Why does alcohol make you pee more?

Ever wondered why you need to pee so much when you’ve been drinking?

You don't need to be a scientist to see the toilet queues on a Saturday night or at an event to make the link between drinking alcohol and the need to pee. So why exactly does drinking alcohol make us need to pee more than when we drink soft drinks or water?

The science

“Alcohol is a diuretic,” says Professor Oliver James, head of clinical medical sciences at Newcastle University. “It acts on the kidneys to make you pee out much more than you take in – which is why you need to go to the toilet so often when you drink.” In fact for every 1g of alcohol drunk, urine excretion increases by 10ml.(1)

Alcohol also reduces the production of a hormone called vasopressin, which tells your kidneys to reabsorb water rather than flush it out through the bladder. With the body's natural signal switched off the bladder is free to fill up with fluid.

Dashes to the toilet

A common side effect of drinking is needing the toilet just five minutes after your last visit. This irritating experience (usually known as 'breaking the seal') happens because alcohol delivers a hefty double whammy to your kidneys.

"Suppose you have a pint at lunchtime," explains Oliver James. "At some point you'll need to go to the toilet and get rid of the pint of liquid you've just drunk. Then an hour later you'll have to pee again because of the added diuretic effect."

Alcoholic drinks with less volume won’t stop the need to pee!

Switching to alcoholic drinks with less volume such as shots won't stem the flow either, since whether you're drinking pints or doing shots, it's the diuretic element of the alcohol which is key to producing all that wee.

So does weeing all the alcohol out of my system help prevent a hangover?

Unfortunately not.  Because alcohol promotes peeing, it can lead to dehydration, which causes the nausea and headache associated with bad hangovers. It's also why your mouth might feel like the driest place on earth the next day.

Want to learn more about your hangovers?

Find time for water when drinking alcohol

With fluid leaving your body so quickly, dehydration can be a big problem. Though it might seem like even more liquid is the last thing you need when you’re regularly having to dash to the gents/ladies, regular sips of water during and after drinking are what you need to keep yourself hydrated.

Another way to avoid dehydration from alcohol is to stay within the lower risk guidelines. Use our unit calculator to see what the guidelines look like in terms of drinks.

Are you drinking too much?

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Effects of drinking too much

Over-consumption of alcohol can affect your health in many ways.

Health effects of alcohol Effects on relationships The effects of alcohol on your child


Page updated: March 2015