How much caffeine is too much?

Caffeine does more than just provide a boost of energy. For many, it’s a daily ritual.

A morning cup of coffee can make leaving a warm bed slightly more bearable. A shot of espresso can perk you up during that afternoon slump. Maybe you even rely on the occasional energy drink to fuel a late-night study session.

But you might wonder how it impacts your health. How much is too much? And is there anything we can do to make our caffeinated drinks healthier?

Clinical dietitian Kaylie Brown helps answer these questions and more.

How does caffeine work?

You likely already know how the right amount of caffeine makes you feel: fueled and ready to take on the day. But how else does caffeine affect the body?

The National Institutes of Health’s National Library of Medicine writes that caffeine can:

• Stimulate the central nervous system
• Act as a diuretic, increasing urination
• Cause your body to release more stomach acid
• Possibly impact calcium absorption
• Raise blood pressure

How much caffeine is too much?

Most adults can consume about 400 milligrams of caffeine per day without negative effects, the Food and Drug Administration (FDA) writes.

“A typical dose of caffeine is around 70 to 100 milligrams per drink,” Brown says.

But many caffeinated beverages, like the pot of coffee in your office or a to-go latte, don’t come with ingredient labels that say exactly how much caffeine they contain.

Resources like the National Library of Medicine provide general caffeine ranges for popular beverages. This can help you get a better idea of how much caffeine you are consuming.

• Coffee (8 ounces): 95-200 milligrams
• Energy drink (8 ounces): 70-100 milligrams
• Cola (12 ounces): 35-45 milligrams
• Tea (8 ounces): 14-60 milligrams

What factors impact caffeine tolerance?

While general caffeine recommendations can give you a sense of how much caffeine is safe to consume, caffeine intake varies from person to person. That means your caffeine intake might look different from that of a friend who can drink coffee late into the afternoon and still manage to fall asleep without issue.

Brown says caffeine tolerance can vary based on factors such as:

• How much caffeine you drink
• How quickly you drink it
• How long it takes your body to eliminate the caffeine
• Body composition
• Caffeine sensitivity
• Medications
• Health conditions

What happens when you have too much caffeine?

Your body can provide you with some helpful signs that you’ve over-caffeinated. Brown notes that symptoms of drinking too much caffeine include:

• Increased heart rate
• Heart palpitations
• High blood pressure
• Insomnia
• Sleep disturbances
• Anxiety
• Jitters
• Gastrointestinal upset
• Nausea
• Headaches
• Seizures

Is decaf better than a caffeinated drink?

Much like your unique coffee order, this answer might look different from one person to the next.

“I think that making these decisions depends on intake, overall health goals, and tolerance and side effects,” Brown says.

A registered dietitian or doctor can help you decide if drinking caffeine is a good choice for you.

Ready to dabble in the world of decaf? Keep in mind that cutting out caffeine abruptly can have side effects like headaches, fatigue and drowsiness, Brown says.

“If you choose to cut back on your caffeine intake, I recommend doing so gradually,” she says.

Another tip? If you’re trying to use medication to relieve a headache caused by a lack of caffeine, Brown says to check that it doesn’t contain more caffeine.

Should anyone avoid caffeine altogether?

It depends. Caffeine isn’t recommended for people who have certain medical conditions or who are taking some medications, Brown says.

For example, she recommends that people with the following medical conditions watch their caffeine intake:

• Gastroesophageal reflux disease (GERD)
• Heart disease
• Hepatic impairment
• Hypersensitivity
• Iron deficiency anemia
• Peptic ulcer disease
• Pregnancy
• Kidney and/or urinary impairments
• Seizures
• Severe anxiety
• Irregular heartbeats

Still unsure whether it's safe for you to consume caffeine? It’s best to consult with your care team.

Is caffeine safe for cancer patients?

The answer to this question will look different for each person.

Here are a few factors Brown says play into whether it’s safe for someone in cancer treatment to consume caffeine.

• Medication
• Medical and surgical history
• Side effects, such as dehydration and diarrhea 

“It is best to work with your medical team to determine what’s best for you,” she says.

How can we make caffeinated beverages healthier?

Caffeine can affect your health, but so can other beverage choices.

“The largest concerns with coffee intake and health are less directly related to moderate amounts of caffeine consumption, but rather the habits around those beverages,” Brown says. 

For example, while the amount of caffeine in some specialty coffee or energy drinks may be well within the FDA’s safe daily caffeine recommendations, some can single-handedly account for more added sugar than it is recommended to consume in a day. Likewise, dairy products like milk, cold foam and creamer can be high in trans-fat and saturated fat.

If you’re looking for healthier ways to change up the taste of your coffee, here are Brown's suggestions.

• Flavor it with cinnamon or nutmeg.
• Use natural sugars like maple syrup or pasteurized honey rather than artificial sweeteners. These options are still added sugar, but it doesn’t take much to sweeten your drink — try starting with a teaspoon or two. This can ultimately help you consume less sugar overall. 
• Not a fan of strong coffee? Rather than add sweetener, try adding skim or low-fat milk or water.

“It is OK to add small amounts of items like sugar, creamer or flavorings to your coffee,” Brown says. “However, be mindful to check the ingredient list and monitor overall intake of excess calories and added sugar as this could contribute to excess weight gain.”

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