The primary purpose of curly hair, particularly tightly curled hair, is thermoregulation for the brain, acting as a natural sunshade to protect the scalp from intense solar radiation and minimize heat absorption, which allowed for the evolution of larger human brains by reducing the need for excessive sweating and water loss. It creates a barrier, keeping the head cool in hot climates, while straight hair might provide better insulation in cold climates, showing how different textures are suited for different environments.
The researchers found that all hair reduced solar radiation to the scalp, but tightly curled hair provided the best protection from the sun's radiative heat while minimizing the need to sweat to stay cool.
Tightly curled hair better protects the scalp from solar radiation, the new research shows, and it doesn't lie flat against the skin while wet—a boon in hot conditions that can make humans sweat, like those encountered by our hominin ancestors in Africa millions of years ago.
Gen Z loves curly hair because it embodies their focus on natural beauty, individuality, and self-expression, heavily influenced by social media trends and celebrities embracing their authentic textures, moving away from heavily styled looks to showcase unique curls, sometimes enhanced with modern, softer perms. This shift celebrates unique textures, rejecting past pressures to conform to straight hair standards, with styles like the curly-top fade becoming popular for men too.
Studies have shown that the morphology of the hair follicle can be influenced by a person's race. Individuals of African ancestry, for example, are more likely to have curly hair due to the oval shape of their hair follicles.
Men are naturally drawn to women with healthy, shiny hair, and curly hair is no exception. The texture of curly hair adds body and volume, creating a look that is hard to resist. Finally, men are attracted to curly hair because it is unique and eye-catching.
The rarest hair type is generally considered Type 1A, which is extremely fine, straight, and wispy, lacking any natural bends or waves, making it difficult to hold a curl but naturally sleek and prone to oiliness. While curly hair types (Type 3 & 4) are less common globally, 1A stands out as the least voluminous and textured straight hair, often seen in people of East Asian descent, though it's considered rare across all populations due to its unique fineness.
Type and texture
As the follicle shrinks with age, the shape can also slightly change. Damage due to environmental factors and chemicals may also affect follicles and their shapes. How silky or coarse your hair is can also change with age. Sometimes texture changes because of hair thinning.
Fine hair is the most fragile of the hair texture types as the individual strands of hair are very thin. This texture type may not hold style well and it will likely get oily easily. A common need for fine haired folks is more volume, but too much product will weigh the hair down and ultimately cause breakage.
Mechanical properties vary among different ethnicities. Asian hair demonstrates the highest hardness and elastic modulus, followed by Caucasian and African hairs, respectively.
The gene for curly hair in Caucasians
It has been long established that curly hair is a dominant trait in Caucasians and straight hair is recessive.
Our hair loss is thought to have happened well before modern humans migrated north of Africa. So body balding would also have allowed our ancestors to better control body temperature in hotter climes. You may need a coat sometimes, but at least you don't have to carry it around all year long.
Dry and frizzy hair –
Every person with curly hair faces the possible scenario of a dry scalp and dry hair. 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.
We confirm that scalp hair reduces heat gain from solar radiation and find an effect of hair morphology. Our results show that tightly curled hair provides the most effective protection for the scalp against solar radiation, while minimizing the need for sweat to offset heat gain.
Naturally, curly hair is relatively common but varies by population and ethnicity. Globally, it's estimated that about 11% of people have naturally curly hair. The prevalence can be higher or lower in specific regions due to genetic diversity and ancestral backgrounds.
“The twenties are often the best decade for hair,” Perrier says, adding that it's also when people like to experiment. Whether it's frequent coloring or the sometimes intensive use of hot tools, hair can become fragile. Here's how to take care of your hair in your 20s.
Stringy, straight ends and looser curl patterns. These sorts of noticeable changes in texture can be a red flag. Excessive heat is usually the culprit, but bleach/color damage, dryness or over-manipulation can be contributing factors as well.
The "Big 3" for hair regrowth typically refers to a combination of Minoxidil, Finasteride, and Ketoconazole shampoo, addressing hair loss through different mechanisms: Minoxidil stimulates follicles, Finasteride blocks DHT (the hormone causing shrinkage), and Ketoconazole reduces inflammation, with microneedling sometimes suggested as a fourth option.
In straight type, thin hair was judged most attractive, whereas in wavy type, hair with mean diameter received the highest attractiveness judgments. In conclusion, there was considerable variation in age, health and attractiveness perception of hair with regard to effects of hair diameter, type, and color.
Common nutritional deficiencies that can cause hair loss include iron, zinc and biotin deficiencies. Too much sugar can cause hair loss, so a low-sugar diet is recommended for healthy hair. Too many fatty foods can lead to hair loss, so cutting down on saturated fats can lead to healthier hair.
There's no single "ugliest" hair color, as beauty is subjective, but natural red hair is often cited as least popular in attractiveness studies due to rarity and stereotypes, while some find unnaturally dyed colors (like harsh yellow blonde from bleaching, flat coal black, or certain aggressive fashion shades) less appealing, or simply, a color that clashes with a person's skin tone.
If you have curly hair you are perceived as being courageous, outspoken, and spontaneous. You are probably someone who likes to challenge perceptions and norms. You celebrate your uniqueness and value your roots. Unkempt bouncy curls give you a playful vibe.
Curly hair cuts with bangs are making waves in 2025. From soft curtain bangs to full, curly fringe, this look adds character to any haircut. Bangs pair beautifully with long curls, bobs, or layered cuts, framing the face while keeping the overall style playful and chic.
Embracing Natural Texture
One of the key reasons for the popularity of curls among Gen Z is the emphasis on embracing and enhancing natural beauty.