Taurine is an amino acid found throughout the body, but chiefly in nerve tissue and muscle. It is thought to help regulate heartbeat and muscle contractions, water balance, energy levels and levels of neurotransmitters in the brain. Read the full description
Carnitine is an amino acid that is synthesized in the liver and kidneys from lysine and methionine. The major function of carnitine is to facilitate the transport and metabolism of long-chain fatty acids into the mitochondria for beta-oxidation and energy generation. Read the full description
Guarana comes from the seeds of a South American shrub - most of which originates in Brazil. Traditional uses of guarana by natives of the Amazonian rain forest include crushed seeds added to foods and beverages to increase alertness and reduce fatigue. Read the full description
Caffeine is classified as a trimethylxanthine and is found in coffee, tea and a number of over the counter medications. Caffeine has well known stimulant properties and is probably the most widely consumed "herbal" supplement in the world. Read the full description
"Absolutely! We have extensively researched our energy blend for both safety and effectiveness. Millions of cans have been consumed with no report of adverse effects." This was taken from the FAQ section on Monster's website. It is not related to all "energy drinks". Monster Energy
Kim Peterson, a spokeswoman for Red Bull, said the beverage is uplifting because it contains vitamins and amino acids, such as taurine. On its Web site, the company says taurine "acts as a metabolic transmitter and additionally has a detoxifying effect and strengthens cardiac contractility." - Read this article
"It just becomes more of a witches brew. You're playing with things that we don't really understand and the long-term consequences are unclear," says Hirt, medical director at the Center for Integrative Medicine at the Encino-Tarzana Regional Medical Center in Encino, Calif. - Read this article
"Individual responses to caffeine vary, and these drinks should be treated carefully because of how powerful they are. Energy drinks' stimulating properties can boost the heart rate and blood pressure (sometimes to the point of palpitations), dehydrate the body, and, like other stimulants, prevent sleep." - Read this article
I'm not a doctor, nor a leading authority on energy drinks. In my internet researching, I was only able to find two negative effects of drinking energy drinks. The first being excessive consumption. Just like coffee and soda, most energy drinks contain caffeine. The other negative effect would include mixing energy drinks with alcohol. There are many arguments about mixing energy drinks with alcohol on the internet. In my opinion, mixing one drink with alcohol wouldn't kill you, but who drinks only one alcoholic drink when they go out? So, be careful how you chose to consume energy drinks.