Why do Chili Peppers Burn: The Science Behind the Burn


One of the most known features of any chili pepper is the burn you feel when you bite in to one. Even the most ardent spicy food enthusiast cannot escape the burn that chili peppers leave on one’s mouth and tongue.

It’s the kind of burn that some people love, and many detest! So, what causes that burn? And why are some people addicted to it? And maybe most importantly, how does one prevent or get rid of that burning sensation?

We hope this post gets to the bottom of all the, uh, burning questions you might have about chili peppers!

What causes chili peppers to burn?

Chili peppers burn due to the presence of the chemical capsaicin. The capsaicin molecule has a long hydrocarbon tail which binds to pain receptor cells called TRPV1. The binding action sends signals to the brain that something is hot, thus we feel a burning sensation from eating hot peppers.

The main reason chili peppers cause a burning sensation is because of the presence of the chemical capsaicin. Capsaicin belongs to a group of compounds called vanilloids, which include other chemicals that have distinctive flavors and similar molecular structures, such as vanillin (in vanilla), eugenol (found in cloves), and zingerone (found in ginger).

The structure of the capsaicin molecule includes a long hydrocarbon tail, which enables it to bind with the lipoprotein receptor of cells, called TRPV1. At the heart of it, it is this binding action that essentially causes the burn we feel when we consume chili peppers. The protein’s job is to sense heat, so when the capsaicin’s tail binds with the cells’ receptors, it causes an influx of calcium in to the cells, which activates a pain signal. This signal gets passed from cell to cell, exciting pain receptors and alerting the brain, which responds by sending pain signals back to the affected area of the body causing our bodies to feel a burning sensation.

When you bite in to a chili pepper, say a Jalapeño or Habanero pepper, the chemical reaction has the same effect on your brain as you would have if your hand touched a hot surface. The capsaicin tricks our brain in to thinking we are being burned. It is likely that pepper plants evolved this way and created this burning defense mechanism to protect themselves from animals eating up their fruits.

Why do chili peppers burn your mouth?

As described above, the capsaicin in chili peppers is what leads to the burning sensation we feel when we eat chili peppers. The burn that we experience in our mouths is not exactly a flavor; rather it is a reaction of our body to the capsaicin chemicals, as a result of the activation of our bodies’ pain receptors. As soon as you bite into a chili pepper, the capsaicin molecules latch on to your cells’ pain receptors located in your lips, mouth, and tongue, which causes the burning sensation.

Why do chili peppers burn your skin?

If you’ve handled chili peppers with your bare hands and then rubbed your arms, or worse your eyes, you’ve probably experienced a sharp burning sensation in those areas right after. And often, this burning sensation can be more painful that the burn you feel when you eat chili peppers! So what causes your skin to burn when touching chili peppers? You guessed it! It’s out friend capsaicin! This chemical in chili peppers is the reason that you mouth, skin, eyes, etc. burn when you get in contact with spicy chili peppers. As mentioned above, capsaicin in chili peppers evolved this way as a defense mechanism for the plant, so that they could survive being eaten by pests.

Why do chili peppers burn when you poop?

We have now reached the TMI section of the blog post!

But seriously though, and don’t be shy here because you’re not alone, but how many of you have experienced a burning sensation while going to the bathroom after you have enjoyed a deliciously spicy meal?

The reason we feel this burning sensation is because the receptors we mentioned above, TRPV1, which helps us to react to hot weather and hot peppers, can be found all over our body—in our nose, mouth, skin, and also some nether regions like our anus and genitals. The reason why you might have the burn even upon the chili peppers exiting your body is because the chilies might not have been completely neutralized during digestion, and so the pain receptors in the anal glands might still get activated while you use the bathroom.

One way to protect yourself from this burn is to consume milk while you eat the chilies. This will not only ease the burning sensation in your mouth, but it also helps neutralize the capsaicin going through your body, so that it is less painful when it comes out the other end.

Can chili peppers burn your stomach?

We have all felt the burning sensation after eating hot peppers travel from your mouth, to your tongue and throat, and even down to your stomach. Some people with sensitive stomachs, or others who maybe have consumed too much spicy food, might even feel some discomfort in their stomach or intestines.

While this may be the case for many, it does not appear that spicy foods and peppers cause any physical damage in your stomach or actually burn your stomach in any way.

We all have TRPV1 receptors in many parts of our body, including throughout our gastrointestinal tract. This is why we feel that burning sensation throughout as the chili pepper moves through our body. These receptors are what set off the cooling response many people exhibit when eating chili peppers: sweating, flushing of the skin, and tears. Some others might actually start to feel their stomach cramp and will start to experience abdominal pain as their TRPV1 receptors work actively to neutralize the capsaicin.

A 2010 study in the Journal of Neurogastroenterology and Motility found that people with irritable bowl syndrome actually have more than the normal amount of TRPV1 receptors in their intestines. This is one reason why people with gastrointestinal afflictions are more sensitive to spicy foods and more likely to suffer from abdominal discomfort and pain when they consume hot peppers.

Can hot peppers burn you, physically?

Hot peppers cannot burn you physically or cause any physical damage to your skin and body.

Although the capsaicin present in the chili peppers may feel like your skin is burning, the effects are not the same as if you were to burn yourself from a source of fire. Once you wash away the capsaicin and pepper oils from your skin, you will not be left with any lasting scars or any indications that a chili pepper had harmed you.

Can eating hot peppers burn fat?

Several studies indicate that consuming chili peppers can help you to lose weight and burn fat. The capsaicin in the hot peppers can help you lose weight in three ways: it can help curb your appetite so you consume less food, it can help to speed up your metabolism, and it can help to burn calories.

Curb your appetite

According to this 2014 study, people who consume chili peppers with their meals might feel an increased feeling of being sated and will feel less hungry. The study implies that by consuming hot peppers, you will feel full quicker and consume less, thereby decreasing the number of calories you consume and improve your chances of losing weight.

Increase metabolism

If you’re really brave, you could try eating raw, fresh chilies as a means to help you lose weight. This study from 2003 suggests that consuming fresh hot peppers can actually increase your metabolic rate for up to 30 minutes after you eat those peppers. People with high metabolisms tend to be slimmer because their body is more efficient at converting nutrients in to energy, rather than storing them as fat.

Burn calories

Finally, eating a spicy pepper can help to burn calories more actively. This 2011 study’s results suggests that consuming a hot pepper causes your body temperature to rise which forces your body to try and cool itself down. We see this manifest in sweating and the flushing of the cheeks. This reaction from your body is calorie-intensive, so you’re actively burning calories as your body sweats in response to the heat!

How long does the burn from chili peppers last?

The length of the burn from chili peppers will depend on the chili pepper, with hotter peppers generally causing the burning sensation to last longer. The burning sensation in your mouth will usually last anywhere between a few seconds to a number of minutes, depending on the chili pepper. For example the burn from a Ghost Pepper lasts far longer than a Jalapeño pepper.

If you handle hot peppers, the burning feeling, or “hot pepper hands”, can last up to 24 hours or even longer, depending on how long you handled the peppers. The length of time the burning sensation lasts is also dependent on other factors, such as the severity of the burn, sensitivity of your skin, and whether or not your skin has an allergic reaction to the pepper.

How to get rid of the burning from hot peppers in your mouth?

Although your first reaction when you feel the burn of chili peppers in your mouth might be to reach for that cool, refreshing glass of water, there are four better alternatives that will be quicker and more effective in reducing the burn.

Dairy

At the top of the list is dairy. Milk or plain, cool yogurt are probably your best friends when it comes to healing your mouth from hot chili peppers. And this remedy is not just an old wives’ tale—there is actual science to back this up!

Dairy contains a protein called casein, which helps to break down the capsaicin present in hot peppers. Because casein is non-polar, like capsaicin, they bind to each other more easily than water and capsaicin (because water is made up of polar molecules), which is what makes dairy a more effective remedy than water. By binding with the capsaicin, the dairy prevents the capsaicin from binding with your mouth’s pain receptors, which reduces the burn.

Honey or Sugar

If you’re lactose-intolerant or vegan, a better alternative for you might be sugar or honey. Not only will the natural sweet taste help to reduce the spiciness from the peppers, but the sugar and honey also help absorb the oils from the capsaicin, which relieves the pain.

Starch

Rice, bread, or even boiled potatoes can also come in handy to help prevent chili pepper burn. Starch can absorb the oils from the capsaicin and prevent them from latching on to your mouth’s pain receptors.

Citrus

This may sound counter-intuitive, but citrus fruits act as alkaline agents when digested, and can help neutralize the acidity of hot peppers. Fruits like lemons, tomatoes, and pineapples have these properties and can provide relief for your mouth after you consume hot chili peppers.

How to stop the burning from chili peppers on your skin?

If your skin has direct contact with a hot pepper, you might feel a burning sensation immediately, or sometimes hours later. Here are a few remedies that can help prevent the spread and reduce the intensity of the burn.

Contain the burn

The first thing you should try and do is contain the burn and avoid spreading it all over your body. The easiest way to do this is to be careful to not rub the affected area on other parts of your body. So if you have handled hot peppers with your hands, be sure to avoid touching other parts of your body.

Use dish soap and lukewarm water

Dish soaps are created to remove the oils from cooking and are therefore more effective at removing the capsaicin oils from your skin than regular hand soap. Make sure not to wash your hands in hot water, as that will just aggravate your skin further and make the burning sensation feel worse.

Try using oil

Cooking oils, like olive or vegetable oil, can help to dissolve capsaicin. Try massaging a small amount of the oil on the affected area, and then wash with it off with regular hand soap and lukewarm water.

Create a baking soda or cornstarch paste

As we mentioned above, starches can help neutralize capsaicin and create a barrier between the chili oils and our skin’s pain receptors. Combine a small amount of cornstarch or baking soda with water to create a paste. Apply the paste to the affected areas and let it dry, before rinsing off with water.

Apply dairy

Dairy can be effective in reducing chili pepper burns in both your mouth and your skin. Not only will yogurt or milk from the fridge have a cooling sensation on the burning skin, but the presence of the protein casein will also help neutralize the burn from capsaicin. Whole fat milk or yogurt will work better than the low fat or skim varieties.

Diluted vinegar

The National Capital Poison Center recommends diluting vinegar with water and soaking the affected body parts in that mixture to help reduce the pain from chili burns.

Very mild bleach solution

Chef Alton Brown recommends using a 5-to-1-part mixture of bleach and water to help reduce the burn on your skin from hot peppers. The bleach interacts with the capsaicin and makes it more water soluble, which is then easier to rinse away.

Use an ice pack

A simple way to help relieve your burning skin is to apply a cold ice pack or compress

Why is the burn from chili peppers addictive?

Although many have studied and investigated this question, there does not seem to be a simple answer to the question.

Unlike sweet, salty, or sour, spiciness is not a flavor, but rather an activation of the pain receptors in your mouth, which means it’s your body reacting to pain. So why do so many people like spicy food and the accompanying burn?

Although we say some people are “addicted” to the burn from spicy foods, the reality is that the chemical capsaicin actually does not have any addictive qualities. Unlike bitter coffee or harsh tobacco that might not taste good to us, capsaicin just causes burn without the same addictive qualities.

Scientists suggest that it’s the thrill we feel from the burning sensation and pushing ourselves to the limits that humans like spicy foods. Actively seeking out that pain and thrill, much like the reasons why some of us like hair-raising scary movies or even jumping out of planes, is why humans actively eat hot chili peppers even though they cause our mouths and skins to burn in the process.

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