What is Caffeine: Definition and 30 Discussions

Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is the world's most widely consumed psychoactive drug. Unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world. There are several known mechanisms of action to explain the effects of caffeine. The most prominent is that it reversibly blocks the action of adenosine on its receptors and consequently prevents the onset of drowsiness induced by adenosine. Caffeine also stimulates certain portions of the autonomic nervous system.
Caffeine is a bitter, white crystalline purine, a methylxanthine alkaloid, and is chemically related to the adenine and guanine bases of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is found in the seeds, fruits, nuts, or leaves of a number of plants native to Africa, East Asia and South America, and helps to protect them against herbivores and from competition by preventing the germination of nearby seeds, as well as encouraging consumption by select animals such as honey bees. The best-known source of caffeine is the coffee bean, the seed of the Coffea plant. People may drink beverages containing caffeine to relieve or prevent drowsiness and to improve cognitive performance. To make these drinks, caffeine is extracted by steeping the plant product in water, a process called infusion. Caffeine-containing drinks, such as coffee, tea, and cola, are consumed globally in high volumes. In 2020, almost 10 million tonnes of coffee beans were consumed globally.Caffeine can have both positive and negative health effects. It can treat and prevent the premature infant breathing disorders bronchopulmonary dysplasia of prematurity and apnea of prematurity. Caffeine citrate is on the WHO Model List of Essential Medicines. It may confer a modest protective effect against some diseases, including Parkinson's disease. Some people experience sleep disruption or anxiety if they consume caffeine, but others show little disturbance. Evidence of a risk during pregnancy is equivocal; some authorities recommend that pregnant women limit caffeine to the equivalent of two cups of coffee per day or less. Caffeine can produce a mild form of drug dependence – associated with withdrawal symptoms such as sleepiness, headache, and irritability – when an individual stops using caffeine after repeated daily intake. Tolerance to the autonomic effects of increased blood pressure and heart rate, and increased urine output, develops with chronic use (i.e., these symptoms become less pronounced or do not occur following consistent use).Caffeine is classified by the US Food and Drug Administration as generally recognized as safe (GRAS). Toxic doses, over 10 grams per day for an adult, are much higher than the typical dose of under 500 milligrams per day. A cup of coffee contains 80–175 mg of caffeine, depending on what "bean" (seed) is used, how it is roasted (darker roasts have less caffeine), and how it is prepared (e.g., drip, percolation, or espresso). Thus it requires roughly 50–100 ordinary cups of coffee to reach the toxic dose. However, pure powdered caffeine, which is available as a dietary supplement, can be lethal in tablespoon-sized amounts.

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  1. Lachlan

    Chemistry Synthesis of Caffeine from Theobromine

    Most of what I'm going off is from this article here - https://www.sciencedirect.com/science/article/pii/S0187893X15720926#bib0115. This presents methyl iodide as safer than dimethyl sulphate, which is true and helpful, but not safe enough for me to be able to use it at school. I understand its...
  2. G

    Dissolving caffeine in room temperature water

    Hello everyone, I have been trying to dissolve caffeine in water for a few days now. I am trying to dissolve approx. 500mg of caffeine in approx. 10ml of water, but I am encountering the problem that the solution turns into a paste. If I heat the water beforehand, the caffeine dissolves well at...
  3. kyphysics

    Is Needing Caffeine to Be Alert Problematic?

    Yes, I know I should consult with my doctor (and plan to). Nonetheless, I'm wondering: a.) How common is it for someone to need caffeine to get alert? b.) If it is practically daily, does that seem problematic? For me, being alert and not feeling tired certainly varies with sleep. Less...
  4. Delta2

    Caffeine Isomers and Their Effects on the Nervous System

    I noticed that different brands of espresso coffee have different effect on my nervous system. Some are really good in the sense that they wake me up and make me feel fresh and dynamic, while others do nothing, and others make me really jumpy and nervous and stressed. Why is that? I am not good...
  5. ORF

    Medical Why polyphenols make caffeine (from tea) work slower?

    Hello Why polyphenols make caffeine (from tea) work slower than caffeine from coffee? Thank you for your time. Regards, ORF
  6. shimun

    Neutralizing Caffeine in the Human Body: Tips and Tricks

    hello folks what can neutralize caffeine in human body ? thank you very much
  7. P

    What is your experience with caffeine?

    Hello guys, I once again come to ask of a concern that has been worrying me for some time. Last semester as I took much lighter coursework, I had the luxury of having a lot of time to figure problems out, and only consumed a can of energy drink before tests for the assurance. I felt that I was...
  8. N

    Coffee/caffeine and genius within

    I would like to know how many geniuses didnt drink caffeine in a daily basis if any when they did their major work? Or current geniuses? Ive heard rumours that Tesla didnt drink coffee after realizing it affected his imagination, but I don't know if he continued drinking it later on. I read...
  9. mnmman

    BP & MP of Caffeine: 178°C & 236.2°C

    Pubchem says the BP of caffine is 178 deg C (sublimes) and the melting point is 236.2 deg C. Below is the only phase diagram I found for caffeine. Aren't the MP and BP measured at 1 atm? If so according to this phase diagram it shouldn't sublimate correct? Assuming the phase diagram is wrong...
  10. Ygggdrasil

    Caffeine & Obesity: Scientists Explore Impact on Brown Fat

    Scientists studying obesity have had great interest in brown fat, adipose tissue that actually helps burn fat (for example, to generate body heat in the cold). Studies suggest that higher levels of brown fat correlate with lowered risks for obesity and diabetes, and scientists are studying...
  11. J

    Exponential problem: caffeine dosage

    If the concentration of caffeine in a system at any given time is given by the equation y(t)=De^-kt where dy/dt=-kt is the clearence rate (re-arranged and integrated to form the above equation) and the concentration of caffeine in the system at t=0 is D, then calculate k if: After one hour...
  12. M

    Determination of oxidation numbers in caffeine

    Hi, The formula of caffeine is C8H10N4O2. The oxidation numbers of O & H are -2 & +1 according to the book. How do I determine the oxidation numbers of C or N. Note: The substance is a molecular substance so we cannot apply the following rule: "the oxidation number of an atom in a monatomic...
  13. L

    Caffeine Soap; does it really work?

    Evening all, I've been curious about these caffeine soaps lately and thought that this would be the place to discuss about it. My almost-favorite website United Nuclear claims: "As it turns out, our good old friend Caffeine reaches the bloodstream faster through skin absorption...
  14. T

    Determine the concentration/purity of Caffeine in a precipitate

    So, I've extracted a small amount of (hopefully) caffeine from coffee via solvent extraction with hexane. Quick note before i go on, I know that this is possibly not the best method - however I am trying to determine the best method of caffeine extraction via experiment. Anyways, to...
  15. C

    Calculate Caffeine Molecular Formula: C8H10N4O2

    Homework Statement Caffeine, a stimulant found in coffee, tea, chocolate, and some medications, contains 49.48% carbon, 5.15% hydrogen, 28.87% nitrogen, and 16.49% oxygen by mass and has a molar mass of 194.2. Homework Equations Determine the molecular formula of caffeine. The...
  16. M

    Determination of Caffeine in Moutain Dew

    We did an experiment (link provided below), where we were to determine the concentration of caffeine in Mountain Dew. We made 3 standards and measured their absorbance along with the unknown (the mountain dew sample) and we graphed these results to find the concentration of caffeine in Mountain...
  17. C

    Medical Caffeine & Nicotine: Effects on Brain - What's the Difference?

    do caffeine and nicotine have the same on the brain? if not, how do they differ?
  18. nismaratwork

    Twinkie Defense, Step Aside: Caffeine Defense

    I must admit, that this surprised me. I you're wrecked on meth or cocaine and kill someone, its still murder,m but somehow this is a defense being offered in a court of law: http://news.blogs.cnn.com/2010/09/20/murder-defense-too-much-caffeine/?hpt=T2 Twinkie defense, meet Caffeine (and sleep...
  19. X

    Medical Effects of Caffeine on Brainwave Synchronization?

    I know that Caffeine gives a boost in the amount of Beta-Waves in the brain, but what does it do to the Synchronicity of brainwaves between the 2 Hemispheres? It's well known that a brain with higher synchronicity is more efficient than a brain with uneven brainwave synchronicity... Since...
  20. P

    Caffeine's Impact on Squirrels: Fact or Fiction in Hoodwinked & Over the Hedge

    Hello everyone :smile: Is there any special effect of Caffeine on Squirrels ? with reference to Hoodwinked & Over the hedge (Animated Cartoons) In these animated cartoons, squirrels get super-fast by drinking coffee! Is this really true?
  21. H

    Chemistry What is the Empirical and Molecular Formula of Caffeine?

    Homework Statement What is the Empirical and Molecular Formula of caffeine, given these information: 0.376g caffeine would yield to 0.682 CO2 , 0.174g H2O and 0.110g N. The molecular weight if caffeine is 194 g/mole. Homework Equations --- The Attempt at a Solution 0.682 CO2...
  22. P

    Methods for Removing Caffeine: Column Chromatography, Distillation, and More

    Homework Statement what are the types of methods to use to remove caffeine? Homework Equations The Attempt at a Solution column chromatography, distillation, Solid phase extraction and Tlc chromatography
  23. S

    Caffeine sublimation and melting point

    Why caffeine has 178 oC as point of sublimation but 237 oC as melting point? Is it about the pressure? If so, then what is the preesure that makes 237 as melting point instead of sublimation at 178 oC? Cuz the science websites always just said 237 is the melting point, but didn't mention the...
  24. A

    Calculate the pH of a solution made by dissolving 10.6 g caffeine

    1. Homework Statement Calculate the pH of a solution made by dissolving 10.6 g caffeine (C8H10N4O2, a weak base, Kb = 4.1 x 10-4) in enough water to make 100. mL of solution. Homework Equations pH = -log [H3O+] kb = kw/ka The Attempt at a Solution I first found conc.: MM=...
  25. U

    Medical Caffeine pills, are they a good idea?

    ...for the addicts among us? I remember back in the early nineties there were what was called "pick-ups", or caffeine pills supposedly used by students, in order to ingest a lot of caffeine. Do such pills still exist? Has anyone thought of adding caffeine to orange juice or any other...
  26. J

    Extract Caffeine from Coffee Easily & Safely

    I found this on the internet and was wondering if there was an easier way to extract the caffeine from coffee because this takes more time and equipment than i care to use is there any way i could do this at room pressure because last time i worked with pressurized stuff a seal broke and it shot...
  27. S

    Holy bad idea Batman Problems with caffeine

    Well to begin I should say that I used to be a caffeine freak. I averaged 2L of Diet Dr Pepper everyday for the past four years. About three weeks ago I ran out of pop and, being extremely busy with college, I was unable to get to the grocery store for anything other than a few bags of food...
  28. S

    Extraction/purification caffeine - help

    lo all, i´m having a small prob here -extract the caffein of the tea leaves with CH2Cl2 + NaOH - after the liquid-liquid extraction the organic phase (that contains the caffeine) was evaporated. then i joined some hot "toluen" (C6H5CH3) to the caffeine to occur a cristalization by slow...
  29. P

    Uncovering the Mystery of Acetanilide and Caffeine Melting Point Range

    I have a sample of 25 % acetanilide with 75 % caffeine. I record a melting point range of 198 - 240 degrees celcius acetanilide's melting point is 114.3 caffeine's melting point is 238 What would cause this huge experimental range? My thinking is that the acetanilide is...
  30. STAii

    What Are the Potential Long-Term Effects of High Caffeine Consumption?

    Hello. I was just at the super market, and i saw a drink which is supposed to give you "energy". It is called "Power Horse". Although it is very expensive (imported from Austria), i decided to buy it. Now, i don't really like the idea of drink that gives energy, therefore i suspected in its...