This article was taken from the October 2012 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.

Every month Wired's chemist Dr John Emsley deconstructs an everyday product. He is the author of 110 research papers and 12 books, including Nature's Building Blocks, 2nd edition (OUP).

<span class="s1">Ingredients -Caffeine


-Citric acid

-Malic acid

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-Sweeteners

-Niacin


-Phenylalanine

-Preservatives

-Glucuronolactone

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-Taurine


-Vitamin B6

-Vitamin B12

Caffeine

Aids stored-energy release in the body and stimulates the brain by increasing dopamine levels.

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Malic acid

The acid of unripe apples, here it acts as an antioxidant. Malic acid is used to clean teeth before filling.

Niacin

This aids enzymes in releasing energy from carbohydrates.

Fish, poultry and nuts also contain lots of niacin.

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Citric acid

Often added to fizzy drinks for its fruity tang, it is also used in household cleaners to remove limescale.

<span class="s1">Sweeteners

There are three kinds here: sucralose (E955), acesulfame potassium (E950) and aspartame (E951).

Phenylalanine

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An essential amino acid that cannot be produced by the body, and comes only from the food that we eat.

Preservatives

Potassium sorbate occurs naturally in rowan berries. Sodium benzoate is found in cranberries.

<span class="s1">Glucuronolactone

Made from glucose by the liver, it is used by the body's connective tissues. It is also reputed to improve mental alertness.

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Taurine

Its role here is to improve muscle tone. It can be extracted from shark blood, but is usually synthesised.

Vitamin B6


Converts amino acids into enzymes and muscle protein. It also aids energy release from carbohydrates.

Vitamin B12

Found in meat and eggs, it is used in red blood cell production and in the functioning <span class="s3">of the nervous system.