Need your morning fix? Learn the pros and cons of caffeine and how much is too much

The pros and cons of caffeine still get debated in medical and nutrition circles alike. It's the world’s most commonly consumed drug, with 80 percent of Americans using caffeine daily. Learn some surprising caffeine benefits and potential downsides.

What are the pros and cons of caffeine?

Caffeine pros

Caffeine indeed offers the boost that many of us look for, such as increasing mental alertness, especially among occasional users.

Caffeine can help migraine and tension headache sufferers, especially when included with pain medication. The US Food and Drug Administration (FDA) has approved caffeine for these uses.

Athletes often turn to caffeine as a sports performance aid, providing a slight increase in athletic strength and endurance. The National Collegiate Athletic Association limits the level of caffeine detected in collegiate athletes' urine to 15 micrograms (mcg) per milliliter. This corresponds to roughly 500 milligrams (mg) of caffeine or six to eight cups of brewed coffee.

According to an extensive review published in the British Medical Journal, coffee drinkers have a lower risk of liver cancer, fatty liver disease, and gallbladder disease.

Coffee and tea drinkers tend to have a lower risk of type 2 diabetes. However, caffeine’s effects on people with existing diabetes appear mixed.

You may feel better about grabbing that extra cup of coffee, knowing these potential caffeine benefits. Still, they don’t show cause and effect. There’s no reason to start drinking caffeinated beverages if you don’t care for them or like how they make you feel.

Will caffeine help you lose weight? Coffee drinkers tend to have a slightly lower BMI, but there is inconsistent evidence for caffeine lowering one's appetite. A review of green tea studies found an association between green tea consumption and decreased body weight and body fat.

If your favorite coffee drink is full of cream and sweeteners, or you must pair baked goods with your mid-morning coffee, caffeinated coffee won’t help your weight-loss goals.

Caffeine cons

You may notice caffeine pitfalls, even if you only drink a cup or two of coffee or tea. Common caffeine side effects include rapid heartbeat, jitteriness, and sleep difficulties. Digestive side effects include diarrhea and heartburn.

Caffeine may cause frequent urination and bladder irritation. Despite popular belief, caffeine does not cause dehydration for regular users.

Any long-term coffee drinker knows that caffeine is habit-forming. If you choose to give up caffeine, do so gradually to avoid the misery of caffeine-withdrawal headaches.

How much is too much?

The British Journal of Medicine review concluded that there are no significant health risks with caffeine intake up to 400 mg (about 4 cups of coffee) per day in healthy adults. Likewise, the FDA states that up to 400 mg of caffeine is not associated with dangerous side effects.

Higher caffeine intake and caffeine use in children, people who are pregnant, elderly adults, and those with existing medical conditions may present more risk. The American College of Obstetricians and Gynecologists recommends people who are pregnant or breastfeeding limit caffeine to 200 mg daily (roughly one 12-ounce cup of coffee)

Individual differences

Do you find yourself jittery after just one cup of coffee while your friend can drink a pot with no problem? Genetics may explain the difference. How people process caffeine varies significantly. Blood caffeine levels usually peak about one to two hours after consumption. The rate at which people break down half of the caffeine in their body can range from two to ten hours. Caffeine can also affect people differently based on their tolerance and usual intake.

How much caffeine are you getting?

Beverage/Food	Portion	Caffeine (mg)
Coffee, brewed, black, decaffeinated	8 fl oz	2
Espresso	1 fl oz (one "shot")	64
Coffee, brewed, black	8 fl oz	95
Tea, green	8 fl oz	29*
Tea, black	8 fl oz	47*
Hot cocoa from mix	6 fl oz	4
Milk chocolate	1 oz	6
Dark chocolate	1 oz	23
Pepsi	12 fl oz	38**
Red Bull	8 fl oz	75
Extra Strength 5-hour ENERGY shot	1.93 fl oz	230**
Celsius	12 fl oz	200**

* Caffeine will vary based on steeping time.

** See manufacturer website for caffeine content.

How to track your caffeine intake

You can monitor your daily caffeine consumption with MyNetDiary. Go to Configure Dashboard and add caffeine. If a food is missing caffeine data (i.e., the manufacturer does not supply it), you can save it as a Custom Food and insert caffeine information. Caffeineinformer.com has a wealth of caffeine information for common foods and beverages. Such resources will help you weigh the pros and cons of caffeine for yourself.

Still new to MyNetDiary? Learn more today by downloading the app for FREE.

Updated by Amy Brownstein, MS, RDN on Aug 27, 2025

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Alcohol & Other Beverages->Coffee & Tea Nutrients->Caffeine