Weighing the risks of caffeine: How much caffeine is safe and how to know when you’ve had too much

It’s been rocky year for caffeine.
It’s been rocky year for caffeine. | Mike Terry , Deseret News

How much caffeine is too much?

A string of recent events have led to headlines about the stimulant and prompted consumers to pay more notice at how much caffeine is contained in a single beverage.

In July, Sen. Charles Schumer, D-N.Y., called upon the Food and Drug Administration to investigate Prime drinks — a caffeinated beverage popular among tweens.

“Who is the main target of PRIME? It’s kids under 18,” Schumer wrote in his letter to the FDA, per CBS News. “The problem here is that the product has so much caffeine in it that it puts Red Bull to shame.”

A recently published Atlantic article titled “Caffeine’s dirty little secret” referenced the controversy surrounding Panera’s charged lemonade beverage. The drink, which contains 237 milligrams per serving, was listed in two 2023 wrongful death lawsuits. Following the second lawsuit, Panera stated that Dennis Brown’s death was “not caused by one of the company’s products,” per ABC News.

During the late aughts, highly caffeinated energy shots and energy drinks were scrutinized by the Food and Drug Administration when dozens of reports cited caffeinated drinks in connection to serious injury, as reported by The New York Times. During subsequent years, the FDA has periodically been called upon to tighten regulations regarding caffeinated beverages.

Though caffeine is widely considered to be safe when consumed in moderation, per the Mayo Clinic, everyone has a unique tolerance for the stimulant. When consumed in excess, caffeine can be harmful.

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How much caffeine is too much?

Caffeine tolerance is different for everyone. Those who consume caffeine regularly likely have a higher tolerance than those who infrequently consume caffeine, per the FDA. Healthy adults typically have a higher tolerance than teenagers and children.

Healthy adults can typically consume 400 milligrams of caffeine per day without negative side effects, according to the FDA. But it is important to note that everyone metabolizes caffeine differently. Some conditions and medications can increase caffeine sensitivity.

“Up to 400 milligrams (mg) of caffeine a day appears to be safe for most healthy adults. That’s roughly the amount of caffeine in four cups of brewed coffee, 10 cans of cola or two ‘energy shot’ drinks,” reports the Mayo Clinic. “Keep in mind that the actual caffeine content in beverages varies widely, especially among energy drinks.”

According to the Mayo Clinic, some typical (non-threatening) side effects from caffeine include:

  • Headache.

  • Irritability.

  • Trouble sleeping or insomnia.

  • Anxiety.

  • Increased heart rate.

  • Frequent urination.

  • Twitching.

If you experience any of these symptoms, it may be advantageous to limit your daily caffeine intake.

Additionally, not all caffeine is created equal. For example, caffeine pills generally contain 100 milligrams to 200 milligrams of caffeine each, per Medical News Today. An 8-ounce cup of tea contains about 40 milligrams of caffeine, an 8-ounce cup of coffee contains around 90 milligrams and an 8-ounce energy drink contains up to 250 milligrams of caffeine.

Before consuming a caffeinated beverage, read the label so you are aware of how much caffeine you are consuming throughout the day.

Symptoms of caffeine overdose — and when to see a doctor

Caffeine overdose — also known as caffeinism — is rare, but it does happen. To reach a point of caffeine intoxication, it typically takes the “rapid consumption” of 1,200 milligrams of a caffeinated beverage, per the FDA.

If you have consumed a potentially dangerous amount of caffeine, according to University of Utah Health, you may experience the following symptoms:

  • Tremors.

  • Vomiting or upset stomach.

  • Sweating.

  • Heart palpitations.

  • Headache.

  • Diarrhea.

  • Delirium.

  • Chest pains.

“In the most severe cases of caffeine toxicity, the heart and nervous system can be impacted. In high doses, caffeine can also lower blood pressure,” per University of Utah Health. “Caffeine stimulates the central nervous system—that’s the jittery feeling—which can lead to agitation and ultimately cause delirium and seizures.”

If you are experiencing any symptoms of a caffeine overdose, seek medical care immediately. Do not attempt to treat the symptom from home. Call your local emergency number, local poison control number or your physician for professional help.

How much caffeine is in popular caffeinated beverages?

A 12-ounce can of soda may contain a wildly different amount of caffeine than a 12-ounce energy drink. Below shows the amount of caffeine contained in popular caffeinated beverages, provided by the Center for Science in the Public Interest.

  • Bang (16 ounces): 300 milligrams.

  • Diet Coke (12 ounces): 46 milligrams.

  • Dr. Pepper (12 ounces): 41 milligrams.

  • Dunkin’ Coffee (14 ounces): 210 milligrams.

  • Monster Energy (16 ounces): 160 milligrams.

  • Pepsi (12 ounces): 38 milligrams.

  • Prime Energy (12 ounces): 200 milligrams.

  • Redbull (8 ounces): 80 milligrams.

  • Rockstar (16 ounces): 160 milligrams.

  • Starbucks Coffee, Pike Place Roast (16 ounces): 310 milligrams.

  • 5-Hour Energy (1.9 ounces): 200 milligrams.