Why is Hair Curly? The Science & The Tea

Virgy GachuruHair TypesLeave a Comment

why is hair curly

You’ve had a bad hair day, where your curly hair is just unruly and you’ve probably asked yourself; why is my hair so curly?

“Couldn’t I have been born with straight hair!”


No judgement here, really. I have to admit that curly hair can be ‘tricky’ to manage sometimes.

In this article we are going to look into the SCIENCE behind Curly Hair, to satisfy your curiosity once and for all.


Why is Hair Curly?

Here are 4 possible explanations as to why hair is curly:

#1. The Follicle Anatomy

Hair follicles are a group of specialized cells located within your skin. It is through the hair follicle that your hair grows.

Hair follicles can be straight, leading to the occurrence of straight hair or curly, leading to the emergence of curly hair. [1]

Curly follicles often have a bent elliptical shape; hence the hair shaft itself becomes curly. 

Scientists believe that this is caused by the way the cells in the curly hair follicle divide.

Unlike in straight hair, the cells in curly hair divide in an asymmetrical way, creating an elliptical shape that gives you curly hair. 

Therefore, your hair is so curly because the hair follicles are curly with a bent elliptical shape.

#2. Development and Molecular Controls

We initially saw that curly is determined by the shape of the follicles but what really determines the shapes of the follicle?

Is there a scientific explanation?

Certainly yes.

Stay with us as we divulge this further.

Despite not being studied in detail, it’s believed that your first hair cycle is somewhat different from the other hair cycles.

A good example is with babies of African descent who are born with curls that are loose and silky. But with time, their hair changes and they lose the silky curls as they grow older.

Scientists have therefore concluded that embryonic developments determine the shape of the follicle for the first cycle of hair growth but other developmental factors come into play as we grow older. [2]

As an adult, there are different developmental controls that will determine the shape of your hair such as:

  1. Asymmetrical Keratin structure. Certain hair Keratins are asymmetrical in structure, if you have these then you will likely have curly hair
  2. The orientation of the cortical cells and the Keratin filaments in relation to the hair growth axis
  3. Size and shape of the papilla

#3. Genetic Traits

Everything boils down to your genetic make-up.

This explains why curly hair is more prevalent is certain races or regions of the world.

Basically, your hair is curly because you inherited the curly genes from your parents.

Secondly, scientists believe that Trichohyalin (TCHH) may affect the way hair curls. [3]

TCCH is a gene that is found in the hair follicle and sometimes the hair shaft. In simple terms, if you have the TCCH gene you are more likely going to have curly hair.

#4. Adaptation

Another interesting angle to look at the curly hair phenomenon is adaptation.

From an evolution assumption, curly hair came about as a result of the body adapting itself to provide scalp cooling and UV protection. [6]

This could (just maybe) explain why Africans have very curly/coily hair to offer protection from the sun.

Take this with a grain of salt as this as has not been studied extensively.

Is Curly Hair Rarer Than Straight Hair?

According to numerous studies conducted, curly hair is rarer than straight hair. [7] 

About 15% of the world’s population has curly hair.

Almost all ethnicities have been noted to have curly hair, but the incidences are lower among Europeans and Asians.

Majority of the people with curly hair are those of African ancestry. 

Can Curly Hair Become Straight?

Curly hair can temporarily or permanently become straight when techniques such as heat and Keratin treatments are applied.

Although, the shape of your hair follicle doesn’t change (except with a medical condition) and therefore new hair grows curly.

The following techniques have been used to straighten curly hair with varying degree of effectiveness.

#1. Use of heat

This involves the use of equipment such as a flat iron or a blow dryer that uses heat to change your hair’s texture.

This particular technique has temporary results and you have to keep using it to maintain straight hair.

When straightening with heat, here are some tips to take into consideration:

  • Use heat protectants to protect your hair from the heat
  • Include deep conditioning in your routine to restore your curls
  • Use low or cool heat settings
  • Using techniques such as the chase method to avoid direct heat on your strands

#2. Japanese straightening 

Also known as thermal reconditioning, this is a lengthy process that involves loosening protein bonds in the hair shaft.

Be forewarned this treatment can be damaging in the long run.

#3. Chemical straightening

Otherwise known as hair relaxing, this is the most common way to straighten curly hair.

The method results in permanent straight hair although the new growth retains it’s original curl pattern hence why, you will need to maintain a retouch routine.

With the natural hair movement, the use of chemical relaxer had significantly gone down but has slowly started to resurface thanks to hair influencers suddenly going back to texturizers.

As always, do your homework before you decide to go with this option.

#4. Keratin treatment

Keratin treatment doesn’t completely straighten your hair, but it makes it easier for you to style and manage it.

If done properly techniques such as heat straightening can be safe but be careful as some may damage your hair. Please do your homework.

PS: On this site, we embrace the uniqueness of our hair. Curly hair is beautiful, wavy hair is beautiful, straight hair is beautiful. We are by no means encouraging you to alter your curl pattern.

Bottom Line: Why is my Hair So Curly?

Your hair is curly because:

  1. You have curly hair follicles
  2. You inherited it from your parents
  3. It’s probably an adaptation
  4. There are molecular controls that are causing your hair to be curly

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