Caffeine is a central nervous system stimulant (psychoactive) substance found in approximately 60 different plants, most notably in coffee beans, tea leaves, and cocoa beans. Caffeine is a natural pesticide (fights against harmful insects) and herbicide (fights against excess weeds) at the same time. That is why the aforementioned plants produce this substance to protect themselves from pests.

In the human body, caffeine blocks the action of a chemical substance called “adenosine”, which is the main cause of drowsiness and fatigue. And caffeine is an artificial stimulant of “vigor”. Even when breathing the aroma of freshly ground coffee, a person immediately feels vigor and a sense of well-being. Since Adenosine is synthesized in almost all living organisms, it should be noted that Caffeine has the same effect on animals as it does on a human organism.

Caffeine is a white bitter organic compound that is classified as “Generally Recognized As Safe (GRAS)” by the US Food and Drug Administration. And while it’s generally considered safe, consuming too much caffeine can lead to dangerous consequences. The daily limit of caffeine for adults is set by the Canadian Department of Health (Health Canada) at 400 milligrams, and a dose of 10 grams of caffeine per day is considered “Deadly Toxic”.

Some of the possible effects of caffeine exposure are listed in the table below.


Moderate and regular use of Caffeine Irregular and excessive use of Caffeine
• Stimulates mental activity • May cause confusion and mental retardation
• Reduces fatigue • May cause sleep disturbance
• Reduces the level of stress in the body • May cause high stress background
• Reduces muscle pain • Accelerates the work of the heart
• Can regulate blood pressure • May increase blood pressure
• May stimulate sexual activity • May prevent women from becoming pregnant
• Can regulate the body’s metabolism • May cause intestinal disturbances
• Has an analgetic effect • May cause headache
• May increase well-being • Can be addictive


Caffeine is contained not only in our favorite cup of coffee, but also in a number of other drinks and foods. Here are some of them:

Food Serving Size Caffeine Content
• Decaffeinated coffee 125 milliliters 1-5 milligrams
• Tea 150 milliliters 20-45 milligrams
• Hot chocolate 150 milliliters 2-7 milligrams
• Carbonated drinks 330 milliliters 30-48 milligrams
• Energy drinks 330 milliliters 70-120 milligrams
• Chocolate bar 30 grams 5-36 milligrams
• Dark chocolate 30 grams 20-120 milligrams