What is Caffeine? - Structure & Side Effects

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  • 0:04 Caffeine Definition
  • 1:24 Caffeine Structure
  • 1:55 Caffeine Function
  • 2:52 Caffeine Side Effects
  • 5:20 Lesson Summary
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Lesson Transcript
Instructor: Jo Kenney

Jo has experience as an instructional designer and courseware developer and has a doctorate in Education Technology.

Caffeine is one of the most commonly used drugs in the world, but what is it? Found in coffee, tea, soda, some medications, and energy drinks, the positive and negative side effects of caffeine use are important to understand. This lesson describes the chemical composition and side effects of caffeine.

Caffeine Definition

Whether it's a morning cup of java, a cola with a value meal, an energy drink to beat the afternoon slump, energy pills to make it through finals week, or a chocolate bar to relieve a stressful day, most of us have used the drug caffeine at some time during our lives. Yes, caffeine is a drug. A drug is a chemical substance that has a biological effect, and caffeine, while naturally occurring, does have an effect on the body; it can even cause dependency, and for some, there are even withdrawal symptoms. Caffeine is a stimulant and is considered psychotropic as it also contains mood altering properties.

Caffeine is one of the most widely used legal drugs in the world, but even if you have a three latte a day coffee habit you may not understand exactly what caffeine is. Caffeine is derived from a natural insecticide found in over 60 plants. It is found in coffee beans, tea leaves, yerba mate, guarana berries, kola nuts (used in colas), and cacao pods (used to make chocolate), but can also be synthesized in chemical labs to add to food or drugs. Caffeine contains methylxanthines, a molecular compound derivative of xanthine. So what is xanthine? It is a high-protein purine base found in animal or plant tissues.

Caffeine Structure

The medical name, derived from its molecular structure, is 1,3,7-trimethylxanthine. The chemical is also known as caffeine, theine, mateine, guaranine, or methyltheobromine. Its chemical formula is C8 H10 N4 O2. This means it is made of 8 carbon atoms, 10 hydrogen atoms, 4 nitrogen atoms, and 2 oxygen atoms. A full and skeletal formula for caffeine is displayed below.

Caffeine model
Caffeine skeletal formula C8H10N4O

Caffeine Function

Caffeine's effects are milder than other stimulants, such as amphetamines and cocaine, but it does influence the same channels in the brain. This effect on the brain is one of the reasons caffeine is addictive. In fact, caffeine actually changes brain chemistry, increases dopamine levels, and causes blood vessels in the brain to constrict. By releasing adrenaline, you feel a boost of energy and alertness; however, once the effects wear off, feelings of fatigue and irritability may increase.

Caffeine works by stimulating the central nervous system (CNS), heart, muscles, and the centers that control blood pressure. Caffeine can raise blood pressure, but may not have this effect in people who use it regularly. For some, caffeine can increase urine flow or even induce diarrhea. Like most drugs, the effects of caffeine will vary from person to person and a person's tolerance to caffeine can increase over time.

Caffeine Side Effects

Caffeine has a number of side effects, some good and some that can cause serious medical issues. For most, regular and appropriate use of caffeine is safe, but at high-levels, it can lead to medical troubles and even death. As a stimulant, caffeine can increase your heart rate and blood flow increasing alertness and energy. This stimulating effect of caffeine can cause insomnia, shakes or tremors, trouble staying asleep, agitation, rapid or uneven heartbeats, raised blood pressure, along with more severe side effects, including headaches, anxiety, panic-attacks, ringing in the ears, vomiting, and/or dizziness. For some people, caffeine can actually increase food cravings and feelings of stress.

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