62 Amazing Human Body Facts (Backed by Science)

By Karin Lehnardt, Senior Writer—Reviewed for accuracy by the FactRetriever editorial team

Published October 24, 2016Updated November 10, 2025

The human body is an extraordinarily complex biological system made up of bones, muscles, organs, cells, and networks that work together every moment of your life. Many of its most fascinating traits sound unbelievable at first, until science explains how they work. Below are carefully selected facts about the human body, organized by system and based on widely accepted scientific research. These facts focus on anatomy, biology, and physiology, avoiding myths, exaggerations, and speculation

Bones & Muscles: The Body's Built-In Engineering

Your Skeleton Weighs about 21 Pounds
An adult who weighs 150 pounds has a skeleton that weighs about 21 pounds._[1]
Bones: Stronger Than Steel . . . But Not Unbreakable
Bone is five times stronger than a steel bar of the same width. Just don't jump off a roof; bone is still brittle and can fracture on impact._[17]
A Quarter of Your Bones Are in Your Feet
In an adult human, 25% of their entire skeleton is in the feet. Each foot packs 26 bones, which is 52 total of the 206 bones in your body. These bones are an engineering feet that carries you, balances you, and still manages to let you dance!_[6]

Your skeleton: 206 bones, 21 pounds, stronger than steel (but brittle enough to break), and continually amazing

The Strongest Bone in the Human Body is the Femur
The femur can support 30 times the weight of a person's body. Ounce for ounce, that's stronger than steel._[14]
The Longest and Shortest Bones in the Human Body
The longest bone in an adult human is the thighbone (femur), measuring about 18 inches (46 cm). The shortest bone is in the ear and is just 0.1 inches (.25 cm) long, which is shorter than a grain of rice._[15]
Bones: Forever Young
A human skeleton renews itself completely every 10 years thanks to constant bone turnover._[15]
One Step, 200 Muscles in Motion
For an adult human, taking just one step uses up to 200 muscles, from your toes to your hips to your abs. Walking isn't a simple motion; it's a full-bodied orchestra._[17]
The Gluteus Maximus is the Body’s Largest Muscle
It is large and powerful because it has the important job of helping you stand, move, and generate power._[10]
The Mighty Masseter
The strongest muscle in the human body is the masseter, or the jaw muscle. It can bite down with up to 200 pounds of force._[6]
Your Fingers are "Remote Controlled"
Fingers don’t have muscles that facilitate movement. The tendons in our fingers are moved by the muscles of the forearm. It's like remote controlled tools built into your hands!_[5]
Brain & Nervous System: Your Inner Supercomputer

Your Brain Fits in a Pillowcase
If you spread out an adult human’s brain, it would be about the size of a pillowcase._[10]
Brain Messages Travel at Lightning Speed
Messages from the human brain travel along nerves at up to 200 miles an hour (322 km/h), which is faster than a race car. However, some messages, like pain, travel slower, at a few miles per hour._[14]
Counting Your Brain Cells Would Take Millenia
With over 86 billon neurons, it would take almost 3,000 years to count them (even at one neuron per second). Your brain is truly a universe of its own!_[17]
Your Brain: A 10-Watt Powerhouse
Even though the human brain is just 3 pounds, it uses just as much power as a 10-watt light bulb and runs your entire reality._[15]
Heart & Circulation: Nature's Engine that Never Rests

Your Heart Beats Over 3 Billion Times
A human heart beats over 3 billion times during an average human lifespan._[1][17]
Your Blood Travels about 12,000 Miles . . . In One Day
In an adult human, blood circulates about 12,000 miles (19,000 km) a day. This is like traveling from California to China and back._[17]
Digestion & Organs: The Chemistry Lab Inside You

You Have About as many Bacterial Cells in Your Body as Human Cells
Most bacteria live in your gut and help with immunity and digestion._[11]
Your Stomach: A Super Stretchy Container
An adult’s stomach can hold over two quarts (1.9 l) of food. That’s enough to fill four large or eight small drinking glasses._[17]

A person will eat approximately 35 tons of food in a lifetime

You'll Eat 35 Tons of Food in Your Life
In a lifetime, a human body will process about 100,000 pounds of food._[17]
Your Liver Has Wolverine Superpower
The liver the largest internal organ and is the only organ that can regenerate itself. Even if up to 75% of it is removed, it can grow back to full size. However, repeated damage to the liver can eventually injure and scar this amazing organ._[10]
Your Gut: A 5-Pound Bacteria Factory
The average person has about 5 pounds of bacteria in his or her digestive system._[15]
Your Intestines Are As Long As a Minivan
An adult small intestine is about 22-23 feet long, which is longer than a minivan. It is were most nutrient absorption happens._[1]
You'll Drink Over 12,000 Gallons Of Water In Your Lifetime.
By the time a person reaches 70 years old, he or she will have consumed over 12,000 gallons of water, enough to fill a small swimming pool._[17]
Anyone For Some Borborygmi?
Borborygmi is the noise that your stomach makes when you are hungry._[2]
Two Swimming Pools of Saliva
The average human produces 25,000 quarts of saliva in a lifetime, enough to fill two swimming pools._[14]

Your spit contains your entire genetic blueprint

Daily Output: 3-8 Ounces of Feces
The average human produces about three to eight ounces of feces a day. Your digestive system works hard to keep things movings!_[17]
Five Years of Life Spent Eating
Humans spend about five years of their lives eating. That's a lot of snacks, meals, and bites. Every forkful adds up!_[15]
Senses: Your High-Resolution Way of Experiencing the World

Taste Happens Faster Than A Blink
The tongue can detect taste in .0015 seconds, which is faster than the blink of an eye._[17]

The taste cells in our taste buds live for only about two weeks

Taste Buds are not Visible to the Naked Eye
The little bumps that can be seen on the tongue are actually papillae, on top of which rest the taste buds. You have over 10,000 taste buds that detect sweet, sour, salty, bitter, and umami._[17]
Your Eyes See 10 Million Colors
A human eye can distinguish between approximately 10 million different colors._[17]
Green is Your Superpower Color
Humans can see more shades of green than any other color. This likely evolved because our ancestors needed to detect subtle variations in plants and foliage._[7]

A disorder of the inner ear causes every sound within the body to be amplified, including eye movements

Some People Can Hear Their Own Eyeballs
Some people can hear their eyeballs moving around in their head._[4]
Hearing Colors
People with chromesthesia "see" color in sounds. Musicians with chromesthesia include Vincent van Gogh, Franz Liszt, Billy Joel, and Pharrell Williams._[3]
Anosmia: When You Can't Smell
A person suffering from anosmia is unable to detect smells._[1]
Skin, Hair,& Nails: You Body's High-Tech Protective System

Your Amazing Fingerprints
No matter how badly fingerprints are damaged, they will always grow back in their original pattern._[10]
Some Surprising Parts of Your Body Share The Same Type Of Cells
The same skin cells that make up a human vagina are the same type of cells that are in a human mouth. They are the non-keratinized squamous epithelium, which are built to stay moist and handle a lot of movement._[17]
A Human’s Ears and Nose Never Stop Changing Shape
Cartilage slowly sags over time, which makes them look longer. They are not actually growing new tissue; gravity and aging remodel them._[17]
Your Skin Gets a Monthly Makeover
You get a new top layer of skin (epidermis) every 30 days. It's a monthly refresh for your body's largest organ._[1]
Thickest and Thinnest Skin
Your skin is its thickest on your feet (1.4mm) and thinnest on your eyelids (0.2mm)._[12]
Billions of Tons of Human Dust in the Atmosphere
Dead skin comprises about a billion tons of dust in the earth’s atmosphere. Talk about a carbon footprint._[12]
Fingernails vs. Toenails: The Speed Race
Fingernails grow about 3 millimeters per month, which is about twice as fast as toenails._[1]
Your Skin: A Tent-Sized Super Organ
An adult’s skin weighs between 8 and 11 pounds (3.6 to 5 kg). It’s surface area is about 18-22 square feet (1.7 to 2 sq. m), which is the size of the floor in a one-person tent. Your skin protects, senses, and keeps your body running smoothly._[17]
Eyebrow Stats
The average person has about 250 hairs per eyebrow. Eyebrow hairs have a lifespan of about 4 months._[8]
Lungs: Light But Mighty
The word “lung” is from a German word meaning “light”; together two adult human lungs weigh only 2.5 pounds (1.1kg)._[17]
A Fancy Name for Earwax
The medical name for ear wax is "cerumen."_[1]
The Smooth Spot Between Your Eyebrows
The space between the eyebrows is called the "glabella," which is derived from the Latin word glabellus, meaning smooth._[9]
Uvula: Your Tiny Grape Helper
The uvula is the fleshy extension that hangs down from the back of the soft palate. It is from the Latin word, uva, meaning "grape."It helps with speech, swallowing, and triggering your gag reflex._[1]
Fun & Weird Human Body Facts

Fat=Soap Potential
You have enough body fat to make seven bars of soap._[16]
A Universe of Bacteria
There are more bacteria in a human mouth than there are people in the world. Billions of bacteria live on your tongue, teeth, and gums. Luckily, most are harmless and can even protect you!_[17]

It would take a someone typing 60 words per minute, eight hours a day, around 50 years to type the human genome

Your DNA Could Stretch From Earth to Pluto and Back
If a human being’s DNA were uncoiled, it would stretch from Earth to Pluto and back, which is about 10 billion miles. You're essentially a cosmic blueprint._[17]
Your Body Starts To Digest Itself After Death
Within three days of dying, the enzymes that digested a person’s food will begin to digest that person’s body. It's called autolysis._[17]
The Human Body's Giant Cell: The Egg
The largest cell in the human body is an egg (or ovum) and is barely visible to the naked eye. Tiny but mighty._[6]
Your Amazing Knees
For every pound you weigh, your knees receive four times the amount of stress._[10]
The Rare Forked Uvula
Two percent of the human population has a bifid uvula, which means the little flap in the back of the throat has a forked appearance. It's a harmless but surprisingly rare twist of anatomy._[1]
Sperm: Tiny Swimmers in Billions
Semen normally contains 1-8 billion sperm per fluid ounces (140-300 million sperm per millimeter), each one racing to the egg. Talk about a miniature marathon._[6]
Lifetime Walker: Around the World Four Times
An average person walks about 100,000 miles (160,934 km) in his or her lifetimes, which is like walking around the world four times at the equator._[17]

An adult is made up of 7,000,000,000,000,000,000,000,000,000 (7 octillion) atoms

You're Made of 7 Octillion Atoms
An adult human body is made up of about 7 octillion atoms. That's more atoms than stars in the observable universe._[10]
Sleep: Humans vs. python vs. dog
Adult humans spend about 33% of their lives asleep. A python spends about 75% of their life, and a dog spends about 44%._[17]
Turning A Weakness Into A Superpower
Matthias Schlitte (b. 1987) was born with a rare bone disorder that made his right arm bigger than his left. Rather than seeing this as a weakness, he became a professional arm wrestler._[1]
Take a Deep Breath
The average person breathes about 20,000 times a day._[1]
Intergluteal Cleft: A Fancy Name for Your Bum Crack
The medical term for "bum crack" is the intergluteal cleft_[13]

Amazing Human Body Facts INFOGRAPHIC

Don't forget to share with someone whose brain you'd like to amaze!
*For informational purposes only_[1]

References

¹ Bennet, Howard, Dr. The Fantastic Body: What Makes You Tick and How You Get Sick. Emmaus, PA: Rodale Books.

² "Borborygmus." Online Etymology Dictionary. Accessed: January 20, 2019.

³ "Famous People with Synesthesia." PSU. November 2, 2021. Accessed: January 29, 2025.

⁴ Greenemeir, Larry. "Medical Mystery: How Can Some People Hear Their Own Eyeballs Move?" Scientific America. September 1, 2011. Accessed: August 20, 2016.

⁵ "How Do Fingers Work If They Don’t Contain Muscles?" ABC Science. Accessed: November 28, 2017.

⁶ How The Body Works. New York, NY : DK, 2016.

⁷ Jimison, Robert. "Why We All Need Green in Our Lives." CNN. June 5, 2017. Accessed: October 6, 2022.

⁸ Johnson, Allie. "Why Do People Have Eyebrows?" AllAboutVision. April 11, 2022. Accessed: January 29, 2025.

⁹ New Sydenham Society, Henry Power, Leonard William Sedgwick. The New Sydenham Society's Lexicon of Medicine and the Allied Sciences: (Based on Mayne's Lexicon). 1888.

¹⁰ Roberts, Alice. The Complete Human Body : The Definitive Visual Guide. New York, NY : DK Publishing, 2016.

¹¹ Saey, Tina Hesman. "Body's Bacteria Don't Outnumber Human Cells That Much After All." Science News. January 8, 2016. Accessed: November 23, 2025.

¹² "Skin." Cleveland Clinic. Accessed: January 30, 2025.

¹³ "The Medical Term for Butt Crack." Medical Word Meanings. Accessed: August 9, 2017.

¹⁴ Ultimate Weird but True: 2. National Geographic Kids. Washington D.C.: National Geographic Society.

¹⁵ Walker, Richard. Human Body. London : DK, 2014.

¹⁶ "Wednesday Wisdom." SomaTechnology. Accessed: November 10, 2025.

¹⁷ Wilsdon, Christina. Ultimate Body-pedia : An Amazing Inside-out Tour of the Human Body. Washington, D.C. : National Geographic Society, 2014.

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