What to Know About Caffeine Use

Table of ContentsView AllTable of ContentsWhat Does Caffeine Do?Common Side EffectsSigns of UseCommon QuestionsTolerance, Dependence, & WithdrawalHow to Get Help

Table of ContentsView All

View All

Table of Contents

What Does Caffeine Do?

Common Side Effects

Signs of Use

Common Questions

Tolerance, Dependence, & Withdrawal

How to Get Help

Close

Caffeineis currently the world’s most commonly used drug.It is present in many foods and drinks, which makes it is easy to forget that it is a drug. It is even an ingredient in beverages and foods that are marketed to children. While caffeine has some health benefits, it does have significant negative effects on the body and brain.

Unlike many otherpsychoactive drugs, caffeine is legal and is one of the most widely used substances in the world.

Also Known As:Because caffeine is legal, slang terms are generally not used when referring to it. Slang terms for coffee and tea, two of the most common naturally caffeinated beverages, include Joe and cuppa.

Drug Class:Caffeine is classified as astimulant. It increases activity in the central nervous system.

Common Side Effects:Caffeine can increase energy levels and alertness, but side effects can include irritability, jitters,anxiety, rapid heart rate, and insomnia.

How to Recognize CaffeineCaffeine is an alkaloid found in a wide variety of plants including coffee beans, tea leaves, and cocoa beans. It is found both naturally and as an additive in many food and drink items including coffee, tea, chocolate, and soft drinks. On its own, caffeine has no flavor and does not have any nutritional value.

How to Recognize Caffeine

Caffeine is an alkaloid found in a wide variety of plants including coffee beans, tea leaves, and cocoa beans. It is found both naturally and as an additive in many food and drink items including coffee, tea, chocolate, and soft drinks. On its own, caffeine has no flavor and does not have any nutritional value.

Note that while Food and Drug Administration (FDA) regulations stipulate products containing added caffeine must be labeled, labeling is not required for food and beverages that naturally contain the stimulant. Since many products do not specify how much caffeine they contain, it can be difficult to know how much caffeine you are consuming.

What the Experts Say

Research has shown that caffeine can have both positive and negative effects on health.

It can improve mental performance—up to a point. In a study published in 2012, caffeine was shown to improve performance on a range of different tasks including vigilance, response times, information processing, and some—but not all—proofreading tasks.

But it’s no shortcut to improving your performance. When comparisons are made between people whose daily intake of caffeine is low (up to 100 mg caffeine per day) and those who regularly consume a lot of caffeine (more than 300 mg caffeine per day), the improvements are quite small and don’t get better with more caffeine.

Caffeine might improve reaction times, but expectations may also play a role. According to a review published in 2010, caffeine improves vigilance and reaction times.Another study published in 2009 explored the subtleties of how this works and found that at least some of the time, this is an expectancy effect.

Expectancy effects play a significant role in the effects that drugs have on people’s perceptions and behaviors. People’s expectancies of how caffeine will affect their performance—in particular, if they think it willimpairtheir performance—seems to underlie some of these improvements.

In other words, if people think consuming caffeine will make their performance worse, they try harder and compensate for the expected effects of caffeine.

At recommended doses, caffeine can have a beneficial effect on mood. Caffeine influences neurotransmitters that play a role in mood and mental performance including norepinephrine, dopamine, and acetylcholine. Research published in 2013 found that drinking two to three cups of caffeinated coffee each day was linked to a lower risk of suicide.

Recommendations

Off-Label Uses

Caffeine is sometimes prescribed or used off-label to improve mental alertness in patients experiencing fatigue or drowsiness. Caffeine citrate is also used as a short-term treatment for breathing problems in premature infants.

Caffeine can improve alertness, but it can also lead to a number of unpleasant side effects, including:

Caffeine can also affect:

Mood: While people often use caffeine to improve mood, excessive caffeine consumption can increase anxiety.

If you think your heartbeat is abnormal, check with your doctor.

Blood pressure: Caffeine consumption may raise blood pressure. This effect of caffeine, known as the “pressor effect,” is evident across age and gender groups, and is particularly pronounced in people with hypertension (high blood pressure). If you are unsure of whether this applies to you, ask your doctor about your blood pressure and get their advice on moderating your caffeine intake accordingly.

When caffeine is consumed in large quantities, theside effectscan range from unpleasant to severe, sometimes even resulting in caffeine overdose.

Caffeine can also pose dangers when taken with other substances including alcohol.Caffeine use can result in excessive alcohol consumption since the stimulant effects of caffeine mask the depressant effects of alcohol.

Since it is not an illicit drug, people rarely try to disguise their caffeine consumption. There are signs that someone might be overusing caffeine, including:

Caffeine overdose can lead to symptoms such as chest pain, confusion, hallucinations, convulsions, and trouble breathing. If someone is experiencing these symptoms, contact emergency services immediately.

Some people think caffeine improves their memory. According to a review published in 2015, the research evidence for this is mixed, although a number of studies found improved memory was associated with using energy drinks.

People also often wonder if excess caffeine consumption might contribute to heart problems. While caffeine use does have short-term effects on heart rate, it is unclear whether larger intakes increase the risk of cardiovascular problems in the longer term.

According to a 2017 review, several studies have indicated no increased risk for cardiovascular problems in either men or women related to caffeine intake, but caffeine may be problematic for people with high blood pressure.However, if you have any type of heart disease, you should speak with your doctor before consuming any caffeinated foods and beverages.

A common misconception is that caffeine use can cause infertility. A study published in 2017 suggests that there is no link between consuming low amounts of caffeine (around 200 mg per day or less) and fertility problems.

Another common question is whether caffeine pills and other high-dose products are different from food and beverages containing caffeine. Products that contain high concentrations of caffeine such as pills and powders, while not chemically different from other forms of the stimulant, do pose additional dangers.

Because these products are so concentrated, the difference between a safe and toxic dose is difficult to measure, which increases the risk of accidental overdose and negative side effects such as seizures.

Tolerance, Dependence, and Withdrawal

Repeated consumption of caffeine can lead to tolerance, dependence, and withdrawal. Tolerance takes place when you must consume larger or more frequent doses in order to have the same effects. Dependence involves needing to keep taking the substance in order to ward off unpleasantwithdrawaleffects.

How Long Does Caffeine Stay in Your System?

Caffeine reaches peak levels in the body about an hour after consumption, but you may continue to feel these stimulating effects for up to six hours.

Addiction

While using caffeine can lead to becoming physically or psychologically dependent on it, it does not have strong enough of an effect on the brain’s reward system to result in a trueaddiction. The National Institute on Drug Abuse (NIDA) defines addiction as the chronic, uncontrollable use of a substance despite negative consequences.

However, people often casually refer to their love of coffee and other caffeine-containing beverages as an “addiction.”

Caffeine Intoxication

Caffeine Addiction Symptoms and Withdrawal

Withdrawal

People often continue to use caffeine as a way to reduce any negative symptoms of caffeine withdrawal that they might experience.

Caffeine withdrawal usually begins within 12 to 24 hours after consuming the last dose. It can lead to a number of unpleasant withdrawal effects including:

Withdrawal symptoms can range from mild to more severe depending on how much caffeine you are used to consuming. These unpleasant effects usually begin to subside within two or three days.

Caffeine Withdrawal Symptoms

If you use a lot of caffeine—drinking the equivalent of more than three cups of tea or coffee per day—it may be negatively affecting your health, so lowering your intake is worth considering.

The best approach is to gradually taper your caffeine consumption. Doing this lowers your dependence gradually while minimizing the negative effects of withdrawal.

Talk to your doctor if you are concerned about your caffeine use, or contact SAMSHA at 1-800-662-4357 to find mental health services in your area.

16 SourcesVerywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Meredith SE, Juliano LM, Hughes JR, Griffiths RR.Caffeine use disorder: A comprehensive review and research agenda.J Caffeine Res. 2013;3(3):114-130. doi:10.1089/jcr.2013.0016Richards G, Smith AP.A review of energy drinks and mental health, with a focus on stress, anxiety, and depression.J Caffeine Res. 2016;6(2):49-63. doi:10.1089/jcr.2015.0033Brunyé TT, Mahoney CR, Rapp DN, Ditman T, Taylor HA.Caffeine enhances real-world language processing: Evidence from a proofreading task.J Exp Psychol Appl.2012;18(1):95-108. doi:10.1037/a0025851Koppelstaetter F, Poeppel TD, Siedentopf CM, et al.Caffeine and cognition in functional magnetic resonance imaging.J Alzheimers Dis. 2010;20 Suppl 1:S71-84. doi:10.3233/JAD-2010-1417Harrell PT, Juliano LM.Caffeine expectancies influence the subjective and behavioral effects of caffeine.Psychopharmacology (Berl). 2009;207(2):335-42. doi:10.1007/s00213-009-1658-5Lucas M, O’reilly EJ, Pan A, et al.Coffee, caffeine, and risk of completed suicide: results from three prospective cohorts of American adults.World J Biol Psychiatry.2014;15(5):377-86. doi:10.3109/15622975.2013.795243Fitness C on N and the C on SM and.Sports drinks and energy drinks for children and adolescents: Are they appropriate?Pediatrics. 2011;127(6):1182-1189. doi:10.1542/peds.2011-0965American College of Obstetricians and Gynecologists. Committee Opinion.Moderate caffeine consumption during pregnancy. 2010. Reaffirmed 2020.Abdel-Hady H, Nasef N, Shabaan AE, Nour I.Caffeine therapy in preterm infants.World J Clin Pediatr. 2015;4(4):81-93. doi:10.5409/wjcp.v4.i4.81American Psychiatric Association.Diagnostic and Statistical Manual of Mental Disorders.5th edition. Washington DC; 2013.Turnbull D, Rodricks JV, Mariano GF, Chowdhury F.Caffeine and cardiovascular health.Regul Toxicol Pharmacol.2017;89:165-185. doi:10.1016/j.yrtph.2017.07.025Centers for Disease Control and Prevention.Alcohol and caffeine.Alsunni AA.Energy drink consumption: Beneficial and adverse health effects.Int J Health Sci (Qassim). 2015;9(4):468-474.Lyngsø J, Ramlau-Hansen CH, Bay B, Ingerslev HJ, Hulman A, Kesmodel US.Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis.Clin Epidemiol. 2017;9:699-719. doi:10.2147/CLEP.S146496Food and Drug Administration.Pure and highly concentrated caffeine.National Institute on Drug Abuse.Drugs, brains, and behavior: The science of addiction.

16 Sources

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Meredith SE, Juliano LM, Hughes JR, Griffiths RR.Caffeine use disorder: A comprehensive review and research agenda.J Caffeine Res. 2013;3(3):114-130. doi:10.1089/jcr.2013.0016Richards G, Smith AP.A review of energy drinks and mental health, with a focus on stress, anxiety, and depression.J Caffeine Res. 2016;6(2):49-63. doi:10.1089/jcr.2015.0033Brunyé TT, Mahoney CR, Rapp DN, Ditman T, Taylor HA.Caffeine enhances real-world language processing: Evidence from a proofreading task.J Exp Psychol Appl.2012;18(1):95-108. doi:10.1037/a0025851Koppelstaetter F, Poeppel TD, Siedentopf CM, et al.Caffeine and cognition in functional magnetic resonance imaging.J Alzheimers Dis. 2010;20 Suppl 1:S71-84. doi:10.3233/JAD-2010-1417Harrell PT, Juliano LM.Caffeine expectancies influence the subjective and behavioral effects of caffeine.Psychopharmacology (Berl). 2009;207(2):335-42. doi:10.1007/s00213-009-1658-5Lucas M, O’reilly EJ, Pan A, et al.Coffee, caffeine, and risk of completed suicide: results from three prospective cohorts of American adults.World J Biol Psychiatry.2014;15(5):377-86. doi:10.3109/15622975.2013.795243Fitness C on N and the C on SM and.Sports drinks and energy drinks for children and adolescents: Are they appropriate?Pediatrics. 2011;127(6):1182-1189. doi:10.1542/peds.2011-0965American College of Obstetricians and Gynecologists. Committee Opinion.Moderate caffeine consumption during pregnancy. 2010. Reaffirmed 2020.Abdel-Hady H, Nasef N, Shabaan AE, Nour I.Caffeine therapy in preterm infants.World J Clin Pediatr. 2015;4(4):81-93. doi:10.5409/wjcp.v4.i4.81American Psychiatric Association.Diagnostic and Statistical Manual of Mental Disorders.5th edition. Washington DC; 2013.Turnbull D, Rodricks JV, Mariano GF, Chowdhury F.Caffeine and cardiovascular health.Regul Toxicol Pharmacol.2017;89:165-185. doi:10.1016/j.yrtph.2017.07.025Centers for Disease Control and Prevention.Alcohol and caffeine.Alsunni AA.Energy drink consumption: Beneficial and adverse health effects.Int J Health Sci (Qassim). 2015;9(4):468-474.Lyngsø J, Ramlau-Hansen CH, Bay B, Ingerslev HJ, Hulman A, Kesmodel US.Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis.Clin Epidemiol. 2017;9:699-719. doi:10.2147/CLEP.S146496Food and Drug Administration.Pure and highly concentrated caffeine.National Institute on Drug Abuse.Drugs, brains, and behavior: The science of addiction.

Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Meredith SE, Juliano LM, Hughes JR, Griffiths RR.Caffeine use disorder: A comprehensive review and research agenda.J Caffeine Res. 2013;3(3):114-130. doi:10.1089/jcr.2013.0016Richards G, Smith AP.A review of energy drinks and mental health, with a focus on stress, anxiety, and depression.J Caffeine Res. 2016;6(2):49-63. doi:10.1089/jcr.2015.0033Brunyé TT, Mahoney CR, Rapp DN, Ditman T, Taylor HA.Caffeine enhances real-world language processing: Evidence from a proofreading task.J Exp Psychol Appl.2012;18(1):95-108. doi:10.1037/a0025851Koppelstaetter F, Poeppel TD, Siedentopf CM, et al.Caffeine and cognition in functional magnetic resonance imaging.J Alzheimers Dis. 2010;20 Suppl 1:S71-84. doi:10.3233/JAD-2010-1417Harrell PT, Juliano LM.Caffeine expectancies influence the subjective and behavioral effects of caffeine.Psychopharmacology (Berl). 2009;207(2):335-42. doi:10.1007/s00213-009-1658-5Lucas M, O’reilly EJ, Pan A, et al.Coffee, caffeine, and risk of completed suicide: results from three prospective cohorts of American adults.World J Biol Psychiatry.2014;15(5):377-86. doi:10.3109/15622975.2013.795243Fitness C on N and the C on SM and.Sports drinks and energy drinks for children and adolescents: Are they appropriate?Pediatrics. 2011;127(6):1182-1189. doi:10.1542/peds.2011-0965American College of Obstetricians and Gynecologists. Committee Opinion.Moderate caffeine consumption during pregnancy. 2010. Reaffirmed 2020.Abdel-Hady H, Nasef N, Shabaan AE, Nour I.Caffeine therapy in preterm infants.World J Clin Pediatr. 2015;4(4):81-93. doi:10.5409/wjcp.v4.i4.81American Psychiatric Association.Diagnostic and Statistical Manual of Mental Disorders.5th edition. Washington DC; 2013.Turnbull D, Rodricks JV, Mariano GF, Chowdhury F.Caffeine and cardiovascular health.Regul Toxicol Pharmacol.2017;89:165-185. doi:10.1016/j.yrtph.2017.07.025Centers for Disease Control and Prevention.Alcohol and caffeine.Alsunni AA.Energy drink consumption: Beneficial and adverse health effects.Int J Health Sci (Qassim). 2015;9(4):468-474.Lyngsø J, Ramlau-Hansen CH, Bay B, Ingerslev HJ, Hulman A, Kesmodel US.Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis.Clin Epidemiol. 2017;9:699-719. doi:10.2147/CLEP.S146496Food and Drug Administration.Pure and highly concentrated caffeine.National Institute on Drug Abuse.Drugs, brains, and behavior: The science of addiction.

Meredith SE, Juliano LM, Hughes JR, Griffiths RR.Caffeine use disorder: A comprehensive review and research agenda.J Caffeine Res. 2013;3(3):114-130. doi:10.1089/jcr.2013.0016

Richards G, Smith AP.A review of energy drinks and mental health, with a focus on stress, anxiety, and depression.J Caffeine Res. 2016;6(2):49-63. doi:10.1089/jcr.2015.0033

Brunyé TT, Mahoney CR, Rapp DN, Ditman T, Taylor HA.Caffeine enhances real-world language processing: Evidence from a proofreading task.J Exp Psychol Appl.2012;18(1):95-108. doi:10.1037/a0025851

Koppelstaetter F, Poeppel TD, Siedentopf CM, et al.Caffeine and cognition in functional magnetic resonance imaging.J Alzheimers Dis. 2010;20 Suppl 1:S71-84. doi:10.3233/JAD-2010-1417

Harrell PT, Juliano LM.Caffeine expectancies influence the subjective and behavioral effects of caffeine.Psychopharmacology (Berl). 2009;207(2):335-42. doi:10.1007/s00213-009-1658-5

Lucas M, O’reilly EJ, Pan A, et al.Coffee, caffeine, and risk of completed suicide: results from three prospective cohorts of American adults.World J Biol Psychiatry.2014;15(5):377-86. doi:10.3109/15622975.2013.795243

Fitness C on N and the C on SM and.Sports drinks and energy drinks for children and adolescents: Are they appropriate?Pediatrics. 2011;127(6):1182-1189. doi:10.1542/peds.2011-0965

American College of Obstetricians and Gynecologists. Committee Opinion.Moderate caffeine consumption during pregnancy. 2010. Reaffirmed 2020.

Abdel-Hady H, Nasef N, Shabaan AE, Nour I.Caffeine therapy in preterm infants.World J Clin Pediatr. 2015;4(4):81-93. doi:10.5409/wjcp.v4.i4.81

American Psychiatric Association.Diagnostic and Statistical Manual of Mental Disorders.5th edition. Washington DC; 2013.

Turnbull D, Rodricks JV, Mariano GF, Chowdhury F.Caffeine and cardiovascular health.Regul Toxicol Pharmacol.2017;89:165-185. doi:10.1016/j.yrtph.2017.07.025

Centers for Disease Control and Prevention.Alcohol and caffeine.

Alsunni AA.Energy drink consumption: Beneficial and adverse health effects.Int J Health Sci (Qassim). 2015;9(4):468-474.

Lyngsø J, Ramlau-Hansen CH, Bay B, Ingerslev HJ, Hulman A, Kesmodel US.Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis.Clin Epidemiol. 2017;9:699-719. doi:10.2147/CLEP.S146496

Food and Drug Administration.Pure and highly concentrated caffeine.

National Institute on Drug Abuse.Drugs, brains, and behavior: The science of addiction.

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