What Is Caffeine?

What is caffeine

When it comes to caffeine, what do you immediately think of? Yes, coffee. But did you know that there are many other daily beverages that contain caffeine, Including brewed tea, energy drinks, soft drinks, cocoa drinks, and even chocolate milk?

You can also find caffeine in some prescription or over-the-counter medicines, such as cold medicines, anti-allergic drugs, and painkillers. It is also a common element in weight loss supplements.

Are you amazing to hear that? Today we are going to talk about something about caffeine, including what caffeine exactly is, what effects it has, how it works, what benefits it has for health, and what are the hazards of excessive intake. Okay, let’s get started.

As mentioned earlier, some beverages, foods, and even medicines in life contain caffeine. So what exactly is it? In fact, caffeine is naturally present in the seeds, nuts, or leaves of certain plants. It is a natural stimulant, most commonly found in tea, coffee, and cocoa plants. It works by stimulating central nervous in the brain to help you hold alert and prevent fatigue.

Historians date back to the first tea brewed in 2737 BC. After that many years, it was reported that an Ethiopian shepherd discovered coffee. He noticed that coffee gave goats extra energy.

Caffeinated soft drinks entered the market in the late 19th century, followed by energy drinks. Today, 80% of people in the world consume caffeinated products every day.

In a word, caffeine is a natural stimulant and is widely consumed in the world. It can help you stay awake and avoid fatigue.

How Does It Affect Your Body?

Once people consume caffeine, it will be quickly absorbed from the intestines into the blood, enter the liver, and be broken down into compounds that can affect the functions of various organs.

In fact, the main effect of caffeine is to affect the brain. It blocks the effects of adenosine, a neurotransmitter that relaxes the brain and makes you feel tired.

Under normal circumstances, adenosine levels will increase throughout the day, making you more tired and making you want to sleep. In other words, caffeine helps you stay awake by blocking this effect.

It can also increase adrenaline levels in the blood and increase the level of neurotransmitters dopamine and norepinephrine in brain activity. These effects further stimulate the brain and promote states of arousal, alertness, and concentration.

Caffeine tends to work quickly. The caffeine content in a cup of coffee may only take 20 minutes to reach the blood, and it takes about an hour to take effect fully.

In a word, caffeine mainly affects the brain. It stimulates the brain by blocking the effects of adenosine and keeps you awake.

In addition, what other effects does it have?

The Benefits Of Caffeine: Moderation Consumption

Studies have shown that proper doses of caffeine can improve mood and brain function, improve concentration, memory, reaction time, and motor coordination.

We already know that caffeine can block adenosine. It leads to a relative increase in other signaling molecules, such as norepinephrine and dopamine. This change in brain information is believed to benefit your mood and brain function.

One study showed that after participants intake 37.5-450 mg of caffeine, their alertness, reaction time, and short-term recall improved.

When it comes to emotions, more caffeine is not necessarily better.

Another study pointed out that unless the second cup of coffee is consumed at least 8 hours after the first cup, there will be no further benefits.

Drinking 3-5 cups of coffee a day can also reduce the risk of brain diseases such as Parkinson’s and Alzheimer’s by 28-60%.

It should also be noted that coffee and tea contain other biologically active compounds that may be beneficial.

Because caffeine can stimulate the central nervous, it can increase metabolism level by approximately 11% and fat burning by about 13%.

In fact, 300 milligrams of caffeine per day can allow you to burn an extra 79 calories a day. This amount may seem small, but it is similar to the calorie surplus that the average American gains 2.2 pounds per year. Of course, this does not include the extra ingredients contained in your coffee, such as milk, chocolate syrup, etc. Otherwise, your calories will only be more.

In terms of exercise, caffeine may increase the use of fat as fuel.

This is beneficial because it can help the glucose stored in the muscles last longer and may delay your muscles from reaching exhaustion.

Caffeine may also improve muscle contraction and increase tolerance to fatigue. Researchers have noticed that 2.3 milligrams per pound of weight 1 hour before exercise can improve endurance performance by up to approximately 5%. An amount as low as 1.4 milligrams per pound of body weight may be sufficient for the benefit.

More importantly, research reports claim that there are similar benefits in team sports, high-intensity exercise, and resistance sports.

Finally, it may also reduce fatigue perception by approximately 5.6% during exercise, making exercise feel easier.

In addition, moderate caffeine intake has been shown to have many health benefits associated with lowering the risk of type 2 diabetes, lowering the cortisol response, and lowering the risk of dementia.

Although you may have heard that caffeine does not increase the risk of heart disease, in fact, there is evidence that men and women who consume approximately 100-400 mg of caffeine have a 16-18% lower risk of heart disease.

One thing to remember is that caffeine may slightly increase blood pressure in some people. However, this effect is usually small, and for most people, this effect tends to disappear when they drink coffee regularly.

It may also prevent diabetes.

One review noted that those who drank the most coffee had a maximum reduction of 29% in their risk of developing type 2 diabetes.

Is Caffeine Bad For You? - If Excessive Consumption

You may notice that some of the benefits of consuming caffeine mentioned above are based on one premise – moderate intake.

Then you may ask if there will be some harm if you over intake it. The answer is yes.

Problems caused by excessive intake include anxiety, digestive tract irritation, difficulty sleeping, excessive excitement, etc.

However, what you need to know is that the amount of caffeine required to produce these effects varies from person to person, depending on body size, health status, and tolerance level. If you are sensitive to caffeine and are prone to over-excitement, you may need to stay away from coffee.

In addition, caffeine easily crosses the placenta, which may increase the risk of miscarriage or low birth weight. Pregnant women should be limit their intake.

Caffeine can also interact with some drugs.

People who take the antidepressant or the muscle relaxant should avoid caffeine, as these drugs may increase its effects.

Both the United States Department of Agriculture (USDA) and the European Food Safety Agency (EFSA) believe that 400 mg of caffeine per day is safe. It is worth noting that a single dose of 500 mg of caffeine one time has been reported to cause a fatal overdose.

According to the American College of Obstetricians and Gynecologists (ACOG), pregnant women should be limited to 200 mg in their daily caffeine consumption.

If you want to know the moderate and safe intake, you should consult a doctor based on your health.

How To Control The Caffeine Daily Intake?

By this point, we have learned everything about caffeine. However, there is another point that when you start to drink a cup of coffee or a cup of tea every day, you may be worried whether your caffeine today exceeds the standard.

Therefore, you also need to know the caffeine content of common caffeinated beverages. You can get them in the following ways:

Final Thoughts

Without talking about daily intake, it is wrong to assume that caffeine is good or bad.

As a coffee lover, enjoy your coffee time within a safe range, healthy and happy.


The European Food Safety Agency (EFSA) and the U.S. Department of Agriculture (USDA) consider that 400 mg of caffeine per day is safe for most healthy adults.

For some special populations, such as pregnant women, according to the regulations of the American College of Obstetricians and Gynecologists, the daily intake should be limited to 200 mg.

Medical Disclaimer: As the body size, health status, and tolerance level are different, the daily intake may vary from person to person. If you want to know your safe value, you should consult a doctor based on your health.

Common beverages containing caffeine include coffee, brewed tea, espresso, energy drinks, soft drinks, cocoa drinks, and more.

Foods containing coffee include chocolate and chocolate-flavored foods, some chewing gum, and coffee-containing foods (such as coffee ice cream, tiramisu).


  1. U.S. Department of Health and Human Services and U.S. Department of Agriculture. (8th Edition. December 2015). “2015 – 2020 Dietary Guidelines for Americans”.  
  2. U.S. Food and Drug Administration. “Spilling the beans: How much caffeine is too much “.  

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