What Are Tears Made Of and Why Do They Happen? 17 Facts (2023)

You’ve probably tasted your own tears and figured they have salt in them. What you might not realize is that tears contain a lot more than just that — and that they serve some very diverse purposes!

Let’s take a look at what tears are, how they work, and some surprising facts.

Your tears have a similar structure to saliva. They’re mostly made of water, but also contain salt, fatty oils, and over 1,500 different proteins.

Electrolytes in tears include:

  • sodium, which gives tears their characteristic salty taste
  • bicarbonate
  • chloride
  • potassium

Tears also contain lower levels of magnesium and calcium.

Together, these things make up three distinct layers in your tears:

  • The mucous layer keeps the tear attached to the eye.
  • The aqueous layer — the thickest layer — hydrates your eye, keeps bacteria away, and protects your cornea.
  • The oily layer prevents the other layers from evaporating and also keeps the tear’s surface smooth so that you can see through it.

You have three different types of tears:

  • Basal tears. These are always in your eyes to protect from debris and keep them lubricated and nourished.
  • Reflex tears. These form when your eyes are exposed to irritants, such as smoke and onion fumes.
  • Emotional tears. These are produced when you’re sad, happy, or feeling other intense emotions.

Dry eye syndrome is a common condition that happens when an inadequate quantity or quality of tears fails to lubricate your eyes properly. Dry eye syndrome can cause your eyes to burn, sting, or feel scratchy.

It may seem odd, but dry eyes also often cause watery eyes. The watering is a response to the irritation.

Some causes of dry eye are certain medical conditions, dry air or wind, and staring at a computer screen for prolonged periods.

(Video) Why Do We Cry?

According to the American Academy of Ophthalmology (AAO), you make 15 to 30 gallons of tears every year.

Your tears are produced by lacrimal glands located above your eyes. Tears spread across the surface of the eye when you blink. They then drain into small holes in the corners of your upper and lower lids before traveling through small channels and down your tear ducts to your nose.

While tear production can slow down due to certain factors, such as health and aging, you don’t actually run out of tears.

You produce fewer basal tears as you get older, which is why dry eyes are more common in older adults. This is especially true for women after menopause due to hormonal changes.

Syn-propanethial-S-oxide is the gas that causes you to tear up when you chop onions. The chemical process that creates the gas is a bit complicated, but also really interesting.

Let’s break it down:

  1. Sulfur in the ground where the onions grow mixes with the onion to create amino sulfides, which turn into a gas that protects growing onions from critters looking for a snack.
  2. The gas mixes with onion enzymes that are released when an onion is chopped, creating sulfenic acid.
  3. Sulfenic acid reacts with the onion enzymes and creates syn-propanethial-S-oxide, which irritates your eyes.
  4. Your eyes produce tears as protection against irritants.

That’s how and why chopping onions makes you cry.

7. It’s not only onions that can cause reflex tears

(Video) Why Emotional Tears Are Different

Anything that causes eye irritation can cause your lacrimal glands to produce tears. Some people are more sensitive to irritants than others.

Along with onions, your eyes might also tear up from:

  • strong odors, such as perfumes
  • bright lights
  • vomit
  • dust
  • chemicals, such as chlorine and cleaning products
  • too much screen time
  • reading small print or reading for prolonged periods

Your eyes and nasal passages are connected. When your lacrimal glands produce tears, they drain downward through your tear ducts, which are also called nasolacrimal ducts. This causes your tears to run down through the nasal bone and into the back of your nose and down your throat.

When you cry, producing many tears, the tears mix with the mucus in your nose, which is why your nose runs when you cry.

The purpose of emotional tears is still being researched, but is believed to be influenced by biological, social, and psychological factors.

Some researchers believe that crying is a social signal to get help from others when you’re in pain, sad, or feeling any type of distress or extreme emotion. Often, when you cry, it prompts others to offer support, which makes you feel better.

There is evidence that emotional tears contain additional proteins and hormones that aren’t found in the two other types of tears. These may have relaxing or pain-relieving effects that help regulate the body and help it return to its normal state.

Even if the jury is still out on the purpose of emotional tears, the benefits of crying are well documented.

Crying sends some visual signals. When you see someone cry, it’s a sign that they’re feeling sad or distressed. A 2011 study found that the tears we cry also send signals that others can smell even though tears are actually odorless.

The study used both saline and tears collected from women while they watched a sad movie. The male participants couldn’t smell the difference between the real tears and the saline. But those who sniffed the tears rated female faces less sexually attractive and reported lower sexual excitement, which was confirmed by testing saliva levels and using MRI.

(Video) Only 2000-2013 Kids Will Understand. Prepare To Cry 😭

Interestingly, a 2012 study looked at men’s testosterone levels in response to simulated baby tears. Men who had an effective nurturing response to the cries experienced a drop in testosterone. Those who didn’t experienced a rise.

While both of these studies describe effects that aren’t completely understood, the fact remains — tears send messages to others.

The term “crocodile tears” is used to describe someone who is pretending to cry. It came from the myth that crocodiles cry when eating humans, which was coined from the book “The Voyage and Travel of Sir John Mandeville,” published in 1400.

According to a 2007 study, crocodiles may actually cry when they eat. Alligators and caimans — which are closely related to crocodiles — were observed instead of crocodiles. When fed, the animals did shed tears, though the reason for the tears isn’t fully understood.

Newborns don’t produce tears when they cry because their lacrimal glands aren’t fully developed. They may cry without tears for the first month or so of life.

Some babies are born with or develop blocked tear ducts. In these cases, the baby can produce tears but one or both ducts may not be fully open or may be blocked.

Though it happens more often in babies and children, people of all ages can cry in their sleep.

Things that can cause sleep-crying or waking up crying include:

  • nightmares
  • night terrors
  • grief
  • depression
  • stress and anxiety
  • chronic pain
  • allergies

Animals produce tears to lubricate and protect the eye. While they may shed tears in response to irritants and injury, they don’t produce emotional tears like humans do.

There are many claims — a number of them backed by research — that women cry more than men. However, the gap seems to differ depending on part of the world, perhaps due to cultural norms.

No one knows exactly why women may cry more than men. It may have something to do with men having smaller tear ducts and emotional tears containing prolactin, which is a hormone that promotes breast milk production. Women have 60 percent more prolactin than men.

Pseudobulbar affect (PBA) is a condition that can cause uncontrollable tears. It’s characterized by episodes of sudden uncontrollable crying or laughing. The laughing usually turns to tears.

PBA usually affects people with certain neurological conditions or injuries that alter the way the brain controls emotion. Examples of these are stroke, Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis (MS).

Tears keep the surface of your eyes smooth and clear while also protecting against infection. Without enough tears, your eyes are at risk of:

  • injuries, such as corneal abrasion
  • eye infection
  • corneal ulcer
  • vision disturbances

The takeaway

(Video) The BANNED Teletubbies Episode That Made Kids Cry

Your tears work hard to protect your eyes, clear out irritants, soothe emotions, and even send messages to those around you.

While there are many reasons why we cry, tears are a sign of health and in some ways — at least in terms of emotional tears — uniquely human.


What are tears made from? ›

Our tears are made up of three components: lipid (oil), water and mucus. Each of these layers serves their own purpose. The oily layer is the outside of the tear film. It smooths the tear surface and keeps your tears from drying up too quickly.

What are the 3 types of tears? ›

We have three distinct types of tears: basal tears, reflex tears and emotional tears. Most researchers believe that emotional tears—triggered by strong feelings such as joy and sadness—are unique to humans.

What are the 4 functions of tears? ›

Tears keep your eyes wet and smooth, and help focus light so you can see clearly. They also protect your eyes from infections and irritating things, like dirt and dust. Every time you blink, a thin layer of tears called a “tear film” spreads across the surface of your cornea (the clear outer layer of the eye).

Why do tears come? ›

These arise from strong emotions. Empathy, compassion, physical pain, attachment pain, and moral and sentimental emotions can trigger these tears. They communicate your emotions to others. Emotional tears make you feel more vulnerable, which could improve your relationships.

Why do humans have tears? ›

We cry to protect our eyes, to wash out irritants and because, well, we are moved to tears. “There are three types of tears: basal tears, emotional tears and reflex tears,” explains David Silverstone, M.D., a professor of ophthalmology at the Yale School of Medicine.

Can tears clean eyes? ›

Actually, your tears clean your eyes every time you blink. Tears also keep your eyes moist, which is important for your vision. Tear glands produce tears, and tear ducts carry the tears from the glands to the surface of your eye.

Can human tears freeze? ›

First, the good news. Our eyes have natural protective mechanisms against cold and wind. Body temperature helps keep the eyes warm, and because of their salinity, tears freeze at a lower temperature than water to act as a kind of ocular antifreeze. Eyelids and lashes also help protect the eye.

Do your tears have DNA? ›

DNA was successfully extracted from fresh and aged tears stains. Tears stains containing low volumes also gave useful DNA profiles.

What color are human tears? ›

Tears are a clear liquid secreted by the lacrimal glands (tear gland) found in the eyes of all land mammals.

Can you run out of tears? ›

Cry all you want — you won't run out of tears

According to the American Academy of Ophthalmology (AAO), you make 15 to 30 gallons of tears every year. Your tears are produced by lacrimal glands located above your eyes. Tears spread across the surface of the eye when you blink.

Why do we cry when we get hurt? ›

Pain severe enough to make you cry does offer one benefit, though. Research suggests that when you cry, your body releases endorphins and oxytocin. These natural chemical messengers help relieve emotional distress along with physical pain. In other words, crying is a self-soothing behavior.

What are the 6 functions of tear film? ›

Findings from these studies show tears function to maintain comfort, prevent infection, suppress inflammation, heal traumatic and surgical injuries, clear debris and maintain high quality vision.

What are the two types of tears? ›

Take a look below at the three types of tears your eyes produce.
  • Basal Tears. Containing three separate layers, basal tears are complex. ...
  • Emotional Tears. Your eyes produce emotional tears when you're overcome with emotion. ...
  • Reflex Tears. The eye's lacrimal gland produces reflex tears, which are composed primarily of water.
Oct 5, 2022

What does human tears contain? ›

Tears are drops of liquid produced by the lacrimal, accessory lacrimal, and Meibomian glands, which contain proteins, enzymes, lipids, metabolites, electrolytes, and traces of drugs (9).

Why do tears bleed? ›

What causes tears of blood? Bloody tears can be the symptom of a number of conditions, including hormone changes, injuries and trauma, nosebleeds, high blood pressure, tumors, and blood diseases like hemophilia. In some cases, however, there is no root cause.

Why are tears so wet? ›

Glands under the skin of your upper eyelids produce tears, which contain water and salt. When you blink, tears spread and keep your eyes moist. Other glands produce oils that keep tears from evaporating too fast or from spilling out of your eyes.

Can tears turn to blood? ›

Crying bloody tears may seem like a fictional occurrence, but tears tinged with blood are an actual medical condition. Referred to as haemolacria, crying bloody tears is a rare condition that causes a person to produce tears tinged with, or partially made of, blood.

Can people cry without tears? ›

Clearly, people can cry without tears and be sad or remorseful without crying. The question is whether we can tell whether people are faking sadness and crying. Research has demonstrated people can somewhat differentiate between fake and genuine emotion, including crying and tears.

Why do I cry when I get mad? ›

When you get mad, your body produces a flood of hormones that stimulate strong reactions in your body — everything from a racing heart to sweaty palms to short-term memory loss. In response to the elevated stress level, you may cry.

Why do we cry when laughing? ›

High Emotional Situations and the Brain

Some believe crying while laughing occurs because both reactions are a result of increased emotion. By crying, the body attempts to return to a regular level of functioning. Some evidence suggests the same part of the brain controls both crying and laughing.

Can you smell tears? ›

After collecting the tears from several volunteers, Gelstein confirmed that they had no obvious smell. Men couldn't tell the difference between them and drop of saline that had been trickled down the cheeks of the same women.

Why are tears salty? ›

If you've ever tasted your tears, you may have noticed how salty they are. Tears are salty because they are made from water from our body that contains electrolytes (salt ions).

Do tears have poison? ›

Are tears toxic then? No! They actually remove toxins from our body that build up courtesy of stress. They are like a natural therapy or massage session, but they cost a lot less!

Is it OK to hold back tears? ›

In the short term, it can cause pesky problems such as irritability, anxiety, and poor sleep. But over time, repressing your tears can lead to cardiovascular diseases such as hypertension — or even cancer.

At what age do tears start? ›

At about two weeks old, newborns make just enough tears to keep their eyes moist. They don't produce real tears that you can see when they cry. Infants often don't develop real tears that you can see until they are about two months old.

Can a person have no tears? ›

Common causes of decreased tear production include: Aging. Certain medical conditions including Sjogren's syndrome, allergic eye disease, rheumatoid arthritis, lupus, scleroderma, graft vs. host disease, sarcoidosis, thyroid disorders or vitamin A deficiency.

What happens when we cry? ›

Researchers have established that crying releases oxytocin and endogenous opioids, also known as endorphins. These feel-good chemicals help ease both physical and emotional pain.

Why am I so tired after crying? ›

When someone cries, their heart rate increases and their breathing slows down. The more vigorous the crying, the greater the hyperventilation, which reduces the amount of oxygen the brain receives — leading to an overall state of drowsiness.

Why do I cry when I yawn? ›

You've probably noticed that your facial muscles contract when you yawn, including the area around your eyes. This puts pressure on tear-producing glands and, before you know it, your eyes fill with tears. If you're prone to watery eyes in the first place, you may be more likely to tear up when you yawn.

Are tears good for your skin? ›

Crying causes a release of endorphins or feel-good hormones and a reduction in stress hormones like cortisol, which have been linked to breakouts and other skin conditions. Though this may require more research, indications are that occasional bouts of crying can be good for the skin in the long run.

Is it better to cry or hold it in? ›

Chan, however, says that if you feel emotional and want to cry, it is best to let it all out rather than holding it back. “Crying can be helpful in some situations, but remember that it's only a means for you to express your feelings, be it anger, sadness, anxiety, frustration or grief,” he says.

Is it normal to not cry for years? ›

Some people cry more easily than others, and that's normal. People are different, so it stands to reason that emotional expression varies from person to person. If you can't cry at all, you might have a hard time working through your own emotions, and you could also find it tough to connect with others.

Why can't I breathe when I cry? ›

When you experience intense emotions and let your body release it (by crying) you might experience shortness of breath and rapid breathing. This happens because when you are stressed, the airways between the nose and the lungs become tight.

Why do I cry when I remember someone? ›

Dubbed "emotional contagion," it occurs when you're interacting with someone who is feeling something strong that in turn causes you to take on that same emotion, says social psychologist Daniel Rempala, PhD.

Why some people can t cry? ›

The inability to cry can have numerous possible causes. Antidepressants, depression, trauma, personality factors, social stigma, and certain medical conditions can all inhibit us from tearing up. Fortunately, many of the reasons we can't cry can be successfully treated and reversed.

How do you not cry when mad? ›

You can stop crying while you are angry by using both mental and physical approaches. Talking about your anger, thinking about positive events, and reflecting on your anger can help curb the tears. You can also remove yourself from the situation or engage in exercise to help you stop crying.

How do tear drops work? ›

Besides lubricating your eyes, some artificial tears also promote healing of the eyes and others work to decrease tear evaporation. Artificial tears may also contain thickening agents, which keep the solution on the surface of your eyes longer.

How many types of tear patterns are there? ›

The four most common tear patterns are crescent, L-shaped, U-shaped and massive tears. We have also noted some less common and atypical complex tear patterns which include tongue type tears and intra-substance mid-tendon tears.

Why are tear drops used? ›

This medication is used to relieve dry, irritated eyes. Common causes for dry eyes include wind, sun, heating/air conditioning, computer use/reading, and certain medications.

Why do my tears dry white? ›

Stringy, white mucus is often a result of allergic conjunctivitis. This allergic reaction may create deposits and material that clump together, settling inside of your eye or under your lower eyelid. People with allergic conjunctivitis may have to pull white, stringy mucus out of their eyes.

Why do I cry so much? ›

Crying easily can be a symptom of depression, anxiety, or a lot of stress in your life. Since HSPs feel so deeply and can experience sensory overload, we're more susceptible to strong feelings of depression or anxiety. We might feel alone in our sensitivity or isolate ourselves to reduce excess stimuli.

Do tears clean your face? ›

“Typically, tears are made from water, toxins, lysozyme, salt, lipids, and more,” she says. “Lysozyme, in particular, is an enzyme that helps get rid of bacteria, and, theoretically, it can combat against acne and other bacteria found on the face. Also, the salt content from tears can dry out the skin as well.”

Where do tears drain? ›

Tears drain into openings (puncta) on the inside corners of your upper and lower eyelids. The puncta lead to small canals (canaliculi) that move tears to a sac to a reservoir on the side of the nose (lacrimal sac). From there tears travel down a duct (the nasolacrimal duct) and drain into your nose.

Are human tears just water? ›

Your tears are mostly composed of water

Your tears have a similar structure to saliva. They're mostly made of water, but also contain salt, fatty oils, and over 1,500 different proteins. Electrolytes in tears include: sodium, which gives tears their characteristic salty taste.

Why do we get tears when sad? ›

Research suggests that when you cry, your body releases endorphins and oxytocin. These natural chemical messengers help relieve emotional distress along with physical pain. In other words, crying is a self-soothing behavior.

Why do you get tired after crying? ›

When someone cries, their heart rate increases and their breathing slows down. The more vigorous the crying, the greater the hyperventilation, which reduces the amount of oxygen the brain receives — leading to an overall state of drowsiness.

Can you smell your tears? ›

After collecting the tears from several volunteers, Gelstein confirmed that they had no obvious smell. Men couldn't tell the difference between them and drop of saline that had been trickled down the cheeks of the same women.

Can you cry underwater? ›

No thats not possible, though its obvious to think that tear ducts should work really fine under water. Density of water is more than that of air. When you are under water that fluide pressure wont let tear to come out.

Why are tears sticky? ›

If the source of dry eye disease is eye oil glands that aren't working properly — rather than insufficient tears — treatment is different. When these glands don't produce the right amount or consistency of oil, tears can become thick and sticky.

Is it healthy to sleep after crying? ›

Your stress level lowers when you cry, which can help you sleep better and strengthen your immune system.

Why do I feel dizzy after crying? ›

Emotions and thoughts

When you feel particularly stressed, anxious, angry or fearful, you may be more likely to experience dizziness. This is because some of your body's automatic reflexes are linked to your emotions and thoughts through a process called the fight or flight response.

What happens if you cry before sleeping? ›

Damages of crying before sleep on health:

Anxiety leads to the inability to sleep continuously, which makes the person feel exhausted and inabil to perform his actions the next day. 2. Bad psychological state accompanies a person throughout the day as a result of crying before sleep. 3.

Can tears have blood? ›

Haemolacria or blood in the patient's tears can find its source at any point along the anterior ocular surface. ocular adnexa, and lacrimal system (tear pathway), from tear production through tear drainage, including the lacrimal gland, the conjunctiva, the canaliculi or the lacrimal sac.


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