How Much Caffeine Is Too Much?

Coffee

Verywell / Alexandra Shytsman

If you enjoy a cup of coffee or tea you have likely experienced the jitters at some point. Drinking too much caffeine may cause side effects, some of which can be harmful to your health. Some people who are especially sensitive to caffeine may experience unpleasant reactions from consuming just a small amount.

Regardless of your level of tolerance and dependence, side effects from drinking too much caffeine include anxiety, nervousness, insomnia, heart palpitations, muscle spasms, upset stomach, and more. Learn how much caffeine is too much and why it can be difficult to cut back on your consumption, plus tips for reducing your intake.

People with underlying medical conditions could be more susceptible to the negative side effects of caffeine such as heart palpitations.

How Much Caffeine Is Too Much?

The U.S. Food and Drug Administration (FDA) states that a safe amount of caffeine for healthy adults is about 400 milligrams per day without negative side effects. That's about four or five 8-ounce cups (not giant mugs) of brewed coffee; five shots of espresso; or two energy drinks.

Most adults don't experience the effects of caffeine intoxication when drinking less than 250 milligrams of caffeine (about 2.5 cups of coffee) per day. You are more likely to experience negative side effects if you exceed the recommended amount of 400 milligrams.

Coffee and tea are associated with a host of health benefits, including the prevention of certain cancers, diabetes, and heart disease. Caffeine improves cognitive function, enhance athletic ability and boost energy during workouts, and can even help turn around a bad mood.

Caffeine is a stimulant, and some studies show an association between small doses of caffeine and improved response time and exercise performance. Caffeine can be used to enhance a variety of mental and physical tasks by heightening productivity and increasing concentration and accuracy. In addition, research shows a strong association between caffeine intake and weight loss.

But caffeine can also cause negative side effects depending on the dose. That's why it's important to monitor your intake and be aware of the different foods and beverages containing caffeine. In addition to coffee and tea, caffeine is also found in soda and energy drinks, foods and dietary supplements containing energy-boosting ingredients, chocolate, some chewing gums, and even candies. Some over-the-counter pain relievers like Excedrin also contain caffeine.

You can avoid accidental overconsumption of caffeine as long as you stay within the recommended limit of 400 milligrams per day. Health experts say that consuming more than 600 milligrams is too much. According to the FDA, the dangerous toxic effects of a caffeine overdose can be experienced at 1,200 milligrams in a day. To that end, the FDA issued a warning to avoid certain dietary supplements containing highly concentrated amounts of caffeine.

Beware of caffeine pills and powders that promise to deliver a jolt quickly and effectively—they do exactly that. These products can deliver large doses of caffeine in a very short amount of time and could lead to overconsumption.

Symptoms of Too Much Caffeine

Although caffeine can act as a diuretic, it is no longer believed to cause dehydration. Research shows that your body adjusts to your caffeine intake, which means that drinking caffeinated beverages is not likely to increase your need for water.

The stimulant properties of caffeine increase your blood pressure and heart rate. Consuming too much may give you that jumpy and slightly alarmed feeling known as the jitters. Larger amounts of caffeine may make you irritable, sleepless, and possibly trigger anxiety, cause diarrhea, and prevent the absorption of calcium in your body. Other side effects include:

  • Nervousness
  • Frequent urination
  • Headaches
  • Heartburn and indigestion
  • Heart palpitations or fast heartbeat
  • Incontinence
  • Muscle spasms
  • Upset stomach

In rare cases, a condition known as rhabdomyolysis can occur with the overconsumption of caffeine. This breakdown of muscle tissue occurs when protein from damaged muscle fibers enter the bloodstream, which may cause kidney damage if left untreated.

Signs of Too Much Caffeine in Children

The FDA has not set a limit for caffeine intake among children but states that the American Academy of Pediatrics (AAP) discourages the consumption of caffeine by both children and adolescents.

According to the American Academy of Child and Adolescent Psychiatry (AACAP), children under 12 should not consume any caffeine and avoid common sources of the stimulant found in food and beverages including soda and chocolate. For adolescents 12–18 years old, the AACAP suggest limiting caffeine to no more than 100 milligrams (about two 12-ounce cans of soda) per day. Additionally, both the AACAP and AAP recommend that children and adolescents avoid energy drinks entirely.

Since caffeine affects the central nervous system as a stimulant and children's brains are more sensitive to caffeine than adults, it may cause the following health issues:

  • Anxiety
  • Hyperactivity
  • Poor sleep patterns
  • Unhealthy growth patterns

Caffeine Addiction

In addition to the negative short-term effects of too much caffeine, it's possible to develop a dependency on regular consumption, which means you will experience mild withdrawal symptoms. Symptoms of withdrawal begin at 12–24 hours after the last dose of caffeine and can last from two to nine days. These symptoms include:

  • Fatigue
  • Headaches
  • Sleeplessness
  • Irritability
  • Nausea
  • Difficulty concentrating
  • Muscle aches
  • A feeling of being "addicted"

Keep in mind that caffeine dependency is not the same as drug addiction. Though caffeine does not cause "addiction" in the traditional sense, you may begin to crave the rise in dopamine that's associated with caffeine consumption. While too much caffeine may be harmful, it is unlikely to result in the same negative consequences as drug addiction.

Safe Caffeine Consumption

Precautions

If you're wondering whether you should curb your caffeine intake, if you're feeling jittery, anxious, or having trouble sleeping it might be a good idea to cut back. While children under 12 should avoid caffeine and adolescents should limit their consumption, other groups should be cautious as well.

Those with medical conditions including heart problems or nervous system disorders should limit their consumption. Caffeine can also affect the absorption of certain medications and may lead to dangerous drug interactions.

Additionally, pregnant or breastfeeding women should decrease their caffeine intake. Consuming more than 200 milligrams of caffeine per day (about 12 ounces of coffee) has been associated with:

  • Poor fetal growth
  • Reduced milk supply for breastfeeding
  • Slightly increased risk of miscarriage

Speak to your healthcare provider to determine whether your caffeine intake is within a healthy range based on your individual circumstances.

Interactions

There are 54 known drug interactions ranging from mild to severe that can occur with caffeine, including prescription and over-the-counter medications and dietary supplements. Some drug interactions may enhance the negative side effects associated with caffeine consumption such as heart palpitations and insomnia. The most common moderate interactions include:

  • Adderall
  • Benadryl
  • Echinacea
  • Ephedrine
  • Fish Oil
  • Theophylline
  • Tylenol
  • Vitamin B12
  • Vitamin C
  • Vitamin D3
  • Xanax
  • Zyrtec

In addition, health experts warn about combining caffeine or energy drinks with alcohol. According to the Centers for Disease Control and Prevention (CDC), "When alcohol is mixed with caffeine, the caffeine can mask the depressant effects of alcohol, making drinkers feel more alert than they would otherwise. As a result, they may drink more alcohol and become more impaired than they realize, increasing the risk of alcohol-attributable harms."

Research describes a caffeine and alcohol interaction as a "perfect storm" and shows the potentially dangerous side effects of combining a stimulant with a depressant. Caffeine can block the withdrawal effects of alcohol, leaving a person to feel less impaired than they actually are.

Caffeine Overdose

The unpleasant side effects of too much caffeine will usually resolve on their own. If you notice an irregular heartbeat accompanied by feeling dizzy or faint, it may be time to call your doctor or go to the emergency room. After too much caffeine, most people will feel better within four to six hours. While you wait:

  • Avoid additional sources of caffeine, including chocolate.
  • Drink lots of water and replace your electrolytes, especially if you've been having diarrhea or stomach issues.
  • Try deep breathing, or go for walk to burn excess energy and lower anxiety levels from caffeine.

Irregular heartbeats can cause a heart attack, especially for someone with a pre-existing heart condition. Seizure disorders can also be triggered by caffeine.

Tips for Reducing Caffeine Intake

Kicking the caffeine habit cold turkey isn't recommended as it can lead to symptoms of caffeine withdrawal, which will eventually pass. Blending regular caffeinated beverages with decaf versions can help to ease symptoms. It's recommended that you take a few weeks to gradually reduce your caffeine intake and dependency. Try these tips to start cutting back on your consumption:

  • Swap coffee with tea
  • Switch to decaf
  • Alternate between decaf and regular
  • Quit caffeinated soda and energy drinks
  • Try yerba mate or chicory root
  • Keep a log of daily consumption

A Word From Verywell

The taste and aroma of a good cup of Joe is a cherished morning ritual for many. Indeed, many people believe they can't function without their first cup (or two) of coffee in the morning. Others may drink coffee or caffeinated beverages throughout the day for a jolt of energy to beat the afternoon slump.

Fortunately, a safe amount of caffeine doesn’t usually pose a health risk to the average person, but if you have a health condition or are prone to reactions you might want to cut back your intake. If a boost of energy is all you really need, try eating more energy-dense foods or switching to coffee alternatives.

If you're trying to avoid caffeine altogether, remember to gradually reduce your consumption instead of quitting all at once to avoid unpleasant withdrawal symptoms. Whether your goal is to simply consume less caffeine or be completely caffeine-free, you may notice that you naturally have more sustaining energy once you are less dependent on it.

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  1. U.S. Food & Drug Administration. Spilling the Beans: How Much Caffeine is Too Much?. Updated December 12, 2018.

  2. Temple JL, Bernard C, Lipshultz SE, Czachor JD, Westphal JA, Mestre MA. The safety of ingested caffeine: A comprehensive review. Front Psychiatry. 2017;8:80. doi:10.3389/fpsyt.2017.00080

  3. Higashi Y. Coffee and endothelial function: A coffee paradox? Nutrients. 2019;11(9). doi: 10.3390/nu11092104

  4. Zaragoza J, Tinsley G, Urbina S, et al. Effects of acute caffeine, theanine and tyrosine supplementation on mental and physical performance in athletes. J Int Soc Sports Nutr. 2019;16(1):56. doi:10.1186/s12970-019-0326-3

  5. Temple JL, Bernard C, Lipshultz SE, Czachor JD, Westphal JA, Mestre MA. The safety of ingested caffeine: A comprehensive review. Front Psychiatry. 2017;8:80. doi:10.3389/fpsyt.2017.00080

  6. Tabrizi R, Saneei P, Lankarani KB, et al. The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trialsCrit Rev Food Sci Nutr. 2019;59(16):2688-2696. doi:10.1080/10408398.2018.1507996

  7. Cleveland Clinic. Caffeine: How to Hack It and How to Quit It. Updated December 23, 2020.

  8. U.S. Food & Drug Administration. Pure and Highly Concentrated Caffeine. Updated September 21, 2018.

  9. Killer SC. Blannin AK, Jeukendrup AE. No Evidence of Dehydration with Moderate Daily Coffee Intake: A Counterbalanced Cross-Over Study in a Free-Living Population. PLOS One. 2014;9(1):e84154. doi:10.1371/journal.pone.0084154

  10. U.S. National Library of Medicine. MedlinePlus. Caffeine. Updated October 6, 2020.

  11. Chiang W-F, Liao M-T, Cheng C-J, Lin S-H. Rhabdomyolysis induced by excessive coffee drinkingHum Exp Toxicol. 2014;33(8):878-881. doi:10.1177/0960327113510536

  12. American Academy of Child & Adolescent Psychiatry. Caffeine and Children. July 2020.

  13. Seifert SM, Schaechter JL, Hershorin ER, Lipshultz SE. Pediatrics. 2011;127(3):511-528 doi:10.1542/peds.2009-3592

  14. Kids Health from Nemours. Caffeine. Updated 2017.

  15. National Institute on Drug Abuse for Teens. Is caffeine really addictive? Updated 2020.

  16. National Institute on Drug Abuse. Is Caffeine Really Addictive? May 10, 2016.

  17. The American College of Obstetrics and Gynecology. Moderate caffeine consumption during pregnancy. Updated 2016.

  18. Drugs.com. Caffeine Drug Interactions.

  19. Temple JL, Bernard C, Lipshultz SE, Czachor JD, Westphal JA, Mestre MA. The safety of ingested caffeine: a comprehensive reviewFront Psychiatry. 2017;8:80. doi:10.3389/fpsyt.2017.00080

  20. Centers for Disease Control and Prevention. Alcohol and Caffeine. February 4, 2020.

  21. Ferré S, O’Brien MC. Alcohol and caffeine: the perfect stormJ Caffeine Res. 2011;1(3):153-162. doi:10.1089/jcr.2011.0017

  22. van Koert RR, Bauer PR, Schuitema I, Sander JW, Visser GH. Caffeine and seizures: A systematic review and quantitative analysis. Epilepsy Behav. 2018;80:37-47. doi:10.1016/j.yebeh.2017.11.003

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