A hairy business
Let your hair down: 10 amazing facts about human hair
Published on January 29, 2026
Image: Ali Pazani
The human body is incredible, from its mechanics to its ability to heal and adapt to multiple environments and situations. Hair, as part of our body, is no exception to this complexity and wonder. Let’s take a look at 10 amazing facts about our hair that you may not know!
Two things called ‘hair’
Image: Ian Talmacs
The word hair is used to describe two separate and distinct components: the follicle and the shaft. The follicle—what we commonly refer to as the root—is a living organ located in the dermis of the scalp. It’s responsible not only for growing hair but also for helping regenerate skin after a wound.
On the other hand, the shaft—often referred to as the strand—is a filament composed of layers of keratin, the same protein that makes up our nails. Unlike the follicle, the hair shaft is technically dead because it consists of dead cells.
The structure of a hair strand
Image: Joyful Bird
Each hair strand is composed of three layers. The innermost layer is the medulla, and even scientists are still uncertain about its exact function. Surrounding the medulla is the cortex, which absorbs water and provides strength to the strand. The cortex also contains melanin, the pigment that determines hair color, and its shape plays a major role in whether hair is straight or curly. The outermost layer is the cuticle, which serves primarily to protect the hair shaft.
Hair color and genetics
Image: Tyler McRobert
Hair color is primarily influenced by several genes, including MC1R, which plays a key role in melanin production. However, not everyone produces the same type or amount of melanin. Higher amounts of melanin result in black hair, while varying levels and types of melanin—along with genetic variations—produce brown, blond, and other shades.
Red hair, the rarest natural color, is caused by a mutation in the MC1R gene and is inherited in a recessive pattern. This means a person must inherit two copies of the mutated gene (one from each parent) to have red hair, though many people carry the gene without expressing the trait.
Hair growth
Image: William Warby
Growing at a rate of about 0.2 to 0.5 inches per month, hair is the second-fastest growing tissue in the human body—surpassed only by bone marrow. This rate is influenced by factors such as genetics and ethnic background. Other variables, such as age, lifestyle, or health, can also have an impact on our hair growth and density.
Hair shedding
Image: Sohan Rahat
We usually think of cats or dogs when it comes to shedding, but humans also shed hair regularly. After all, hair is a trait shared by all mammals. The average person sheds between 50 and 100 strands of hair per day, though this number can increase in response to stressors such as illness, hormonal changes, or emotional stress. Once the stress subsides and the body readjusts, the excess shedding typically stops.
Grey hair
Image: Joseph Chan
Commonly associated with aging, grey hair isn’t a color in itself but rather the result of a loss of pigment. As part of the natural aging process, melanin production in the hair follicle gradually decreases and eventually stops, causing strands to appear grey or white.
Genetics and ethnic background play a major role in determining when and how the greying process begins. Some people are even genetically predisposed to start greying at a very young age.
Hair texture
Image: Jaroslav Devia
Hair texture is commonly associated with ethnic background, but that’s not the only factor involved. Texture is primarily determined by genetics, and while genetics are closely tied to ancestry, all hair textures can be found across different populations.
Scientists believe that hair texture—specifically curl pattern and volume—is a result of the shape of the shaft. A round shaft typically produces straight hair, while flatter or more oval-shaped shafts tend to create curls and waves.
Water-repellent hair
Image: Amritanshu Sikdar
Depending on the structure of your hair cuticle, your hair may be more or less water-repellent. Hair shafts with a more porous cuticle absorb water easily but also lose moisture quickly. In contrast, shafts with a tighter-packed cuticle struggle to get wet and are slow to dry.
Resting hair
Image: Sonja Langford
Hair doesn’t grow continuously or all at once—each strand follows a cycle with distinct phases. First comes the growing phase, which varies depending on the type of hair (for example, facial hair grows faster and for a shorter period than scalp hair). Eventually, growth slows down, and the strand detaches from the root.
After this, the hair enters a resting phase, during which it remains in place until it is naturally shed. At any given time, we have hairs in all stages of this cycle, which is why we regularly shed hair without going bald.
Hair is a data bank
Image: Hans Reniers
Like any other part of the body, hair contains DNA and genetic material, which means a person can be genetically identified from a single strand, provided it includes the root. But hair holds even more information. The analysis of a hair strand can reveal substances that were present in a person’s bloodstream over time, including vitamins, minerals, medications, alcohol, and other substances.
