Caffeine: How Much Is Too Much? - Mayo Clinic

Maybe your like

Caffeine: How much is too much?

Caffeine has its perks, but it can pose problems too. Find out how much is too much and if you need to cut down.

By Mayo Clinic Staff

If you use caffeine to wake you up and keep you going, you aren't alone. Millions of people use caffeine every day to stay alert and concentrate better.

How much is too much?

Up to 400 milligrams (mg) of caffeine a day seems safe for most adults. That's about the amount of caffeine in four cups of brewed coffee, 10 cans of cola or two "energy shot" drinks. Keep in mind that the caffeine content in drinks varies widely.

The U.S. Food and Drug Administration warns that caffeine in powder or liquid form can give toxic levels of caffeine. Just one teaspoon of powdered caffeine is equal to about 28 cups of coffee. Such high levels of caffeine can cause serious health problems, including death.

Caffeine use may be safe for adults, but it's not a good idea for children. Teens and young adults need to know about too much caffeine and mixing caffeine with alcohol and other drugs.

People who are pregnant or trying to become pregnant and those who breastfeed should talk with their healthcare professionals about limiting caffeine.

Even among adults, heavy caffeine use can cause bad side effects. And caffeine may not be a good choice for people who react to its effects or who take certain medications.

Read on to see if you may need to cut caffeine.

You drink more than 4 cups of coffee a day

You may want to cut back if you're drinking more than four cups of coffee with caffeine a day or if you have side effects such as:

Headache.
Not being able to sleep, called insomnia.
Being nervous or cranky.
Urinating often or not being able to control urinating.
Fast heartbeat.
Shaky muscles, called muscle tremors.
Stomach upset.

Even a little makes you shaky

Caffeine affects some people more than others. If caffeine affects you, even small amounts may give you effects that you don't want, such as being restless or not being able to sleep.

How you react to caffeine may depend in part by how much caffeine you drink. If you don't drink daily, you might react more to it.

You don't get enough sleep

Caffeine can keep you from sleeping. Even small amounts of sleep loss can add up. The loss can keep you from being alert the next day.

Using caffeine to make up for your lack of sleep can be a problem. For instance, you may use caffeine to help keep you awake during the day. But the caffeine keeps you from falling asleep at night. So you get less sleep, which makes you more tired the next day.

You take medicines or supplements or have certain conditions

Caffeine can have effects on medicines or supplements you take. It also may increase symptoms of some conditions such as anxiety, urinary incontinence or seizure disorders.

When a healthcare professional gives you a prescription for a new medicine, talk about how much coffee or tea you drink. Ask if that could be a problem with that medicine. Ask a pharmacist about medicines you get without a prescription.

It's safe to drink some caffeine with most medicines. But you should not have caffeine if you take medicine that has ephedrine. The mix could raise the risk of high blood pressure, heart attack, stroke or seizures in some people.

For that reason, use herbal supplements, such as ma huang, with care. Some supplements have a natural source of ephedra. For your safety, tell your healthcare professional about any medicine or supplements you take.

Cutting back on caffeine

Suddenly cutting caffeine may cause withdrawal symptoms. These may include headaches, tiredness, crankiness and having trouble focusing. Most often, these symptoms are mild and get better after a few days.

To change your caffeine habit, try these tips:

Keep track. Notice how much caffeine you get from foods and drinks, including energy drinks. Check labels. But know that you might not be counting all your caffeine because some foods or drinks with caffeine don't list it on the label.
Cut back little by little. Maybe drink one fewer can of soda or drink a smaller cup of coffee each day. Or don't drink beverages with caffeine late in the day. This will help your body get used to the lower levels of caffeine, so withdrawal effects may be less.
Try decaf. Having less caffeine in a drink most often doesn't affect the taste. But keep in mind that decaf still has some caffeine.
Brew tea for less time or use herbal tea. Brewing tea for less time cuts down on caffeine. Or choose herbal teas that don't have caffeine.
Check labels. Some pain relievers you get without a prescription have caffeine in them. Look for caffeine-free pain relievers instead. Other products, such as energy bars and many packaged foods, may have caffeine, as well.

The bottom line

If you're like most adults, you use caffeine every day. Most often, it won't cause a health problem. But be aware of caffeine's possible side effects and be ready to cut back if needed.

There is a problem with information submitted for this request. Review/update the information highlighted below and resubmit the form.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

Email Address 1 Learn more about Mayo Clinic’s use of data.

We use the data you provide to deliver you the content you requested. To provide you with the most relevant and helpful information, we may combine your email and website data with other information we have about you. If you are a Mayo Clinic patient, we will only use your protected health information as outlined in our Notice of Privacy Practices. You may opt out of email communications at any time by clicking on the unsubscribe link in the email.

Subscribe!

Thank you for subscribing!

You'll soon start receiving the latest Mayo Clinic health information you requested in your inbox.

Sorry something went wrong with your subscription

Please, try again in a couple of minutes

Retry

Feb. 21, 2025 Show references

Spilling the beans: How much caffeine is too much. U.S. Food and Drug Administration. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much. Accessed Oct. 28, 2024.
2020-2025 Dietary Guidelines for Americans. U.S. Department of Health and Human Services and U.S. Department of Agriculture. https://www.dietaryguidelines.gov. Accessed Oct. 28, 2024.
Bordeaux B. Benefits and risks of caffeine and caffeinated beverages. https://www.uptodate.com/contents/search. Accessed Oct. 28, 2024.
Antonio J, et al. Common questions and misconceptions about caffeine supplementation: What does the scientific evidence really show? Journal of the International Society of Sports Nutrition. 2024; doi:10.1080/15502783.2024.2323919.
Caffeine. Natural Medicines. https://naturalmedicines.therapeuticresearch.com. Accessed Oct. 28, 2024.

See more In-depth

Products and Services

10+ women's health supplements available at the Mayo Clinic Store.
A Book: Cook Smart, Eat Well
A Book: Live Younger Longer
A Book: Mayo Clinic Family Health Book
A Book: Mayo Clinic Guide to Home Remedies
A Book: Mayo Clinic on Digestive Health
A Book: Mayo Clinic on High Blood Pressure
A Book: The Mayo Clinic Diet Bundle
A diverse range of multivitamins can be found at the Mayo Clinic Store.
A wide array of Bone & Joint Health supplements from the Mayo Clinic Store.
Available Health Products from Mayo Clinic Store
Brain Health Supplements
Digestive health supplements available at the Mayo Clinic Store
Heart Health Supplements
Newsletter: Mayo Clinic Health Letter — Digital Edition
The Mayo Clinic Diet Online

Caffeine: How Much Is Too Much? - Mayo Clinic