How many cups of coffee kill you? (+7 sources)

In this article, we will answer the question “How many cups of coffee kill you?”, and how much caffeine is safe?

How many cups of coffee kill you?

It takes about 10g of caffeine to kill you. However, this figure varies from person to person. A cup of coffee contains about 100-200 mg of caffeine. While an energy drink provides 50-300 mg of caffeine. 

A can of soda provides less than 70 mg of caffeine. A single teaspoon of caffeine powder or tablet provides about 3,200 mg of caffeine. This means that you have to drink around 30 of the highly caffeinated energy drinks one after the other to get to 10g of caffeine which is the lethal dosage. 

This is quite rare because you cannot drink this much of any beverage in one sitting. Your body would naturally reject it. Acute symptoms of caffeine toxicity include nausea and vomiting.  

How much caffeine is safe?

The acceptable daily limit of caffeine is 400 mg for healthy adults or less than 2.5 mg per kilogram of body weight for healthy teens.

According to the American Academy of Pediatrics Trusted Source, the caffeine intake of adults aged 12 to 18 years should not exceed 100g per day. 

Younger kids should completely stay away from caffeine. Pregnant ladies should take no more than 200 mg of caffeine per day.

Sources of caffeine 

Other than candy, chewing gum, certain medications and supplements, and any energy booster food products, the following are common sources of caffeine.

Serving size Caffeine (mg)
Black coffee 1250-235
Black tea 830-80
Soda 1230-70
Red bull8.380
Chocolate bar (milk)1.69
NoDoz caffeine tablets1 tablet 200
Excedrin Migraine 1 tablet65

Causes and risk factors of caffeine overdose 

Caffeine overdose is the result of drinking or ingesting too much caffeine. Some people can take more caffeine than their daily recommended value without any health concerns. 

However, this practice on daily basis can lead to irregular heartbeat, seizures, and hormonal imbalances. People who rarely consume caffeine have become sensitive to it, therefore, they should avoid taking too much of it at once.

What are the symptoms of caffeine overdose?

Some of the common symptoms of caffeine overdose include dizziness, diarrhea, increased thirst, insomnia, headache, fever, and irritability. 

Severe symptoms that call for immediate medical attention include trouble breathing, vomiting, hallucinations, chest pain, irregular or fast heartbeat, confusion, uncontrollable muscle movements, and convulsions.

Diagnosing caffeine overdose 

If you experience any of the above-mentioned symptoms, you need to intimate your doctor about any of the caffeinated food, beverage, or supplement/medication you took prior to the symptoms. 

Your doctor will monitor your heartbeat, blood pressure, and breathing rate to make conclusions. He can also take your temperature or recommend a urine or blood test.

Treatment for caffeine overdose

Activated charcoal is commonly used to take the caffeine out of your system and prevent it from going into the GI tract. If the caffeine is already in the GI tract, you may be given a laxative or gastric lavage. 

A gastric lavage technique uses a tube to wash your stomach while monitoring your heat through an EKG. breathing support may also be provided If necessary. 

Side effects of too much caffeine 


Caffeine causes alertness by blocking adenosine and releasing adrenaline. Adenosine makes you feel tired while adrenaline increases the energy levels. Higher doses of caffeine result in pronounced effects of these hormones leading to Caffeine Induced Anxiety Disorder. 

A daily caffeine intake of 1000mg or more causes nervousness, jitteriness, and similar symptoms. The same symptoms may be triggered in caffeine-sensitive people even on the innate moderate dose. 


Caffeine interferes with your sleep.  the amount of caffeine intake you can consume without disturbing your sleep depends on your genetics and other factors. Typically, caffeine remains in your system for an average of five hours. 

For some people, It is 1 ½-9 hour. For an optimized sleep, you need to watch the amount of caffeine along with the time at which you are taking it.

Digestive issues

Caffeine acts as a laxative by promoting the release of gastrin hormone. These stimulated bowel movements might also be due to increased peristalsis. 

Therefore, caffeine overdose leads to diarrhea in some people. Coffee has been linked to causing gastroesophageal reflux disease (GERD) and stomach ulcers.

Muscle breakdown 

Rhabdomyolysis is caused when damaged muscle fibers make their way to the bloodstream causing renal failure and other complications. Though rare, caffeine has been studied as one of the causes of rhabdomyolysis. 


In this article, we answered the question “How many cups of coffee kill you?”, and how much caffeine is safe?


Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.

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