Caffeine: How Much Is Too Much?

Medically Reviewed

Are you addicted to the world’s most widely used “drug”—caffeine? Caffeine dependence, or “caffeine use disorder,” isn’t uncommon.

More than 90 percent of U.S. adults use caffeine regularly, with consumption averaging more than 200 milligrams (mg) a day, according to a scientific literature review published in the Journal of Caffeine Research. The Food and Drug Administration cites 400 mg daily as a safe amount or caffeine consumption for most healthy adults (about the amount in two to three 8-ounce cups of brewed coffee).

Consuming caffeine in higher doses can lead to negative health consequences. Abnormal heart rates, upset stomach, anxiety, depression, insomnia, nausea, irritability, tremors, and urinary incontinence are some examples of the downsides of high caffeine intake. Caffeine can also interact with drugs and, if consumed in large amounts, interfere with calcium absorption.

Despite potential health complications, many consumers become dependent on caffeine—one reason that experts at the World Health Organization recognize caffeine use disorder as a legitimate clinical disorder. The American Psychiatric Association (APA) calls for further study on the matter, writing that “caffeine use disorder relates to the potential addictive behavior caused by excessive, sustained consumption of caffeine,” but stops short of labeling it as a clinical diagnosis.

In a survey of 500 members of six professional organizations that focus on addiction, 58 percent of respondents believed that caffeine use disorder exists. Less than half felt that caffeine use disorder should be classified with other addiction and mental health disorders. Yet, most respondents (95 percent) believed that stopping caffeine could lead to withdrawal symptoms. Sixty percent agreed that some people could benefit from professional help for quitting or reducing caffeine use.

Should you scale back?

The review found that 33 percent of caffeine users reported they need caffeine to function. According to the APA, you may be dependent on caffeine if you experience all three of the following over 12 months:

A persistent desire or unsuccessful efforts to cut down or control caffeine use.

Continued caffeine use despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by caffeine.

Withdrawal, as manifested by either the characteristic withdrawal syndrome for caffeine, or taking caffeine (or a closely related substance) to relieve or avoid withdrawal symptoms.

Like any addictive substance, feelings of withdrawal can trump the need to quit. When deprived of caffeine, you may experience headaches (which can be severe), cravings, nervousness, fatigue, irritability, depression, drowsiness, problems concentrating, and flu-like symptoms, any of which can cause significant distress and impair daily function. Withdrawal symptoms occur within 12 to 24 hours of stopping caffeine intake and can last from two days to one week.

Besides the criteria above, other signs that you may be dependent on caffeine include the inability to fulfill major responsibilities at work or home, insistence on using caffeine even when it affects health and relationships, and caffeine tolerance—when you need to increase consumption to achieve the effects you felt in the past with smaller amounts.

Other clinical disorders related to caffeine consumption include caffeine intoxication, caffeine withdrawal, caffeine-induced sleep disorder, and caffeine-induced anxiety disorder.

Our advice

If you want to quit caffeine or reduce intake, try replacing caffeinated beverages with decaffeinated ones or transition to low- or no-caffeine products. Do this slowly to minimize withdrawal symptoms. Also, look out for unexpected sources of caffeine, such as over-the-counter cold and pain medications (which can contain about 30 mg of caffeine per tablet), coffee-flavored ice cream or yogurt (up to 85 mg a cup), and soft drinks (Mountain Dew has 54 mg per 12-ounce serving).