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How Much Caffeine Is Too Much?

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Many people enjoy grabbing a cup of coffee as they’re out running errands or rely on their morning cup of joe to jump start their day.

Coffee does contain a known drug, however–caffeine, which is a stimulant. It’s important to monitor your caffeine intake throughout the day and be aware of how much coffee you’re consuming. But how do you know when the caffeine you’ve had is too much?

How Much Caffeine Is Too Much?

Caffeine helps you stay alert and boosts your concentration, but if you consume too much, this can lead to negative health consequences. According to the United States Food and Drug Administration (FDA), 400mg of caffeine is the limit per day for healthy adults. This is: 

  • About 4-5 cups of coffee 
  • Two energy drinks
  • 10 cans of soda 

If you consume more than 400mg of caffeine per day, this is definitely too much. Children also should not consume caffeine whatsoever, and even young adults need to be careful about their consumption. If you mix caffeine with other drugs such as alcohol, this can especially be dangerous. To play it safe, aim for a couple of cups of coffee each day, and no more than that.

How Do You Know How Much Caffeine A Food or Beverage Has?

If you need to find out how much caffeine you’re about to consume, luckily, it is easy to locate the information. Packaged foods typically include caffeine content on their nutrition labels, and if you can’t find it on the label, online databases list the amount of caffeine that popular foods and drinks contain. If you aren’t able to find the exact amount, you can at least typically receive a ballpark estimate so you can moderate your caffeine consumption.

Keep in mind that the amount of caffeine in your food and beverages varies widely depending on a range of factors. Your cup of coffee’s amount of caffeine is impacted by the roast, type of coffee bean, how it was prepared, if it is drip coffee versus espresso, and more. As a rule of thumb, however, an 8-ounce cup of coffee has about 80mg of caffeine, and a 12-ounce can of soda has about 40mg of caffeine.

9 Common Effects of Too Much Caffeine

Coffee, and other beverages that contain caffeine, can be very healthy for you when they’re consumed moderately.

Coffee can boost metabolism, physical performance, and your mood. However, too many cups of coffee can lead to an overload of caffeine, which in turn leads to negative and even dangerous side effects.

If you consume too much caffeine, you’ll know it, because your body and brain will react. The nine most common effects you may feel include:

  • Anxiety. Caffeine triggers adrenaline, which provides you with a boost of energy. Too much caffeine intensifies your adrenaline and causes nervousness and anxiety. One study found that men who consumed 300mg of caffeine said they experienced twice as much stress as those who took a placebo.

  • Insomnia. It’s well known that caffeine helps you stay awake. Due to this, you should refrain from consuming caffeine too close to your bedtime. Did you know that even your mid-afternoon coffee pick-me-up can interfere with your ability to fall asleep or achieve a good night’s sleep?

  • Digestive issues. Many people are familiar with coffee’s laxative effect. Caffeine itself stimulates bowel movement. However, since caffeine impacts digestive function, some people have found that consuming too much seriously interferes with their digestive system. 

  • Muscle breakdown. There is a serious condition called rhabdomyolysis, in which muscle fibers that are damaged end up entering the bloodstream. This leads to problems such as kidney failure. Although it’s rare, there have been instances of excessive caffeine intake leading to rhabdomyolysis. This has happened when someone consumed a high amount of caffeine in a short period of time. 

  • Addiction. Caffeine is indeed a drug, and many people end up forming habits surrounding their caffeine intake. When someone consumes a high amount of caffeine regularly, they may end up becoming physically or psychologically dependent on consuming caffeine to get through their day. 

  • High blood pressure. In several different studies, consuming caffeine has been shown to increase blood pressure. This is because caffeine stimulates the nervous system. When blood pressure is elevated, this increases the chances of suffering from a stroke or heart attack. 

  • Rapid heart rate. Your heart may beat faster due to caffeine’s stimulatory effects. In some people, caffeine can also lead to irregular heart rhythm, especially in cases of excessive consumption.

  • Fatigue. Even though coffee boosts your energy levels, you might find yourself crashing after the caffeine has left your system. Some people suffer from fatigue if they consume too much caffeine. 

  • Frequent urination and urgency. The stimulatory effects of caffeine impact your entire body, including your bladder. When you drink a lot of coffee, you’ll probably have to urinate frequently. This becomes a problem, however, when people develop incontinence and need to urinate frequently and urgently. It especially impacts elderly people who consume caffeine. 


Keep in mind that moderate use of caffeine will likely not lead to these side effects; many of these effects occur only when caffeine is consumed excessively. However, everyone has different sensitivity levels, and even a small amount of caffeine may have an adverse effect, so pay attention to how you feel as you drink your coffee throughout the day.

The Impact of Too Much Caffeine

Caffeine is a stimulant that’s consumed around the world in many different ways. As great as your morning cup of coffee is, it’s important to be aware that every time you consume caffeine, you are consuming a drug. Be mindful of how much you’re putting in your body.

The FDA recommends that healthy adults should not get more than 400mg of caffeine each day, and if you consume too much, you’ll likely know it due to the adverse physical effects that take place. If you find yourself crashing in the afternoon, getting jittery or anxious, or having digestive issues, lower your intake of caffeine to see if this makes a difference and speak to your doctor.

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