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How Much Caffeine Is Too Much?

Does sipping your favorite morning latte make you feel a bit jittery? Perhaps you occasionally enjoy a cup of coffee with your dessert, then find yourself tossing and turning at night. This begs the question, “how much caffeine is too much?”

Caffeine is a natural substance derived from plants, which is commonly found in tea, coffee, and chocolate. In South America, popular alternative teas like yerba mate and Ilex guayusa have caffeine as well. It’s sometimes used as a flavoring (e.g., the Brazilian shrub known as guarana). Lastly, many products, including ice creams, desserts, and PMS relievers, add caffeine as an ingredient. But the question of whether caffeine is good or bad for you is a complex one. 

The FDA reports that the toxic and negative effects of caffeine, including seizures, start with rapid consumption of 1200 milligrams (0.15 tablespoons) or more. Some dietary supplements currently on the market contain high concentrations of pure caffeine. They’re particularly dangerous and have resulted in at least two recent deaths in the U.S.

Note, however, that not all caffeine side effects are adverse. Small doses, ranging from 150 to 650 milligrams, have been shown to improve both physical endurance and cognitive performance. This is what’s referred to as a caffeine high. The optimal dosage of caffeine for enhanced physical performance falls between 200 and 600 milligrams. 

Furthermore, multiple studies uncovered a link between caffeine and cognitive performance. Subjects were given either a placebo or between 200 and 400 milligrams of caffeine. Then, their human electroencephalogram (EEG) patterns (while at rest and during mental tests) were monitored. Results indicated that 200 milligrams of caffeine fostered better concentration. In addition to helping participants finish their tests faster, the number of problems solved correctly per minute increased. EEG spectral density tests confirmed these findings. 

Determining how much caffeine per day is right for you depends largely on your history with caffeine consumption. Much like alcohol, you can build up a tolerance to caffeine. Those who don’t drink it regularly are more sensitive to coffee side effects. Other contributing factors include age, body mass, medications, health conditions, genetics, and anxiety-related issues. 

FDA recommendations advise healthy adults to limit their caffeine intake to 400 milligrams a day. This is equivalent to approximately four to five cups of coffee, 10 cans of cola, or two energy shots.

Just remember, not all coffee is created equal. Caffeine content varies significantly between brands, so be sure to read the label. It’s also based on the origin of the beans, processing methods, and preparation.

More than 400 milligrams per day is considered heavy usage and may produce potentially dangerous side effects. Caffeine is a stimulant that can prevent sleep. Your particular tipping point is based on how quickly you metabolize caffeine, as well as:

  • The time of day you consume it
  • Your usual caffeine intake
  • Whether you’re tired or well-rested
  • Whether you smoke or use oral contraceptives

Women who are pregnant, breastfeeding, or trying to conceive should limit their caffeine intake and consult a doctor regarding health consequences. 

Steer clear of dietary supplements comprised of highly-concentrated or pure caffeine. They come in powdered or liquid forms and bulk packaging. Consumers end up measuring their own servings, which is potentially toxic or even lethal. 

As the levels of pure caffeine rise, so do the chances of experiencing serious side effects. For example, one teaspoon of pure caffeine in powdered form is roughly equal to 28 cups of coffee. In these quantities, caffeine consumption is toxic and can have serious health consequences. 

Although everyone presents symptoms of having too much caffeine differently, overconsumption generally causes:

  • Insomnia or restlessness
  • Jitters or shaky hands
  • Anxiousness
  • Rapid heart rate
  • Upset stomach
  • Nausea
  • Headache
  • Dysphoria (i.e., a feeling of unhappiness)

Keep an eye out for negative side effects of caffeine, including:

Caffeine is a stimulant that’s not appropriate for everyone. Specific factors and conditions make some individuals especially sensitive to it. Medications that we currently know should not be combined with caffeine include ephedrine, theophylline, and echinacea. There may be additional drugs that don’t mix well with caffeine in your particular case.  

Patients with anxiety-related disorders should avoid caffeine, which could aggravate their condition. If you’re pregnant, breastfeeding, or trying to conceive, think about eliminating caffeine altogether. Switch to decaf or caffeine-free beverages. (Note that decaf doesn’t necessarily mean caffeine-free.) To be safe, consult your doctor about what’s right for you.

Individuals with heart conditions might want to keep a close watch on caffeine consumption as well. However, medical experts haven’t completely agreed on the need for this. 

Lastly, while there’s no minimum age requirement, the American Academy of Pediatrics does not recommend caffeine for children or adolescents.

Like most things, caffeine has both positive and negative aspects, and moderation is key. If you’re noticing negative side effects of caffeine, gradually cut back. Quitting cold turkey can trigger withdrawal symptoms in some, such as headaches and irritability. Instead, attempt to wean yourself slowly with decaf or herbal teas. 

So how much caffeine is too much? The answer is slightly different for everyone. Remain aware of how your body responds to caffeine. Seek advice from your doctor if you think caffeine is starting to take a toll on your health.




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