Caffeine, an energy boosting chemical utilized for thousands of years, has come a long way since the Stone Age. Now, for thirsty drinkers looking for an energy boost, there are several varieties available offering either a minor caffeine kick or an extreme concoction of caffeine amidst other stimulants including ephedrine, taurine, ginseng, B-vitamins, guarana seed, carnitine, creatine, and more.

The enemy of all these ingredients is none other than adenosine, a neurotransmitter in the brain that aims to inhibit activity and promote sleep. Adenosine levels increase with the time we spend awake - so caffeine and its gang of fellow artificial neurotransmitters (listed above) that compose popular energy drinks like Monster, Red Bull, and Rockstar make it their mission to stifle adenosine's effects. Blocking the chemical hurls the body into a state of emergency that causes the release of adrenaline, the release of sugar from the liver into the bloodstream increased heartbeat, increased dopamine levels, and dilated pupils - all of which ultimately convince one's body that it is as energized as ever, despite having been awake for sixteen or so hours already.

On the flip side of the energy drink craze, chill-out and anti-energy relaxation drinks are entering the scene - their goal being to relax their drinkers without causing them drowsiness. These drinks also aim to address the issue of their energy drink competitors' tendencies to actually bring about stress, anxiety, and energy level crashes in the hours following their intake and initial energy high. Intended to deliver both relaxation and increased mental focus, they have already begun cutting into the energy drink market. Among these drinks are relatively new beverages called Slow Cow, Drank, Purple Stuff, Mini-Chill, Ex-Chill, Malava Relax, and Mary Jane's Relaxing Soda. Among their ingredients are:

• L Theanine, an amino acid from tea plants which is believed to not only induce relazation and feelings of well-being, but to also stimulate cognition, concentration, and mental awareness.

• Chamomile, a plant that reduces stress

• Passiflora, a group which encompasses a few hundred plants with properties that serve as both anti-depressants and relaxing agents.

• Valerian root, an herb that calms nervousness, sleepiness, anxiety and depression

• Hops, a plant known to calm nerves

• Kava, a Southern Pacific plant root with sedative properties

• Melatonin, a natural hormone used in jet lag and insomnia treatments

• Rose hips, a derivation of rose plants providing vitamin C and antioxidants

Still, even when it comes to these new energy drink alternatives, health concerns remain. Consuming these drinks in excess can trigger withdrawal symptoms after sudden disuse. Side effects of some of the individual ingredients include mild headache, upset stomach, abnormal heartbeat, insomnia, lower body temperature, and restricted blood flow. For now, however, the major concerns have come from health professionals speculating on the known effects of their ingredients - not from any significant number of the drink consumers themselves.