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Alcohol

Follow one dose of alcohol from the moment it enters the body until the last of it leaves.

EthanolactiveAcetaldehydetoxic carcinogen, via ADHAcetatenon-toxic, via ALDHCO₂ + water

The clock

Alcohol has no fixed half-life. The liver clears it at a roughly constant rate, about 8 grams of pure alcohol (one UK unit) an hour.

  1. 0 mindrink

    Some is broken down before it reaches the blood

    stomach and gut

    Some alcohol is metabolised in the stomach and small intestine before it ever enters the bloodstream.1

  2. minutesliver

    Ethanol → acetaldehyde

    alcohol dehydrogenase (ADH)CYP2E1 at high levelsacetaldehyde is toxic

    Alcohol dehydrogenase turns ethanol into acetaldehyde, a toxic carcinogen.1 CYP2E1 mostly works at higher concentrations, and regular heavy drinking increases its activity.1

  3. minutesliver

    Acetaldehyde → acetate

    ALDHacetate is non-toxic

    Aldehyde dehydrogenase turns acetaldehyde into the non-toxic acetate ion.1

    Genes: people with impaired aldehyde dehydrogenase get higher acetaldehyde peaks and worse hangovers.1
  4. ~1 unit / hourconstant rate

    Acetate → carbon dioxide and water

    ~8 g pure alcohol per hour

    Acetate is broken down into carbon dioxide and water.1 The body removes alcohol at a roughly constant rate, very roughly 8 grams of pure ethanol an hour.1

    You can't speed this up: because the rate is roughly fixed, drinks taken faster than about one unit an hour stack up in the blood. TripSit rates alcohol with opioids or benzodiazepines as Dangerous and with cocaine as Unsafe.2 Alcohol with cocaine also makes cocaethylene (see the cocaine timeline).
  5. throughoutexit

    A little leaves unchanged

    breathurinesweat

    About 5 to 10% of the alcohol a person drinks leaves unchanged in urine, breath and sweat.1

Sources

  1. Wikipedia, Ethanol metabolism, CC BY-SA
  2. TripSit combination chart (combos.json, read 2026-10-24)

Half-lives vary between people, doses and routes. This page explains what the body does with a drug. It is not dosing advice.