What is caffeine?

Caffeine is the world’s most widely used psychoactive substance and has been around since time immemorial. It is a naturally occurring compound in different parts of a variety of plants native to various parts of the world. This means we can find it in drinks derived from those plants like tea, coffee or maté. Although some people consciously consume caffeine for its benefits, for most people it is so much of a habit, it has become part of their culture.

Where does caffeine come from?

According to legend, caffeine has been used as early as 3000 BCE when a Chinese emperor discovered tea by accident.[1] On the other side of the world the earliest evidence of caffeine from cocoa beans was found in a Mayan pot from 600 BCE.[2] Modern use of caffeine began when people started drinking coffee and tea on a daily basis. Although accounts differ, drinking coffee originated somewhere around Yemen and had spread through North Africa and the Middle East to Europe by the end of the 16th century.[3] Around the same time tea was introduced to western culture by the Chinese and popularized in Europe through trade by the Dutch East India Company.[4] With the advent of modern chemistry during the age of revolution, caffeine was first isolated from coffee in 1819 by the German chemist Friedlieb Ferdinand Runge.[5] Two years later, Pierre Jean Robiquet first analyzed and described the properties of caffeine. Yet it would take another 74 years before Hermann Emil Fischer discovered how caffeine could be synthesized from its chemical components.[6] Part of which, he was awarded a Nobel Prize for in 1902.

What are the effects of caffeine?

Caffeine works mainly by suppressing adenosine receptors, a compound which induces a relaxed or sleepy sensation in the central nervous system (CNS).[7] To a smaller extent, cafeïne has effects on a variety of other neurotransmitters including dopamine[8] and serotonin.[9] Both of these mechanisms contribute to a breadth of health benefits for which there is ample evidence. When taken orally, the effects of caffeine usually can be felt after an hour and lasts for three to four hours. Many of the effects of caffeine depend on the user’s tolerance. Daily caffeine users may therefore be unable to benefit from these effects.


  • Improved reaction time
  • Reduced fatigue
  • Increased wakefulness
  • Improved concentration
  • Improved motor coordination


  • Improved power output
  • Improved endurance
  • Increased adrenaline
  • Increased blood pressure
  • Increased cortisol

How to use caffeine?

Caffeine can be taken through beverages rich in caffeine, by supplementing your own drinks with caffeine powder or in pill form. Though all three have different pros and cons, all caffeine intake should be tailored to individuals. Caffeine from beverages are widely available and easy to use but differ in caffeine content from drink to drink and might also include unwanted micro- or macronutrients. Caffeine powder might be easy to add to whatever drink or food you want, but it can be risky if not handled with care. Multiple people have died of an accidental overdose.[10, 11] Caffeine pills are less risky, widely available but might offer less possibilities in the way of really fine-tuning your preferred dosage.

How much caffeine to use?

Different effects require different amounts of caffeine but if you have never taken caffeine before it can be wise to start with a low dose of 100 mg. 200 mg is often used as a fat-burning supplementation and an increase in strength occurs at higher doses of 500 mg and above.

Interactions of caffeine

Even though caffeine is safe enough for billions of people to drink on a daily basis, caffeine is a stimulant just like amphetamines or cocaine. Taking multiple stimulants may increase the strain on the heart and bring about a greater risk of heart failure.

  • Caffeine increases the neurotoxic effects of MDMA [12]
  • Caffeine does not affect the effects of alcohol but alcohol does diminish the effects of caffeine[13]
  • Caffeine is eliminated from the body faster 56% when also smoking tobacco.[14]
  • Contraceptives like the birth control pill can slow the elimination of caffeine from the body[15]

Related articles


  1. [1] Evans, J. C. (1992). Tea in China: The History of China’s National Drink (Contributions to the Study of World History). Praeger.
  2. [2] Watson, R., Preedy, V. R., & Zibadi, S. (2012). Chocolate in Health and Nutrition. Amsterdam University Press.
  3. [3] Weinberg, P. H. D. B. A., Bealer, B. K., Weinberg, P. D. B. A., PhD, & Bennett Alan Weinberg, B. K. B. (2001). The World of Caffeine. Routledge.
  4. [4] Hoh, E., & Mair, V. H. (2009). The True History of Tea. Thames & Hudson.
  5. [5] Runge FF (1820). Neueste phytochemische Entdeckungen zur Begründung einer wissenschaftlichen Phytochemie. Berlin: G. Reimer.
  6. [6] Fischer, E., & Ach, L. (1895). Synthese des Caffeïns. Berichte Der Deutschen Chemischen Gesellschaft, 28(3), 3135–3143.
  7. [7] Nehlig, A., Daval, J. L., & Debry, G. (1992). Caffeine and the central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects. Brain Research Reviews, 17(2), 139–170.
  8. [8] Solinas, M., Ferré, S., You, Z. B., Karcz-Kubicha, M., Popoli, P., & Goldberg, S. R. (2002). Caffeine Induces Dopamine and Glutamate Release in the Shell of the Nucleus Accumbens. The Journal of Neuroscience, 22(15), 6321–6324.
  9. [9] Yokogoshi, H., Tani, S., & Amano, N. (1987). The Effects of Caffeine and Caffeine-containing Beverages on the Disposition of Brain Serotonin in Rats. Agricultural and Biological Chemistry, 51(12), 3281–3286.
  10. [10] Stampler, L. (2014, July 1). Prom King Died From Caffeine Powder Overdose. Time.
  11. [11] O’Neill, M. (2019, July 10). Caffeine Powder Overdose Leaves 21-Year-Old Dead—Here’s What to Know. Health.Com.
  12. [12] Górska, A. M., Kamińska, K., Wawrzczak-Bargieła, A., Costa, G., Morelli, M., Przewłocki, R., Kreiner, G., & Gołembiowska, K. (2017). Neurochemical and Neurotoxic Effects of MDMA (Ecstasy) and Caffeine After Chronic Combined Administration in Mice. Neurotoxicity Research, 33(3), 532–548.
  13. [13] Liguori, A., & Robinson, J. H. (2001). Caffeine antagonism of alcohol-induced driving impairment. Drug and Alcohol Dependence, 63(2), 123–129.
  14. [14] Zevin, S., & Benowitz, N. L. (1999). Drug Interactions with Tobacco Smoking. Clinical Pharmacokinetics, 36(6), 425–438.
  15. [15] Benowitz, N. L. (1990). Clinical Pharmacology of Caffeine. Annual Review of Medicine, 41(1), 277–288.
Other namesCoffee
EffectsFocus, Motivation, Energy
Half-life5 hours (1.5 - 9)
Total2 - 12 hours