How the hair grows out of the follicle influences the distribution of its proteins. So a straight follicle produces straight hair and a curved follicle produces curly hair. The less evenly distributed the squiggly proteins are, the curlier the hair.
The shape of the hair follicle is the main factor that determines whether the hair is curly or straight, but hormonal changes, medications, aging, etc. can indirectly cause changes in hair shape by affecting keratin, the scalp environment, and the hair growth cycle.
Researchers suggest that the evolution of curly hair in early humans was a crucial adaptive trait in equatorial Africa, offering effective protection from the sun's heat and minimizing the need for sweating. This passive cooling mechanism likely allowed for brain growth by conserving water and reducing heat.
The shape of the hair follicle is the main factor that determines whether the hair is curly or straight, but hormonal changes, medications, aging, etc. can indirectly cause changes in hair shape by affecting keratin, the scalp environment, and the hair growth cycle.
Keratin is packed with the multiple copies of the amino acid cysteine which is comprised of a sulfur chemical group that allows it to bond easier with other sulfur containing molecules. With curly hair, there are disulfide bonds that form in the strands that brings the hair closer together forming the curl.
Fluctuating Estrogen Levels Can Bring About Changes in Your Curly Texture. Estrogen levels often fall for curl changes as estrogen is key for maintaining those helical hair follicles. During menopause, plummeting estrogen is linked to the onset of mixed curl patterns and gradual straightening of previously curly hair.
While the shape and placement of the follicle determines your curliness, it's the disulphide bonds that keep the hair holding on to its shape once above scalp level and exposed to the air. Both the quantity and placement of disulphide bonds affect the degree of curl.
During puberty, menopause and pregnancy, many people will find their will go from straight to curly or vice versa over a period of months. It's also interesting to note that even long periods of stress can be enough to change the texture of your hair.
All hair textures are biologically the same. Where they differ is in the actual shape of the fiber and the follicle. Curly hair is born deep in the scalp from a curved bulb, and takes its winding shape due to irregularly distributed keratin, the building blocks of hair.
Higher testosterone levels, like during pregnancy or as a natural part of aging, can cause straight hair to become wavier by changing the shape of hair follicles. Some women may experience the opposite effect, with curls loosening over time due to decreasing testosterone.
Genotyping results show that 94.9% of Black people have curly hair. Additionally, 12.7% of Europeans and 12% of Asian people have curls. Biracial hair is a complicated term, and it does not refer specifically to one hair type or shape.
Tightly curled scalp hair protected early humans from the sun's radiative heat, allowing their brains to grow to sizes comparable to those of modern humans.
Your hair is only mostly dead
A hair has two parts: the root and the shaft. The root is the living part of the hair that sits in the dermis, the middle layer of the skin. The root is surrounded by the follicle, which is typically attached to a sebaceous (oil) gland in the skin.
The gene for curly hair in Caucasians
A recent genome wide association scan has found a SNP (single nucleotide polymorphism) called rs11803731 in the TCHH gene which accounts for about 6% of hair curliness.
The curls stop the natural flow of oil down to the tips of the strand, preventing your hair from getting the adequate lubrication it needs for protection. The moisture barrier breaks and is unable to retain any moisture, which causes your hair to turn frizzy.
According to Curlkeeper, less than 20% of people have curly hair, making it a rare hair type. However, curly hair comes in all kinds of different styles starting with super coiled curls to slightly wavy. Curly hair requires work to maintain and take care of it, making it hard for some to stick to the routine.
So a straight follicle produces straight hair and a curved follicle produces curly hair. The less evenly distributed the squiggly proteins are, the curlier the hair. Your genetic code also plays a role in the shape of the cortex and, therefore, the shape and thickness of your hair.
Going back to a time when most of us roamed around half-naked, it has been suggested our pubic hair is curly because it does a better job capturing and holding the pheromones that are produced by our sweat glands.
70 Together with the evidence from studies of heat gain and loss in birds and nonhuman mammals, these findings suggest that short, curly, Afro-textured hair evolved because it can maintain a boundary layer of cooler, dryer air near the scalp, and thereby protect the thermo- genic and thermosensitive brain.
If you have straight hair, your hair may become slightly curlier as you age. This is because the shape of hair follicles changes over time.
From foam rollers and rag rollers to braids, buns, and pin curling, there are plenty of no-heat methods for creating curls. To enhance curls and ensure the style lasts longer, gently work in a curl-defining gel, spray, or mousse before rolling or pinning small sections of your hair into coils, buns, rags, or rollers.
The main hormones that determine the nature of your hair follicles are Thyroxine, Triiodothyronine, androgens and insulin. A lack of Thyroxine and Triiodothyronine can make hair feel dry and brittle. Whereas an increase in androgens are more closely connected to affecting shape.
Follicle Shape- The shape of your hair follicle largely determines your curl. Oval follicle shapes produce curly hair while round follicles produce straight hair. A flat oval shape will create kinky, coily hair. To help you visualize, think of a piece of gift-wrapping ribbon.
There is evidence that trichohyalin (TCHH) may affect hair curl in most/all world populations and that other genes such as EDAR and WNT10A only affect specific populations.
Curly hair may have evolved in early humans living in Africa thousands of years ago to help stay cool and protect from the sun's harmful rays, research suggests. Scientists found that tightly coiled hair provided a barrier against solar radiation to protect the scalp.