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What is Caffeine?


An image of Coffee Chocolate Truffles coated in cocoa powder and chopped pecans.

These truffles contain chocolate and coffee -- two natural sources of caffeine.

Marko Goodwin
Caffeine is a naturally occurring chemical compound. Caffeine's systematic name is 1,3,7-trimethylxanthine or 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione and its chemical formula is C8H10N4O2. Caffeine is also commonly known as coffeine, theine, mateine, guaranine and methyltheobromine. (Although some sources claim that these are separate chemical compounds they are, in fact, caffeine.)

Where is Caffeine Found?

Caffeine is found in coffee, tea, chocolate and yerba mate, as well as a 56 other herbs and plants. It is also added to some types of foods and drinks (such as colas and energy drinks) and drugs (such as Excedrin).

How Does Caffeine Work?

Caffeine reduces the body's inclination toward feeling tired in two main ways.

First, caffeine mimics a naturally occurring chemical called adenosine and binds to the brain's adenosine receptors and the adenosine receptors in other organs of the body. The receptors are blocked by caffeine, which prevents adenosine from binding to them. Adenosine's role in the brain is to slow down nerve impulses and cause drowsiness, so caffeine's presence inhibits this reaction and increases alertness and responsiveness. In their stimulated state, nerve cells can release the hormone epinephrine (adrenaline), which increases heart rate and blood pressure, increases blood flow to muscles, decreases blood flow to the skin and organs, and prompts the liver to release glucose (a form of liquid sugar which supplies the body with energy).

Second, caffeine increases dopamine levels in the brain. Dopamine is a naturally occurring chemical responsible for feelings of well-being and happiness. Therefore, caffeine tends to improve one's mood. This is thought to be the primary reason that caffeine is an addictive substance.

How Much Caffeine is Safe?

For most people, about 300 mg of caffeine a day is a healthy level of caffeine consumption. That is roughly equivalent to three cups of coffee. However, caffeine levels in coffee, tea and chocolate vary widely, and some people experience symptoms of excess caffeine consumptions after consuming as little as 100 mg of caffeine, so be sure to check how much caffeine is in your favorite products if you are concerned about your caffeine intake. (Side note -- Contrary to popular belief, dark roast coffee generally has less caffeine than light roast coffee.)

Ten to 20 grams of caffeine is generally considered a lethal dose, though the exact amount varies from person to person. However, death by caffeine is extremely rare, and is usually intentional.

For more information, see symptoms of too much caffeine.

What Does Decaf Mean and How Does Decaffeination Work?

"Decaf" means that some or most of the caffeine in a caffeine-containing substance has been removed. Coffee can be decaffeinated in several ways. Tea can be decaffeinated with chemical processing or carbon dioxide processing. There is also a pervasive myth surrounding how to decaffeinate tea with hot water.

What is Pure Caffeine Like?

Once isolated, caffeine is a crystalline white powder with an intensely bitter flavor. This powder is a natural byproduct of tea baking, coffee roasting and tea / coffee decaffeination. Pure caffeine is often reused and mixed into energy drinks, colas and medications.

Caffeine was first isolated from coffee by the German chemist Friedrich Ferdinand Runge in 1819.

Is Caffeine a Drug?

By the generally accepted definition of "drug," yes, caffeine is a drug. It is a stimulant and it can be very addictive when consumed in excess with regularity. Caffeine is not only a drug; it is the most popular drug in the world. Around 90 percent of Americans consume caffeine in some form every day, and as a nation, the U.S. consumes over 450,000,000 cups of coffee daily.

If you're interested in cutting down on caffeine, read up on how to reduce caffeine intake, caffeine withdrawal symptoms and caffeine headaches.

Can Caffeine Help Someone Sober Up?

There is a common myth that caffeine (or coffee) will help a drunk person sober up. This has been proven to be completely false, and consuming caffeine while drunk can actually cause more harm than good. (For example, if someone has drunk enough that their natural physical reaction is to pass out and, by default, stop drinking, then caffeine can inhibit this reaction and allow them to continue drinking. In several prominent cases, high-caffeine alcoholic beverages have been associated with severe alcohol poisoning.)

Which Drinks are High in Caffeine?

If you're looking for an extra dose of caffeine, check out these high-caffeine drinks:

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