The Caffeine In 5-hour Energy Drink

Sleep problems affect more than 70 million Americans, according to the National Institutes of Health, and sleep problems at night can leave you tired and dragging in the morning and occasionally looking for a quick pick-me-up from an energy drink. Caffeine is the primary stimulant in 5-Hour Energy drinks. In addition to countering sleepiness, caffeine temporarily increases your mental alertness.

Caffeine Dose

The manufacturer of 5-Hour Energy drinks does not reveal the amount of caffeine in the regular and maximum-strength products. But according to Consumer Reports Health, independent testing conducted by ConsumerLab.com in October 2010 revealed 207 mg of caffeine per 1.93-ounce bottle of original 5-Hour Energy. This represents approximately seven times the amount of caffeine in a 12-ounce can of cola and more than twice the amount in a cup of brewed coffee. Maximum strength 5-Hour Energy contains more caffeine than the original formula, although the precise amount is unknown. The manufacturer states that Decaf 5-Hour Energy contains 6 mg of caffeine per 1.93-ounce bottle, approximately three times the amount in a cup of decaffeinated coffee.

Stimulant Effects

Chemicals called neurotransmitters control the electrical traffic in your brain by either augmenting or dampening nerve cell signaling. Caffeine enters your brain and competes with adenosine, a signal-dampening neurotransmitter. By blocking the dampening effects of adenosine, caffeine leads to a moderate increase in brain signaling and nervous system stimulation. Although you feel more energetic when your nervous system is stimulated by caffeine, 5-Hour Energy is not a source of metabolic energy.

Potential Side Effects

Depending on your sensitivity to caffeine and how much 5-Hour Energy you have consumed, you may experience overstimulation from the caffeine in this drink. Potential side effects include jitteriness, nervousness, tremors, irritability, muscle twitches, sweating, heart palpitations and increased urination. You may experience difficulty falling asleep if you consume 5-Hour Energy too close to your bedtime. You also may experience a "crash," in which your feel profoundly tired after the caffeine is excreted from your body. Severe caffeine intoxication may cause hallucinations, nausea, vomiting, seizures and difficulty breathing. If you experience any of these symptoms, seek emergency medical assistance. The manufacturer of 5-Hour Energy states that you should not consume more than two bottles within a five-hour period.

Other Ingredients

When you drink 5-Hour Energy, you consume a variety of substances in addition to caffeine. Each bottle contains high doses of several B complex vitamins, including B-6, B-12, niacin and folic acid. The drink also contains the amino acids phenylalanine, tyrosine and taurine. Other ingredients include the artificial sweetener sucralose and the preservatives sodium benzoate, potassium sorbate and EDTA.