How does your body metabolise alcohol?
Mostly in your liver, about 1 unit an hour. But the first step turns alcohol into a chemical that can damage your cells. Some people clear that chemical far more slowly than others.
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How does your body metabolise alcohol?
Your liver does most of the work. About 90% of the alcohol you drink is broken down, mostly in the liver. Less than 10% leaves in your breath, sweat and pee.
Your body can’t store alcohol. The NHS says the average adult clears about 1 unit an hour, though this varies from person to person.
How your liver breaks alcohol down
- 1
Into your blood
Alcohol passes from your stomach and gut into your blood.
- 2
Liver, step one
An enzyme (a helper chemical) called ADH turns alcohol into acetaldehyde.
- 3
Liver, step two
A second enzyme, ALDH, turns acetaldehyde into acetate.
- 4
Round the body
Acetate travels on and is turned into the same fuel your body makes from food.
Source: Cederbaum, Clin Liver Dis 2012
That harmful middle step is acetaldehyde. Cancer Research UK says it can damage your cells and stop them repairing the damage.
Think of your liver as a sink that drains at a steady speed. Pour in faster than it drains and the level rises. The NHS says alcohol poisoning can happen when you drink quicker than your body can process it.
So the number to know is how many units you’ve had. Count yours with our alcohol units guide.
How long does it take to process alcohol?
Roughly an hour for each unit, for the average adult. The more units, the more hours.
| Drink | Units | Rough hours to clear |
|---|---|---|
| Single 25 ml shot of spirits (40%) | 1 | About 1 |
| Pint of lower-strength beer or cider (3.6%) | 2 | About 2 |
| Standard 175 ml glass of wine (12%) | 2.1 | About 2 |
| Pint of higher-strength beer or cider (5.2%) | 3 | About 3 |
| Large 250 ml glass of wine (12%) | 3 | About 3 |
| 750 ml bottle of wine (13.5%) | 10 | About 10 |
Source: NHS
Drank a whole bottle of wine? That’s about 10 hours of work for the average liver. Some alcohol may still be in your blood the next morning.
Driving the next day? GOV.UK says it’s impossible to say exactly how many drinks put you over the limit. It’s different for each person.
So treat these hours as a rough guide, never a safe time to drive.
Blood test coming up? See how long to skip alcohol before a blood test.
Can you speed up alcohol metabolism?
Not much. Food is the one thing that helps. For someone with alcohol poisoning, the NHS says don’t give coffee or a cold shower.
Coffee can dehydrate them. A cold shower risks them getting too cold, falling or passing out.
Cancer Research UK says hangover cures don’t reverse the damage from drinking.
Food does help. A meal slows how fast alcohol gets into your blood, and the liver clears it faster after eating than when you’ve fasted.
Ways to give your liver less to clear
- Eat something and drink a glass of water before you have alcohol.
- Swap every other alcoholic drink for water or a soft drink.
- Pick a smaller size, like a small glass of wine instead of a large one.
- Choose lower-strength drinks. Check the alcohol % on the label.
- Have several drink-free days each week.
- Keep to 14 units a week or less, spread over 3 or more days.
Sources: NHS: tips on cutting down; NHS: alcohol units
Thinking of a break? See what happens when you give up alcohol.
Why does alcohol affect some people more?
GOV.UK lists your weight, age, sex, metabolism, what you drink and eat, and stress.
Women tend to reach a higher peak blood alcohol than men on the same dose per kilo of body weight. The stomach also breaks down a little alcohol first, and this may be greater in men.
Go red after one drink? Some people have a slow form of ALDH, the enzyme that clears acetaldehyde. It’s found in 15 to 40% of people in East Asia.
After drinking, their acetaldehyde levels are 5 to 20 times higher. Their face goes red and they can feel sick.
If you flush every time, your body may be holding on to more of the chemical that can damage cells. Drinking less is the simple next step.
When to speak to a GP
Liver damage from alcohol does not always cause symptoms early on. If you stop drinking, your liver can often recover.
- Call 999 if you think someone has alcohol poisoning, has had a fit, has passed out or has stopped breathing. Signs include confusion, slurred speech, being unable to stand or walk, being sick, wetting or soiling themselves, pale or blue-tinged skin, and slow or irregular breathing. See the NHS alcohol poisoning page.
- Call 999 or go to A&E if you’re worried about your liver and you vomit blood or have black, sticky poo. The same goes for tummy pain, trouble breathing, or feeling suddenly confused, dizzy or hard to keep awake.
- See a GP if you have signs of liver disease. These include feeling very tired, less hungry, losing weight without trying, feeling or being sick, or pain or discomfort in the upper right of your tummy.
- See a GP or an alcohol support service if you’re worried about your drinking or want help to stop.
Your GP may check your liver with a blood test. See what a liver function test shows.