ncbi.nlm.nih.gov/pubmed/22077870
Stanford @ The Tech. Other traits. https://genetics.thetech.org/ask/ask180
Photochemistry and Photobiology. Spectrophotometric Methods for Quantifying Pigmentation in Human Hair—Influence of MC1R Genotype and Environment.
American Journal of Physical Anthropology. Sex and genetic differences in hair color changes during early childhood. https://europepmc.org/article/med/1167738