Why are some hairs thick and wiry?

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Hair is a fascinating feature of human biology. It is unique to our species and serves a variety of functions, such as providing warmth and protection, and even aiding in the regulation of body temperature. However, not all hair is created equal. Some individuals have thick, wiry hair, while others have fine, soft hair. This variation in hair texture is largely determined by genetics, but there are also other factors that come into play. In this blog post, we will explore why some hairs are thick and wiry, and what factors contribute to this unique hair type.

Why are some hairs thick and wiry?

Genetics and Hair Texture

One of the primary factors that determine hair texture is genetics. In fact, the genetic makeup of an individual largely determines not only the thickness and texture of their hair, but also its color and growth rate. Hair is made up of a protein called keratin, which is produced by hair follicles. The shape and size of these follicles, as well as the amount of keratin produced, determine the thickness and texture of the hair that grows from them.

Researchers have identified several genes that are associated with hair texture. For example, variations in the gene for the protein trichohyalin have been linked to differences in hair thickness and curliness. Another gene, called the EDAR gene, has been found to influence hair thickness, as well as other physical features such as tooth shape and sweat gland density.

While genetics plays a major role in determining hair texture, it is important to note that environmental factors can also influence hair growth and texture. For example, exposure to harsh chemicals or excessive heat can damage the hair and alter its texture. Hormonal changes, such as those that occur during puberty or pregnancy, can also affect hair growth and texture.

Ethnicity and Hair Texture

In addition to genetics, ethnicity also plays a role in determining hair texture. People of different ethnic backgrounds often have distinct hair types and textures. For example, individuals of African descent typically have hair that is tightly coiled and wiry, while those of Asian descent often have straight, fine hair.

These differences in hair texture are largely due to variations in the shape and size of hair follicles. In individuals of African descent, hair follicles are often curved and oval-shaped, which causes hair to grow in a tight, coiled pattern. This type of hair is often referred to as “kinky” or “curly.” In contrast, individuals of Asian descent have straight, round hair follicles, which produce hair that is typically straight and fine.

It is worth noting that there is a great deal of variation within ethnic groups when it comes to hair texture. For example, some individuals of African descent may have hair that is less tightly coiled and more manageable, while others may have extremely wiry hair that is difficult to style. Similarly, individuals of Asian descent may have hair that is more thick and coarse than the typical straight, fine hair that is associated with this ethnic group.

Hormones and Hair Texture

Hormones also play a role in determining hair texture, particularly during puberty and pregnancy. During these times, the body experiences significant hormonal changes that can impact the growth and texture of hair.

During puberty, the body produces higher levels of androgens, which are male hormones. These hormones can cause hair to become thicker and coarser, particularly in areas such as the pubic region and underarms. They can also cause the hair on the head to become more oily and prone to breakage.

Similarly, during pregnancy, the body experiences a surge in hormones, including estrogen and progesterone. These hormones can cause the hair to become thicker, shinier, and more voluminous. However, after pregnancy, when hormone levels return to normal, the hair may return to its previous texture or even experience postpartum hair loss.

Hormonal changes can also impact hair texture in individuals with certain medical conditions. For example, individuals with polycystic ovary syndrome (PCOS) may experience excessive hair growth in areas such as the face, chest, and back, due to increased levels of androgens.

Environmental Factors and Hair Texture

Environmental factors can also impact hair texture, particularly if the hair is exposed to harsh chemicals or excessive heat. For example, frequent use of hair straighteners, curling irons, or blow dryers can damage the hair and alter its texture over time. Chemical treatments such as perms or relaxers can also have a lasting impact on hair texture.

In addition, exposure to certain elements in the environment can also impact hair texture. For example, exposure to saltwater or chlorine can cause hair to become dry and brittle, while exposure to UV radiation can cause hair to become more porous and prone to breakage.

Hair Care Practices and Hair Texture

Finally, hair care practices can also impact hair texture. For example, individuals who frequently use harsh shampoos or conditioners may strip the hair of its natural oils, causing it to become dry and brittle. On the other hand, individuals who use moisturizing hair products and avoid heat styling may be able to maintain healthier, more manageable hair.

In addition, the way in which hair is brushed or styled can also impact its texture. For example, individuals who brush their hair vigorously or use tight hair ties may cause damage to the hair shaft, leading to frizziness and breakage. Gentle brushing and looser hairstyles, such as braids or buns, may be better for maintaining healthy hair texture.


In conclusion, hair texture is largely determined by genetics, ethnicity, hormones, environmental factors, and hair care practices. While some individuals may be born with thick, wiry hair, others may experience changes in hair texture over time due to environmental or hormonal factors. By understanding the factors that impact hair texture, individuals can make informed decisions about how to care for their hair and maintain healthy, manageable locks.

Why are some hairs thick and wiry?
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