How Much Caffeine Is Too Much? Here's What Nutrition Experts Say

To some people, a cup of coffee or tea is a nice way to start the morning. To others, the caffeine from those beverages is a necessary crutch to get them through the day. Caffeine isn't bad for you when consumed in moderation, and there are several health benefits to caffeine, too.

So, how much caffeine can you have in a day before the positives turn into negatives? To figure out what exactly moderation means and what health benefits—and drawbacks—caffeine has to offer, we checked in with a dietitian and nutrition expert.

Recommended Amount of Caffeine

For most people, it's safe to consume up to 400 milligrams of caffeine per day. "According to the US National Library of Medicine, if you go over that amount, it can cause health problems such as insomnia, anxiety, nausea, headache, dizziness, restlessness or shakiness, and abnormal heart rhythm," nutrition expert Megan Meyer explains.

The FDA states that consuming about 1,200 milligrams of caffeine can potentially cause more serious side effects, like seizures. According to Meyer, this amount of caffeine can be found in dietary supplements that contain pure or highly concentrated caffeine in bulk quantities. "If you are using these types of products, it's imperative that you read the label and measure out a safe serving."

Meyer notes that moderate caffeine consumption in the range of 300 to 400 milligrams per day (mg/day) comes out to three cups of coffee, 5 ounces of espresso, seven cups of black tea, or 11 cups of green tea.

Here's how much caffeine is in a few of your favorite beverages:

What Health Benefits Does Caffeine Offer?

According to health experts, caffeine offers many benefits that can improve health. Here are a few:

Increases Alertness, Concentration, and Cognitive Function

According to Meyer, research shows that caffeine increases mental performance and alertness because it blocks a chemical in the brain that is associated with drowsiness. "Multiple studies have looked at the effects of caffeine on athletics and found that caffeine can prolong endurance and improve performance," she says.

Dietitian Amy Shapiro adds that caffeine can help "boost adrenaline, which can lead to increased physical performance." That being said, it's important to note that caffeine will not give you superhuman abilities or benefits but rather may help you perform tasks at your peak.

Can Reduce the Risk of Diabetes and Disease

Shapiro notes that some studies suggest that moderate consumption of caffeine may be associated with reduced risk of certain diseases such as Parkinson’s and Alzheimer’s. "Additionally, moderate caffeine consumption from coffee and tea may also lower the risk for chronic diseases like type 2 diabetes, heart disease, and some cancers. These beverages also contain polyphenols and antioxidants, which have been shown to protect against chronic diseases," Meyer adds.

Boosts Your Mood

There's a reason why so many coffee mugs come with phrases that allude to happiness post-coffee. "The effects of caffeine can enhance your mood by stimulating the release of dopamine and serotonin in the brain," says Shapiro. These hormones are responsible for happy, positive emotions.

Can Increase Metabolism

According to Shapiro, as a stimulant, caffeine can slightly increase metabolism. "It may even suppress appetite in some individuals," says Shapiro, noting that this is not a long-term effect and that people can eventually become tolerant to the increase caffeine has on fat-burning. "It's also important to keep in mind that there is wide variation in individual sensitivities to caffeine as well as how fast they metabolize it," adds Meyer.

Can Caffeine Be Harmful to Your Health?

Many side effects can come from consuming too much caffeine, especially if you have a caffeine sensitivity. Too much caffeine in the body can cause insomnia, jitters and anxiety, increased heart rate and blood pressure levels, digestive issues, dependency, and headaches. Similarly, too much caffeine can also be harmful, resulting in headaches, fatigue and/or drowsiness, decreased mental alertness, irritability, and mood changes.

Who Should Avoid Caffeine

Shapiro notes that certain groups of people should avoid or limit their caffeine consumption. "Pregnant women are often advised to limit their caffeine intake to no more than 200-300 milligrams per day, but this may vary based on the individual," says Shapiro, noting that those who breastfeed should also avoid caffeine as it may pass into their breast milk, which can affect nursing infants.

"Individuals who suffer from anxiety disorders, children and adolescents, and people with GI issues—as it can stimulate acid production in the stomach—and individuals taking certain medications such as some antibiotics or antidepressants should avoid or limit caffeine."

Does the Source of Caffeine Matter, Healthwise?

How does coffee stand up next to tea, energy drinks, and so on? According to an IFIC Food & Health Survey, many Americans are unsure if natural (plant-based) and synthetic sources of caffeine have a different effect on the body. In reality, studies have shown that the two types of caffeine are nearly indistinguishable, as they are both chemically identical.

Shapiro adds that many different sources contain varied amounts of caffeine and other compounds that may impact health. "For example, matcha contains caffeine but also L-Theanine, which helps to mellow out the adrenaline rush and eliminates jitters, allowing for a more even energy without anxiety," says Shapiro.

Tips to Lower Caffeine Intake

• Try half-caf. "Only a small amount (75-100 milligrams) is needed for an effect, so if you are having a 16-ounce cup of coffee, which has about 200 milligrams of caffeine, consider making it half-decaf," Meyer recommends. Also, reading food and beverage labels can help you watch your intake.
• Look out for secret sources of caffeine. Synonyms for caffeine include Guarana, Yoco, Yerba Mate, Guayusa, Yaupon Holly, Kola Nut, Cocoa, and Green Tea Extract—so keep an eye out for these ingredients as they count toward caffeine intake.
• Switch to decaf and caffeine-free options. If you like the taste that coffee and tea offer but don't want the caffeine, Shapiro suggests switching to caffeine-free options such as decaffeinated coffee and tea, which offer the familiar taste without the stimulating effects. "You can also explore caffeine-free alternatives such as herbal teas," Shapiro says.
• Plan activities or new rituals. Replace your usual coffee breaks with other activities that boost energy, such as taking a short walk or stepping outside. "Focus on improving your sleeping habits, which can reduce your reliance on caffeine for energy," says Shapiro.
• Keep a diary. If you want to truly cut back on caffeine, the best way to track your progress is to monitor your intake. "Gradually decrease consumption over several days or weeks to minimize symptoms of withdrawal," notes Shapiro.