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.

Secret uses

There’s a hidden microphone in your phone, and here’s where it is

You’ve probably twisted a bread bag closed, filled up your car, or pulled a sheet of aluminum foil from the box thousands of times without giving it a second thought. But many of the everyday objects we’ve used for decades have clever features that most people never notice. From the tiny pocket on blue jeans to the little arrow next to your gas gauge, these hidden designs have practical stories behind them, and once you know them, you’ll never look at these familiar items the same way again.

If you own an iPhone, you’ve probably noticed the tiny black dot next to the rear camera. It’s small, so people tend to assume it’s another camera sensor or even part of the phone’s design. The small hole found near the camera bump on every iPhone is actually a rear microphone.

It captures clearer audio when you’re recording videos and helps reduce background noise during FaceTime and regular phone calls. If you own an iPhone Pro model from the iPhone 12 Pro onward, you'll also see a larger dark circle. That’s the LiDAR scanner, which sends out invisible infrared light to create a 3D map of your surroundings. It helps the camera focus faster in low light, powers Apple’s Measure app, and makes augmented reality features much more accurate.

Whether it's a holiday dinner, an anniversary, or simply a nice meal with friends, you’ve probably held a wine bottle and noticed the deep indentation in the bottom. Many people tend to think the deeper the indent, the fancier the bottle.

That indentation is called a punt, and it’s been a part of the bottle-making for centuries. Originally, it helped strengthen hand-blown glass bottles, making them less likely to crack under pressure. Today, it still adds structural stability, particularly for sparkling wines, while also giving servers a comfortable place to rest their thumb when pouring, though some say it helps collect the sediment as wines age. In any case, a deeper pun doesn’t automatically mean a better or more expensive bottle.

Almost every driver has experienced that awkward moment at the gas station. You pull up to the pump, step out of the car, and suddenly realize the fuel door is on the opposite side.

To help prevent exactly that situation, many modern vehicles include a small arrow next to the gas pump symbol on the dashboard’s fuel gauge. The arrow points towards the side of the vehicle where the fuel filler door is located. It’s a small detail on the dashboard, yet once you notice it, you’ll never have to circle the pump again.

All elevators look pretty much the same. Bigger or smaller, they all look similar, a gray box with a mirror and buttons. But if you pay close attention, you may notice there’s a small round opening near the top of the door.

That opening is a keyhole used by trained maintenance technicians and emergency responders. With a special elevator key, they can manually unlock the landing doors when repairs are needed or if passengers become trapped inside. The system allows professionals to reach the elevator safely without damaging the doors or relying solely on electrical controls. Hopefully, most of us will never need to see it in action. But in an emergency, that tiny opening becomes one of the most important parts of the system.

If you’ve ever stood in the bread aisle comparing loaves, you’ve probably noticed the colorful plastic clips or twist ties holding the bags shut. Contrary to what many think, they’re not simply a part of the packaging.

For many bakeries and grocery stores, the colors indicate the day a loaf was delivered or baked. While the exact color schedule can vary between bakeries and regions, employees use the system to quickly spot older inventory and rotate fresher bread to the back of the shelf. That way, customers are more likely to pick up the freshest loaf available.

Whether you wear jeans every day or only pull them out for yard work, you’ve probably noticed the tiny extra pocket tucked inside one of the front pockets. It’s too small for a phone and not very useful for loose change, but there’s a reason for it.

Back in the 1800s, when Levi Strauss & Co. created rugged denim pants for miners, ranchers, and cowboys working across the American West, pocket watches were commonplace. Workers needed a safe place to carry their watches while riding horses, so that little pocket was designed specifically to protect the watch from damage. Pocket watches disappeared, but the tiny pocket became such an iconic part of blue jeans that manufacturers have continued including it for well over a century.

Almost everyone has had the same frustrating experience. You pull on a sheet of aluminum foil, and suddenly the entire roll slides out of the box and lands on the kitchen counter.

That’s exactly why major manufacturers such as Reynolds introduced the small side tabs, known as end locks, in the mid-1990s. By pressing the tabs inward, they hold the cardboard roll in place like built-in axles. This keeps the roll from sliding out of the box, makes it much more stable as you pull, and helps the serrated edge cut a cleaner, straighter sheet. It also reduces waste by preventing the foil from bunching up or tearing unevenly. It’s a simple design, yet useful as it can get.

Every household has pens lying around for all kinds of purposes. And most of them have a common feature, a hole in the cap, which isn’t simply part of the design.

BIC and other pen manufacturers included the opening as a safety feature. If someone, especially a child, accidentally swallows a pen cap, the hole can allow a small amount of air to pass through, reducing the risk of complete airway blockage while emergency help is on the way. The design became part of border efforts to improve consumer product safety after choking incidents drew attention to the danger of small plastic objects.

If you grew up sewing or watching somebody do it, you probably remember the classic tomato-shaped pincushion sitting beside the sewing basket. Hanging from it was a tiny red strawberry that looked like nothing more than a cute finishing touch.

In reality, that little strawberry has its own job. Instead of soft stuffing, it’s filled with emery, a gritty material made from crushed abrasive minerals. Running pins and needles through it helps polish away tiny spots of rust, smooth rough edges, and keep the points sharp enough to glide through fabric more easily.

Think back to the first time you learned to type. Maybe it was at work, or on a family computer. Wherever it was, someone probably told you to keep your fingers on the "home row." That’s exactly why the F and J keys have tiny raised ridges.

The bumps let your index fingers find the correct starting position by touch alone, allowing you to type without constantly looking down at the keyboard. The technique, known as "touch typing," is widely credited to American court stenographer Frank Edward McGurrin, who demonstrated it in 1888. As typewriters became more common, manufacturers experimented with different ways to help typists orient their hands, and by the mid-20th century, companies such as IBM standardized the subtly raised plastic bars that remain on nearly every keyboard today.