Both my middle and youngest daughters were born with thick, jet black hair.  My middle daughter had very thick, coarse and black hair as a young child. And the youngest daughter had very fine and black baby hair with big waves at the tip, like a doll.  But as they grew older, the color and texture of their hair changed, around the ages of 9 – 11 years old.  Both the girls’ hair changed color from black to brown, as with the texture. The middle girl’s hair texture changed from coarse to super fine and the youngest girl’s hair changed from super fine to frizzy and super curly!

My youngest daughter with super fine and black hair when she was a toddler.

Her hair turned frizzy and curly (sometime even kinky curly) when she was about 8 or 9 years old. The color changed from black to brown.

Why Did My Girls’ Hair Change Texture And Color?

Hair and eye color are mostly determined by our genes. But it’s not just by the genes we have, but also by whether those genes are turned on or turned off. And since genes can turn on and off throughout our lives, this means your hair color can change!

Many different factors can turn hair pigment genes on and off. These factors are not even completely understood by scientists.

Changes in hair color in kids and teenagers are most likely due to changing hormones. Hormones are chemical signals that the body uses to send messages between body parts. Changes in hormone levels can cause pigment genes to be turned on or turned off.

Hair colors can change well into puberty, as some genes aren’t “switched on” until the hormones flood the body in adolescence. Eventually, usually in the 30s, human hair stops producing melanin and begins to turn grey. Basically, it stops adding color to the hair. Gray hair tends to occur earlier in Caucasians and later in Asians.

This can happen in adults too.  Hormonal changes aren’t limited to puberty. Changes in age, nutrition, temperature, sun exposure and various other factors can cause our bodies to change the amounts or types of hormones we make.

The color of your hair is the product of a mixture of eumelanin (produces brown and black colors) and pheomelanin (produces red and yellow colors) in your hair. The amount of each type of melanin is typically unique to your genetic make-up – as is when those amounts will change and you’ll start to go grey.

What Else Can Change Hair Color?

Our hair color can change in ways unrelated to our genes. Harsh chemicals such as bleach and chlorine can change the chemical makeup of our hair. This can make our hair change colors.

When you go to the salon or bleach your hair, you are exposing your hair to very reactive chemicals. The main ingredient in hair bleach is hydrogen peroxide. When you put hydrogen peroxide on your hair, it reacts with the melanin pigments and makes them colorless. Hydrogen peroxide reacts faster with eumelanin than pheomelanin.

There are several other theories as to why hair changes color – sun exposure, medications, illnesses and hormones.

One theory is the sun’s UVB and UVA rays are being absorbed by your hair roots and the vitamin D has gone inside your scalp and it is sort of tanning your hair. Lots of direct sunlight will lighten anyone’s hair.

Usually, our hair will turn darker because eumelanin production increases as we age (until we go gray, that is). And because some genes are not switched on until triggered by the hormones first released during puberty, we might not show our “true” natural hair color until adolescence.

Hair is not the only feature to naturally change color as you age – for 10 to 15 percent of people, their eyes do too.

Can Hair Texture Change Too In Children?

If you’ve seen a baby or toddler’s soft hair and how it changes over time, similar changes also happen later in life. Around puberty, straight hair can turn wavy and its texture can change, or wavy hair may turn curly or kinky.  Coarse hair can change into fine hair too.

Why do these hair changes happen? 

A few hormones—thyroxine, triiodothyronine, androgen and insulin have been identified as the culprits behind these hair texture turnarounds. As a youngster’s body hits puberty, these hormones kick in and begin changing hair as well. Hormones also can impact hair growth.