There are a huge number of drinks out there that claim to help increase your energy level.  A good number of these drinks come in sugar free versions, offering the best of two worlds, increased performance/energy and zero calories.  What could be better? 

GeekHealth.org takes a look at Sugar Free NOS, which is labeled as a "High Performance Energy Drink".  It comes in a bright orange 16oz can, and besides the standard nutritional information there is a special "Energy Blend" section.  Just looking over it you get the feeling that what’s inside should boost your energy levels through the roof, but just what are they putting in there, and just what are you putting in your body?

Carbonated Water

Water that has carbon dioxide gas(CO2) dissolved in it.  Carbonated water is acidic from the formation of carbonic acid, and can contribute to the thinning of tooth enamel as well as contributing to a more acidic blood pH.   Both conditions are unlikely to be caused by the normal consumption of simple carbonated water, but soft drinks are usually much higher in acid content from the addition of other acids such as phosphoric acid and citric acid.

Citric Acid

Natural organic acid found in a variety of fruits and vegetables.  It is a natural preservative and has an acidic or sour taste.

Taurine

An organic acid, found naturally in seafood and meat.  Taurine is listed on NOS as part of their “Energy Blend” and was listed as 1,000mg.  One study by the College of Pharmacy-West Palm Beach, found that “The amounts of guarana, taurine, and ginseng found in popular energy drinks are far below the amounts expected to deliver either therapeutic benefits or adverse events.” http://www.ncbi.nlm.nih.gov/pubmed/18595815

Sodium Citrate

This is most likely Trisodium citrate.  Trisodium citrate is used in foods as a flavoring agent and preservative.  Trisodium citrate is also used to regulate acidity.  Trisodium citrate can be used medically as an anticoagulant during blood transfusions.

Passion fruit

Flavoring

L-Carnitine

NOS lists this in the “Energy Blend” and includes 200mg in its sugar free drink.  Some studies do conclude that Carnitine taken orally may help reduce fat mass, http://www.umm.edu/altmed/articles/carnitine-l-000291.htm.

Caffeine

See http://www.geekhealth.org/post/2009/11/13/Caffeine-The-worlds-most-used-legal-drug.aspx

Sodium Hexametaphosphate (preservative)

Used as a sequestrant

Inositol

NOS lists this in the “Energy Blend” and includes 100mg in its sugar free drink.   There is no doubt that Inositol is helpful to normal bodily functions such as : metabolism, preventing fatty deposits in the liver, and promoting healthy hair growth.  The amount used here (100mg) is generally considered too low to have any real health impact but some people attest that greater daily intake of Inositol is beneficial. http://www.wisegeek.com/what-is-inositol.htm

Monopotassium Phosphate

If you check out Wikipedia you might question why this substance is in your drink (http://en.wikipedia.org/wiki/Monopotassium_phosphate) although it is commonly used in the foods as a buffer and emulsifier. 

Gum Arabic

Natural gum that can be found in the sap of acacia trees and most likely included in NOS for its surface tension reducing properties.  i.e. It makes the drink bubble easier.

Sodium Benzoate (preservative)

Used for its antibacterial and antifungal properties, sodium benzoate is a powerful preservative found in many foods.  When combined with ascorbic acid sodium benzoate can form benzene which is a known carcinogen.  There is a good deal of debate on the use of sodium benzoate as a food additive because of its ability to form benzene. http://www.sciencepunk.com/2007/05/e211-dna-and-science-by-press-release/

Potassium Sorbate (preservative)

Used to control the growth of yeasts and molds.  This is a very common ingredient in many food items.

Acesulfame Potassium

FDA approved for use as an artificial sweetener.

Sucralose

Best known as Splenda, it is another artificial sweetener.  Sucralose is still a very controversial artificial sweetener.  Its not too difficult to find people warning about the use of Sucralose in food products.

Sites warning people of the potential toxic effects of Sucralose:

http://www.holisticmed.com/splenda/bowen.html

http://www.holisticmed.com/splenda/chemists.html

http://www.rense.com/general65/splend.htm

http://tuberose.com/Sucralose.html

Ester Gum

Used as an emulsifier and stabilizer in food products.  This is a very common ingredient in soft drinks.

Panax Ginseng Root Extract

This is an Asian ginseng root, and listed in the NOS “ Energy Blend” which contains 50mg of ginseng extract.  Ginseng is usually taken as a supplement for its inflammatory properties.  Some suggest that Ginseng can also reduce stress, improve overall energy levels, and even fight Chronic Fatigue Syndrome.

Calcium Disodium salt of EDTA (Protects Freshness)

Used in soft drinks containing ascorbic acid and sodium benzoate to mitigate the formation of benzene.

http://www.inchem.org/documents/jecfa/jecmono/40abcj09.htm

Pyridoxine Hydrochloride (Vitamin B6)

See http://www.geekhealth.org/post/2010/01/27/B-Vitamins-and-Weight-Loss.aspx

Yellow #5

This is known by the chemical name Tartrazine and is a highly debated food additive.  Some medical studies have shown the ingestion of this chemical and contribute to irritability and restlessness as well as hyperactivity.

Yellow #6

Like Yellow #5 and most other food coloring additives in general, there is a good deal of debate on the health impact of ingesting Yellow #6.  A good article to check out on the potential problems with Yellow #6 and other additives can be found here.

Cyanocobalamin (Vitamin B12)

See http://www.geekhealth.org/post/2010/01/27/B-Vitamins-and-Weight-Loss.aspx