Everyone has a hangover cure they swear by, a fry-up, a pint of water, a coffee, or the infamous hair of the dog. The uncomfortable truth is that the science is far less generous than the folklore. There is no proven cure for a hangover, only time and a handful of things that genuinely take the edge off. This guide sorts what actually works from what does not, explains why you feel so rough in the first place, shows which drinks do the most damage, and gives you the one painkiller you should never reach for. Everything here is sourced.
1. What actually causes a hangover
A hangover is not one thing going wrong, it is several at once. Alcohol is the main culprit, but the misery comes from a stack of effects that peak just as your blood alcohol returns to zero[1]. Here is what is actually happening the morning after.
- Dehydration. Alcohol suppresses vasopressin, the hormone that tells your kidneys to hold on to water, so you urinate more and lose fluid. That drives the thirst, fatigue and headache[1] (more on whether beer actually hydrates you here).
- Acetaldehyde. As your liver breaks alcohol down it produces acetaldehyde, a toxic short-lived byproduct that causes inflammation in the liver, gut, brain and elsewhere[1].
- Congeners. These are flavour compounds made during fermentation and ageing. Darker drinks like bourbon and red wine carry far more of them, and they make hangovers measurably worse[1][2].
- Wrecked sleep. Alcohol cuts sleep efficiency and slashes REM sleep, so you wake unrested even after a full night[2].
- Low blood sugar and an irritated stomach. Alcohol disturbs blood glucose and inflames the stomach lining, adding shakiness and nausea[1].
- An immune and inflammatory response. Your body treats a heavy session as an insult and mounts an inflammatory reaction linked to the poor mood and brain fog[1].
The practical takeaway: because so many systems are involved, no single pill or potion can switch a hangover off. That is exactly why the cure list is so short.
2. How long a hangover lasts
A hangover typically starts as your blood alcohol drops toward zero, often overnight, and can last up to 24 hours[4]. There is no way to speed your liver up: it clears roughly one unit of alcohol per hour, and no amount of coffee, cold showers or greasy food changes that rate. If you drank heavily late, do the maths, the alcohol itself may still be leaving your system well into the next morning, which is why you can still be over the drink-drive limit at breakfast.
3. What actually helps, and what does not
A landmark systematic review in the BMJ looked at every trial of hangover treatments it could find and reached a blunt conclusion: no conventional or complementary remedy has compelling evidence behind it[3]. So the honest advice is about relief, not cure. Here is the evidence-led verdict on the popular fixes.
| Remedy ↕ | Verdict ↕ | What the evidence says ↕ |
|---|---|---|
| Time | WORKS | The only sure fix. Symptoms fade as your body recovers, usually within a day. |
| Water and electrolytes | HELPS | Will not cure it, but rehydrating eases the thirst, fatigue and headache from fluid loss. |
| Bland food (toast, crackers) | HELPS | Gently restores blood sugar and settles the stomach; bouillon replaces lost salt and potassium. |
| Sleep and rest | HELPS | Alcohol ruins sleep quality, so catching up helps you recover (see why beer makes you sleepy in the first place). |
| Ibuprofen / aspirin | CAUTION | Can ease the headache but both irritate an already raw stomach; use sparingly, with food. |
| Coffee | MIXED | May lift alertness but is a mild diuretic, so it does nothing for dehydration. |
| Greasy fry-up (after) | MYTH | Best eaten before drinking, not after. The morning after it just burdens a delicate stomach. |
| Vitamins and ‘cure’ supplements | UNPROVEN | No supplement has strong trial evidence; a few show only minor, inconsistent effects. |
| Hair of the dog | MYTH | Postpones symptoms at best and prolongs the misery; see below. |
Tap any column heading to sort.
Evidence-led verdict on common hangover remedies. Sources: BMJ systematic review; Mayo Clinic; NIAAA.
4. Does hair of the dog work?
Hair of the dog, having another drink the morning after, is the oldest folk remedy there is. The name comes from a medieval belief that a dog bite could be healed by placing a hair from the same dog on the wound. As hangover science, it does not hold up.
There is a sliver of real chemistry behind it: alcohol competes with the breakdown of methanol, a minor congener, so topping up your ethanol can briefly delay some of the nastier byproducts forming. But that is a postponement, not a cure. The moment you stop, the hangover returns, now layered on top of a fresh dose of alcohol[1]. As the NIAAA puts it plainly, another morning drink might temporarily mask symptoms but can prolong the malaise and simply digs the hole deeper. Leaning on it regularly is also a recognised warning sign of alcohol dependence. Skip it.
5. Which drinks give the worst hangovers
Not all drinks are equal, and the difference is mostly congeners. In a controlled study, people who drank bourbon reported a significantly worse hangover than those who drank the same amount of vodka, because bourbon contains about 37 times more congeners[2]. As a rough guide, the clearer and lighter the drink, the fewer congeners and the gentler the morning. That same congener gap also explains why some beers give you a worse hangover than others. (If you are comparing a round of shots to a round of beers, see how much alcohol each actually contains.)
Relative congener content by drink type, illustrative ordering. Bourbon has about 37x the congeners of vodka; exact levels vary by brand and batch. Source: Rohsenow et al (2010), citing Nathan et al.
Good news for beer drinkers: beer sits at the lower end, well below dark spirits and red wine. The old rule of thumb holds, clear and pale drinks are kinder the next day. And the amount still matters more than anything, since a big night on vodka will beat a single dark ale every time. If you want the wider numbers on beer strength and how alcohol is measured, our beer statistics page has the full picture, and our beer colour guide explains why darker is not the same as stronger. And if you like a shot with your pint, our guide to the boilermaker and mixing beer with spirits covers what that really does to you. Poor sleep is a big part of why hangovers feel so bad, and our beer and sleep guide explains the connection.
6. How to prevent a hangover
Prevention beats every cure, because it is the only thing that actually works. None of these are magic, but stacked together they make a real difference[4].
- Pace yourself. Stay near or below one unit an hour so your liver keeps up and your peak blood alcohol stays lower.
- Drink water alongside. A glass of water between drinks offsets the fluid you are losing and naturally slows you down.
- Eat before and during. Food, especially before you start, slows alcohol absorption and steadies blood sugar.
- Choose lighter-coloured drinks. Fewer congeners means a gentler morning, so a pale lager or a vodka soda beats bourbon or red wine.
- Know your limit and stop while ahead. The dose makes the hangover; the less you drink, the less there is to recover from.
- Do not bother with drink order. The old “beer before wine” saying does not hold up, a randomized controlled trial found no effect from switching drink order, only total amount matters. The same logic holds even when you only drink beer all night, switching between beer styles does not make a hangover worse on its own either.
- Does Altitude Change How Drunk You Get?
And if none of that happens and you wake up regretting it anyway, the plan is simple: water, a bland snack, a careful painkiller if you need one, and patience. Time is doing the real work.
7. Frequently asked questions
What is the best cure for a hangover?
There is no proven cure. Time is the only sure fix, and symptoms can last up to 24 hours. The best you can do is ease them by rehydrating with water and electrolytes, eating bland food to steady blood sugar, resting, and being cautious with painkillers.
Does drinking water cure a hangover?
It helps but does not cure. Alcohol dehydrates you by suppressing the hormone vasopressin, so replacing fluids eases the thirst, fatigue and headache. It does nothing about the acetaldehyde, poor sleep and inflammation also driving the hangover, so water alone will not fix everything.
Does hair of the dog actually work?
No. Having another drink the next morning can briefly mask symptoms because alcohol delays some toxic byproducts forming, but it only postpones the hangover and prolongs the misery. Relying on it regularly is also a warning sign of alcohol dependence.
Which alcohol gives the worst hangover?
Dark drinks high in congeners, such as bourbon, brandy, whisky and red wine. In one study, bourbon caused a significantly worse hangover than vodka because it has about 37 times more congeners. Clear, pale drinks like vodka, gin and lager are gentler, though the total amount you drink matters most.
What painkiller should you avoid with a hangover?
Paracetamol, also sold as acetaminophen, Tylenol or Panadol. Combining it with alcohol still in your system can cause serious liver damage. A cautious dose of ibuprofen or aspirin with food is safer, but both can irritate the stomach.
How long does a hangover last?
Usually up to 24 hours. It tends to start as your blood alcohol falls toward zero, often overnight, and fades through the next day. Your liver clears only about one unit of alcohol per hour and that cannot be rushed.
Does eating a big breakfast cure a hangover?
Not really, and timing matters. Eating before you drink slows alcohol absorption and helps prevent a hangover. The morning after, a greasy fry-up mostly burdens an irritated stomach; bland food like toast or crackers is gentler and helps restore blood sugar.
Do hangover cure pills and supplements work?
There is no strong evidence for any of them. A BMJ review of hangover treatments found no compelling proof that any conventional or herbal remedy prevents or cures a hangover, with only a few showing minor, inconsistent effects.
Sources and references
- National Institute on Alcohol Abuse and Alcoholism (NIAAA), Hangovers fact sheet
- Rohsenow et al (2010), Intoxication with Bourbon versus Vodka: Effects on Hangover, Sleep and Next-Day Performance
- Pittler, Verster and Ernst, BMJ (2005), Interventions for preventing or treating alcohol hangover: systematic review
- Mayo Clinic, Hangovers: Diagnosis and treatment
- US Food and Drug Administration, Acetaminophen and liver damage warning
This article is general information, not medical advice. If you are worried about your drinking or a severe reaction, speak to a healthcare professional. Please drink responsibly. Reviewed August 2026.
