what is it and how much is safe?

Caffeine is a bitter substance found in coffee, tea, soft drinks, energy drinks, chocolate, kola nuts and certain medicines. It has many effects on the body's metabolism, including stimulating the central nervous system. This can make you more alert and give you a boost of energy.

The US Food and Drug Administration (FDA) considers caffeine to be both a drug and a food additive. It is used in both prescription and over-the-counter medicines to treat tiredness or drowsiness and to improve the effect of some pain relievers. People with heart problems should not use caffeine because it makes their hearts work too hard, and people with anxiety problems or panic attacks may find that caffeine makes them feel worse.

As with most foods that don't contain essential nutrients, the key to caffeine intake is moderation.  The Academy of Nutrition and Dietetics says that 200 to 300 micrograms of caffeine per day (two to three cups of coffee) won't cause any negative effects.

side effects

Overconsumption of caffeine can cause anxiety, nervousness and digestive problems, and if consumed late in the day, it can prevent a good night's sleep according to the Academy of Nutrition and Dietetics

To learn more about symptoms and side effects from overdosing on caffeine visit the Overdose Symptoms website.

tolerance and withdrawal

When people use caffeine every day, their bodies get used to it and they develop a tolerance. Some studies show that caffeine causes a physical dependence or addiction. If a person gets withdrawal symptoms when they suddenly stop using caffeine, then the person has a physical dependence on caffeine. Withdrawal symptoms can include: severe headaches, muscle aches, temporary feelings of depression and irritability.

If you're feeling too dependent on caffeine to jumpstart your morning, Academy of Nutrition and Dietetics suggests you try these ideas to cut back on your consumption:

  • Cut your caffeine intake in half by mixing decaf and regular
  • Substitute coffee with decaffeinated and herbal teas
  • Eliminate other sources of caffeine from your diet, such as sodas, energy drinks, cocoa and some cold medicines (check ingredient labels)
Every caffeinated product has different caffeine content. Here are some examples:

Caffeinated Beverages

Caffeine (mg)











Dr. Pepper



Mountain Dew






Energy Drinks

Caffeine (mg)

Can Size (oz)




Red Bull



Rockstar & Monster



BooKoo Energy



Wired X505



Caffeine Pills

100-300 (mg)

1 pill


caffeine intoxication

The dangerous thing about energy drinks is that you can drink one and get 75 milligrams of caffeine, which is the amount in a cup of coffee, or you can drink one and get 500 milligrams, which could put someone who hasn't built up a tolerance to caffeine into caffeine intoxication, resulting in nervousness, anxiety, restlessness, insomnia, nausea, vomiting, tremors and rapid heart rate. A 19 year old boy died from consuming too many caffeine pills

Caffeine is also a diuretic, so manufacturers of energy drinks recommend consumers drink ample amounts of water, especially while exercising according to this Sport Journal article. 


mixing alcohol and energy drinks

The F.D.A reports that although there is little research on the effects of mixing caffeine and alcohol, several studies have suggested that people get more intoxicated and engage in riskier behavior when they drink the combination beverages than when they drink alcohol alone. Caffeine masks the effects of alcohol, doctors say, tricking users into believing they can keep drinking well past the point of drunkenness. Read the article here.


got sleep deprivation

The CDC  says that students who are working or studying long hours may experience episodes of sleep deprivation. This can cause daytime sleepiness, sluggishness, and difficulty concentrating or making decisions. Teens and young adults who do not get enough sleep are at risk for problems, such as automobile crashes; poor grades and school performance; depressed moods; and problems with friends, fellow students and adult relationships. 

One may think that if they can't sleep at night, they can just make up for it by drinking caffeine throughout the day, but this is a common misconception. Drinking caffeine throughout the day could be what's causing the insomnia!

natural energizers

Here are some quick tips on how to rest up so you can feel energized naturally:

  • Avoid or limit stimulants like caffeine and nicotine. The stimulating effects of caffeine in coffee, colas, teas, and chocolate can take up to 8 hours to wear off completely.
  • Have a good sleeping environment. Eliminate anything that might distract you from sleep, such as noises or bright lights.
  • Develop a sleep routine. Try to go to bed and wake up at the same time each day, even on the weekends.
  • Avoid pulling an all-nighter to study.
  • Most importantly, eat healthy, exercise, mantian a healthy weight and manage stress! Learn more about the American Heart Association's 5 Simple Heart- Healthy Energy Boosters!



For more information about Caffeine, please contact wellness@asu.edu.