• Metabolism

Over 90 per cent of alcohol consumed is eliminated from the body via the liver, with approximately two to five per cent being excreted unchanged in sweat, breath and urine. The initial process of metabolism is oxidation by enzymes known as alcohol dehydrogenases. This produces acetaldehyde €“ a highly reactive and toxic substance that is harmful to the liver, brain and stomach and is responsible for hangover symptoms. In healthy people, acetaldehyde is rapidly broken down further to acetate, and then to carbon dioxide and water, via both the liver and peripheral tissues.

• Elimination

Blood alcohol levels tend to peak one hour after drinking. Following consumption of one alcohol unit, the levels in the bloodstream decline in a more or less linear fashion for the next four hours. The alcohol elimination rate from the blood is approximately one unit per hour for an average sized man, but is variable dependent on a number of factors, including the amount consumed.