What Happens If You Drink Too Many Monster Energy Drinks?

Caffeine is the primary active ingredient in Monster energy drinks. The drinks contain approximately 160 mg of caffeine in each 16 oz. serving. In comparison, the amount of caffeine in a cup of brewed coffee varies from 95 mg to 200 mg, depending on the source and type of coffee. Caffeine may have serious health effects when consumed in excess. Other active ingredients in Monster energy drinks include taurine, riboflavin, pyridoxine, nicotinamide and herbal derivatives. According to the medical journal "Drug and Alcohol Dependence," little is known about the safety of excessive acute and long-term consumption of these ingredients.

A man is chugging an energy drink outside. (Image: whitetag/iStock/Getty Images)

Risk Factors

People who drink energy drinks may be at a higher risk of caffeine toxicity compared with those who drink other caffeinated beverages such as coffee or soda. Since the drinks are marketed to young people, many drinkers are inexperienced in gauging appropriate caffeine intake and less tolerant to the effects. Advertisements for energy drinks usually promise improved performance, and some drinkers mistakenly think that "more is better." In addition, there are no labeling requirements and some drinkers may not know how much caffeine they are drinking.

Caffeine Toxicity

Signs of caffeine overdose include nervousness, anxiety, restlessness, insomnia, nausea and vomiting. More serious symptoms of acute caffeine toxicity include tremors, tachycardia or rapid heart rate, psychomotor agitation, high blood pressure, heart palpitations, dizziness, numbness and fainting. In rare cases, death has resulted from drinking too much caffeine. In one prominent case, an athlete experienced cardiac arrest following the consumption of 64 ounces of energy drink in five hours. Excessive consumption of energy drinks has also been linked to seizures, mania and stroke.

Dependence and Withdrawal

If you drink Monster energy drinks frequently, you may find it difficult to quit or cut back. The most common side effect of caffeine withdrawal is headache. Approximately one-half of regular caffeine drinkers experience headaches within 12 to 24 hours of their last dose of caffeine. Other symptoms of withdrawal may include fatigue, drowsiness, dysphoric mood, difficulty concentrating, decreased cognitive performance, depression and irritability. Some people also experience nausea and vomiting with muscle aches or stiffness. These symptoms may become severe and may disrupt your normal daily functioning.

Combination with Alcohol

Drinking energy drinks in combination with alcohol has become increasingly popular, particularly among young males. In two separate studies cited in the medical journal "Drug and Alcohol Dependence," 24 percent to 27 percent of college students reported drinking mixed energy drinks and alcohol. Nearly half of those students reported drinking three or more energy drinks per occasion. This combination is dangerous because users do not feel the symptoms of intoxication. They remain awake and continue to drink in larger quantities than they might have without the effects of caffeine. Students who drink mixed energy drinks and alcohol have a higher prevalence of alcohol-related consequences such as sexual assault, injury and driving while intoxicated or riding with a driver under the influence of alcohol.