If you’re as addicted to caffeine as I am, this science-backed intel might help you sleep at night.

By Betty Gold
March 24, 2021

If you're anything like me, you don't really think of coffee as a "warming morning beverage" or a "fun little treat to start the day" anymore. Nah, coffee is a lifeline. My delicious little crutch recharges my battery at all hours—and in various forms, from French-press and pour-over to dirty chais, cold brew, and even cocktails.

Clearly, I'm on the extreme end of the spectrum. Eventually, I'll jump on the "cutting back" bandwagon, and I'm sure my chronic insomnia will thank me. (Here are a few great coffee alternatives plus ways to boost energy sans coffee if you're caffeine free-curious, too).

But here's the thing: Caffeine isn't bad for you when consumed in moderation. To figure out what exactly moderation means and what health benefits—and drawbacks—caffeine has to offer, we checked in with nutrition expert Megan Meyer, PhD, director, science communications at the International Food Information Council.

What Health Benefits Does Caffeine Offer?

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. 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. 

"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 show to protect against chronic diseases," Meyer adds. 

Can Caffeine Be Harmful to Your Health?

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," Meyer explains.

The FDA states that consuming about 1,200 milligrams of caffeine can potentially cause 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."

Does the Source of Caffeine Matter, Health-Wise?

How does coffee stand up next to tea, energy drinks, and so on? "The body does recognize the difference between natural vs. synthetic caffeine. In fact, according to the 2020 IFIC Food & Health Survey, over the past five years, Americans have trended towards believing that naturally occurring and added caffeine have the same effect," explains Meyer. What matters the most and is recommended by the FDA and US Dietary Guidelines for Americans is that you stay below 400 milligrams, since that amount is not associated with negative health effects in healthy adults. "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."

What Does a Healthy Amount of Caffeine Look Like?

According to Meyer, moderate caffeine consumption is in the range of 300 to 400 milligrams per day (mg/day). That's about three cups of coffee, 5 ounces of espresso, seven cups of black tea, or 11 cups of green tea. If you're unsure how much caffeine is in common foods or beverages, check out the International Food Information Council's caffeine calculator

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


Brewed coffee

8 ounces


Brewed coffee, decaf

8 ounces



1 ounce


Black tea

8 ounces


Green tea

8 ounces


Coca-Cola—Regular or Zero Sugar

12 ounces


Red Bull—Regular or Sugar-Free

8.4 ounces


Starbucks Coffee, Pike Place Roast

16 ounces (Grande)


Hershey’s Milk Chocolate

1.5 ounces


Tips for Those Trying to Cut Back Their 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 keep an eye on 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.