A dangerous caffeine overdose is unlikely from common sources of caffeine, but concentrated caffeine in energy drinks can cause a life threatening overdose.

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According to the National Library of Medicine, caffeine is the number one stimulant used by people around the World. A little caffeine can make you more alert and less tired. Too much caffeine can make you irritable and shaky. Although coffee is the main source of too much caffeine, a growing source is the concentrated caffeine in energy drinks and caffeine shots.

How much caffeine is too much?

The safe limit of caffeine for adults is 400 milligrams, which is about four cups of coffee, 10 caffeine colas, or two energy shots. Frequent coffee drinkers can tolerate more and for people who rarely drink coffee or are very sensitive to caffeine, less can be too much. For more on caffeine tolerance, read Can I Build a Tolerance to Caffeine. The limit of caffeine for pregnancy is 200 milligrams per day.

There is no safe limit of caffeine for children under age 12. Children ages 12 to 18 are advised to avoid caffeine energy products and limit caffeine from other sources to 100 milligrams (about 2 cans of caffeinated soda) per day.

Signs and symptoms of too much caffeine can include:

• Headache
• Nausea or loss of appetite
• Anxiety, agitation, and irritability
• Insomnia
• Palpitations
• Tremors
• Sweating and flushing
• Frequent urination

A dangerous caffeine overdose is unlikely from common sources of caffeine, but concentrated caffeine in energy shots, caffeine energy drinks, and powdered caffeine can cause an overdose and can be life threatening. Powdered caffeine is found in some supplements and can be purchased online. One teaspoon is equal to the caffeine in 28 cups of coffee.

Learn more about how too much caffeine can affect your brain function.

How long does it take to get caffeine out of your system?

Caffeine is broken down in your liver and excreted in your urine. It usually reaches its peak effects in about 45 minutes. After about 5 hours, half of the caffeine in your system will be eliminated, so symptoms of too much will usually be gone in four to five hours.

The best way to avoid too much caffeine is limit the amount. Remember that caffeine is also found in tea and chocolate. Try a decaffeinated soda or an herbal tea. Some over-the-counter (OTC) medications and supplements can add to your caffeine level. OTC medications for menstrual pain and migraine headache often have caffeine. Watch out for the supplements echinacea, yerba mate, and guarana.

There is not much you can do to speed up the process of getting caffeine out of your system, but you may be able to reduce the uncomfortable symptoms with these tips:

• Drink lots of water. This will avoid dehydration caused by frequent urination and may help flush some of the caffeine out of your system.
• Frequent urination may lower blood minerals called electrolytes. Replace them with a sports beverage like Gatorade or an electrolyte replacement fluid like Pedialyte.
• Stop adding any more caffeine from sources like chocolate or soda.
• Walk it off with walking exercise. This will lower your stress and anxiety.
• Trigger your inner relaxation response with deep breathing or a mind body exercise.

When cutting out caffeine completely, understand the symptoms of caffeine withdrawal.

When should you to get medical attention after consuming too much caffeine?

Symptoms of too much caffeine don’t need medical care, but if you have these symptoms along with confusion, hallucination, chest pain, shortness of breath, severe vomiting, or a seizure, seek medical help right away. You could have a serious caffeine overdose which needs to be treated as an emergency. Treatment may include breathing support, intravenous fluids, and medications to control blood pressure, heart rate, vomiting, and anxiety until the caffeine works its way out of your system.