When does your coffee habit start to cross the line from productive and enjoyable to risky and unhealthy?
a clock face made out of cups of coffee
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Caffeine is a natural stimulant well-known for its health benefits, from boosting your mood to reducing your risk of type 2 diabetes. However, having too much can be harmful to your body.

Everyone widely consumes caffeine, whether it's in coffee, tea or energy drinks. According to the National Health and Nutrition Examination Survey, approximately 90% of the U.S. population relies on caffeine's stimulant effect to get them moving physically and mentally each morning. This isn't necessarily a "bad" or unhealthy habit, assuming those caffeinated beverages aren't loaded with added sugars. In fact, research suggests that moderate caffeine consumption improves alertness, cognitive performance and mood and even helps you live longer.

But at what point does caffeine intake can be unhealthy? What are the signs and symptoms of too much caffeine? And how much is too much in a day?

How Much Caffeine Is Safe

In general, the 2020-2025 Dietary Guidelines for Americans advise that up to 400 milligrams of caffeine—around four to five cups of coffee—each day can be part of a healthy diet. The FDA also cited this dosage as causing no adverse effects in most adults.

However, some people could be more sensitive to caffeine's stimulant effects. If you take certain medications, such as antidepressants and anticoagulants, you should talk to your health care team to learn how much caffeine is safe for you. Also, people who are pregnant, breastfeeding or becoming pregnant should consume no more than 200 milligrams of caffeine per day, per the National Institutes of Health.

There are no U.S. official guidelines on how much caffeine is safe for kids and teenagers. Yet, according to the Government of Canada, children and teenagers should not consume more than 2.5 milligrams per kg of their body weight.

Symptoms of Too Much Caffeine

Consuming slightly more than 400 milligrams of coffee increases the risk of side effects, such as:

  • Nervousness
  • Jitters
  • Heart racing
  • Nausea
  • Headaches
  • Frequent urination
  • Increased thirst
  • Not being able to fall asleep
  • Irregular heartbeat
  • Chest pain

Even with this upper limit, it's important to be aware that caffeine affects each person differently. The body's metabolism and management of caffeine are influenced by age, health status, medications, smoking and even certain genetic variants, per a 2018 publication in Pharmacological Reviews. The body also slowly builds a tolerance when caffeine is regularly consumed. This means people who rarely consume caffeine (or consume it in minimal amounts) may be more apt to experience some of the milder symptoms above when they consume 200 to 300 mg compared to someone who regularly consumes that amount.

How do you keep caffeine on the safe side that boosts mental focus?

Keeping tabs on your caffeine intake is your best bet, and this involves becoming familiar with the amount of caffeine in its primary sources.

Caffeine in Drinks and Foods

Caffeine is found in many popular beverages and foods, such as coffee, tea, soft drinks and chocolate.

Most people's caffeine consumption comes from coffee, tea and sodas. Chocolate and coffee-inspired desserts contribute a small amount. Other contributors are energy drinks and other products (like caffeinated gum) which contain added caffeine. These products can quickly push intake above 400 mg and are often associated with those greater health threats.

Check out these common caffeine sources. Make sure to note the serving size and adjust the caffeine amount accordingly. Caffeine amounts come from the USDA's FoodData Central.

Coffee, coffee drinks, teas and sodas

  • Coffee, brewed (8 oz): 92 to 110 mg
  • Coffee, instant (8 oz): 63 mg
  • Decaf coffee (8 oz): 2 mg
  • Expresso (2 oz): 127 mg
  • Hot or iced latte (8 oz): 88 mg
  • Cappuccino (8 oz): 86 mg
  • Green tea, iced or hot (8 oz): 8 to 29 mg
  • Black tea, iced or hot (8 oz): 48 mg
  • Oolong tea, hot (8 oz): 38 mg
  • Herbal teas, hot (8 oz): 0 mg
  • Cola (12 oz can): 42 mg
  • Diet cola (12 oz can): 43 mg
  • Fruit-flavored soda (12 oz can): 54 mg

Caffeine amounts in coffee can vary depending on bean type, brewing method, roasting and strength or concentration, per a 2021 article in Foods. They will also vary slightly by brand for tea and soda.

Chocolate and other foods and beverages with naturally occurring caffeine

  • Dark chocolate (1 oz, 60-80% cacao): 22 to 24 mg
  • Milk chocolate (1 oz): 9 to 15 mg
  • Semi-sweet chocolate chips (1/4 cup): 25 to 28 mg
  • Unsweetened cocoa powder (2 Tbsp): 8 mg
  • Hot cocoa (8 oz, mix or homemade): 5 to 8 mg
  • Tiramisu (1 cup): 64 mg
  • Chocolate-covered coffee beans (2 Tbsp): 160 mg
  • Soft-serve chocolate frozen yogurt (8 oz): 9 mg
  • Chocolate-flavored instant breakfast (1 packet): 10 mg

Although most of these amounts are minimal they still contribute to daily intake.

Energy drinks and others with added caffeine

  • Monster or Rockstar (24 oz can): 238 mg
  • Red Bull (16 oz can): 143 mg
  • Mtn Dew Amp (16 oz can): 142 mg
  • Celsius (12 oz can): 200 mg
  • Celsius Heat (12 oz can): 300 mg

The caffeine amount stated on the label refers to the added caffeine. Energy drinks will contain more than this value if the beverage also contains ingredients containing caffeine such as guarana, yerba mate and "proprietary blends.

The Bottom Line

Caffeine, in adequate amounts, can be part of your healthy, balanced diet. Even more so, natural sources such as coffee, tea and chocolate can help you reap the health benefits of caffeine.

However, your age, health condition and genetics can affect how you metabolize caffeine. If you experience these side effects when consuming caffeine, lowering your intake can help. If you are unsure of how much caffeine you can consume, your best bet is to talk to your doctor.