A hairy business

Let your hair down: 10 amazing facts about human hair

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!

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

From head to toe

This is what happens when you crack your knuckles! 10 human body myths

Image: BUDDHI Kumar SHRESTHA

Is it true that we only use 10% of our brains? Do carrots really improve your vision? Science has spoken and said, "Fake!" There are many widely believed myths about the human body, but despite their popularity and long history, it has been proven that most of these claims are actually not true. Join us as we uncover 10 myths about the human body that have been debunked!

Image: GMB Fitness

What do you usually do when you're nervous? Some people tap their feet, others fuss with their hair, and some crack their knuckles like a fireworks show on the 4th of July. If you belong to the last group, this info will help you.

There's a common myth that cracking your joints can cause you to develop arthritis. However, while most doctors advise against making a habit of this practice, there isn't enough scientific evidence to establish a direct link between the cracking (caused by gas bubbles forming and collapsing) and arthritis.

Image: Helen Barth

You've probably heard that shaving makes body hair grow thicker and darker. But this is a myth!

While it may seem like the hair grows back thicker, there's actually a simple explanation for this. The razor cuts the hair at the surface of the skin, leaving a blunt tip. As the hair grows back, that tip feels sharp to the touch, which is why we tend to believe that the hair has become thicker. In contrast, when you wax, every hair is removed from the root, so it grows back with a softer tip.

Image: Milad Fakurian

This is one of the most famous myths related to the human body. Although it's quite interesting, it's actually false that we only use a small percentage of our brains.

Neuroscience has shown that we use all of our brain, with distinct parts dedicated to different functions. In fact, various tests, such as MRI and PET scans, reveal that different areas of our brain are active even when we're asleep.

Image: David Travis

Carrots' high vitamin A content can help maintain eye health. However, this vegetable won't make you skip the eye doctor.

Perhaps this is bad news for Bugs Bunny, but the myth that eating carrots drastically improves vision has already been disproved. This idea is thought to have arisen during WWII when it was suggested that eating carrots helped British pilots see better at night. In reality, the pilots' improved vision was due to the use of radar, but the association between carrots and better vision stuck.

Image: Robina Weermeijer

There was a theory that the human body can't produce new neurons after a certain age. That's a bit scary, isn't it? Fortunately, neuroscience has once again put on its gloves to prove this is a myth.

It has been shown that our body is indeed capable of producing new neurons through a process called "neurogenesis." Although less frequent than in childhood, neurogenesis does occur in adulthood and is boosted by physical exercise and mental stimulation.

Image: Marvin Meyer

Remember that time when you accidentally swallowed gum, and an adult told you it would stay stuck in your stomach for years? Well, thankfully, that's just a myth!

Although your body can't digest gum like other foods, the natural movement of your digestive system helps it pass through and eventually be expelled.

Image: Mustafa Bashari

For years, egg yolks have been viewed with suspicion. Many believed they were bad for your heart or could significantly raise your blood cholesterol levels.

However, recent studies suggest that if you're not at risk or don't have specific cholesterol-related issues, there's no need to worry much about egg yolks.

Image: Raphaël Biscaldi

There's a well-known idea that swimming after eating is dangerous to your health and can cause cramps. Remember those moments of staring longingly at the pool, counting down the mandatory 30 minutes after eating? Thankfully, this wait is no longer necessary, as that idea has been discredited as a myth!

While you may feel a little heavy if you go swimming shortly after a meal, the truth is, under normal conditions, swimming with food in your stomach is generally considered safe.

Image: Harris Ananiadis

Often portrayed in movies, TV shows, and cartoons, there's this idea that waking a sleepwalker can have fatal consequences. But it turns out that there's no need to fear, as science has confirmed that as a myth.

However, while it's safe to (gently) wake a sleepwalker, it's generally better to simply guide them calmly back to bed instead.

Image: Oleg Ivanov

It has long been believed that a person's nails and hair continue to grow even after passing away. Although there are reasons to believe it, this creepy myth has been disproved.

What actually happens is that the skin dehydrates and retracts, creating the illusion that the nails or hair are longer. Both hair and nails require living cells and a blood supply to grow.