What a Hangover Is, and Is Not

Key takeaway

NIAAA says a hangover is the next-day symptoms of drinking too much, peaking when blood alcohol returns to about zero, and lasting 24 hours or longer. There is no proven cure except time. Coffee, a shower, and a morning drink do not fix it. Alcohol overdose and withdrawal are different emergencies. Call 911 for those.

Last updated: Mon Oct 05 2026 00:00:00 GMT+0000 (Coordinated Universal Time)

You feel wrecked, and you are trying to tell a bad morning from something that needs an ambulance. A hangover is the illness that shows up after drinking too much, not the emergency in which someone will not wake. NIAAA's fact sheet, updated December 2025, defines it as a set of symptoms that follow drinking too much. The typical list includes fatigue, weakness, thirst, headache, muscle aches, nausea, stomach pain, vertigo, sensitivity to light and sound, anxiety, irritability, sweating, and increased blood pressure. People do not get the same mix. NIAAA says it is hard to predict how many drinks will cause one, because people differ. Any time someone drinks to intoxication, a hangover is possible the next day.

Symptoms peak when blood alcohol concentration falls back to about zero. They can last 24 hours or longer. That is why the worst hour can arrive after the person no longer feels drunk. During that stretch, NIAAA says attention, decision-making, and muscle coordination can all be impaired. Driving, running machinery, or being the only person caring for someone else can go badly.

Alcohol overdose, including confusion, not waking, very slow breathing, and seizures, is the blackout guide. Do not wait until every sign is present, and do not try to cure an overdose with coffee or a cold shower. What can happen when someone who has been drinking heavily for a long time stops, including seizures, is the withdrawal guide. A bad morning is not the way to tell those three problems apart. If you are unsure, call 911. For a mental health crisis, call or text 988.

What NIAAA says is going on in the body

Alcohol is the main cause. Other parts of the drink can add to it. Congeners are compounds, besides ethyl alcohol, made during fermentation. They affect taste and smell. NIAAA says darker spirits such as bourbon, which tend to have more congeners than clear spirits, could worsen hangover symptoms for some people. That is not a finding that clear liquor is safe. Sulfites are preservatives added to wine. People who are sensitive to them may get a headache after wine. Most people with a hangover are not having a sulfite allergy. They drank alcohol.

NIAAA names several contributors:

Mild dehydration. Alcohol suppresses vasopressin, a brain hormone that tells the kidneys to hold fluid. Urine output goes up, fluid is lost, and the mild dehydration that follows likely adds to thirst, fatigue, and headache.
Broken sleep. People may fall asleep faster after drinking, then sleep in fragments and wake earlier. That adds to fatigue and to lost time the next day.
Stomach irritation. Alcohol irritates the stomach lining and increases acid. Nausea and stomach pain can follow.
Inflammation. Alcohol increases inflammation. NIAAA says inflammation contributes to the wiped-out feeling of being sick, so it may play a role in hangover symptoms.
Acetaldehyde. The liver's metabolism of alcohol produces this toxic, short-lived compound, which contributes to inflammation in the liver, pancreas, brain, gut, and other organs.
What the sheet calls mini-withdrawal. While drinking, a person may feel calm or euphoric. The brain adjusts. When the effect wears off, the person can feel more restless and anxious than before the drink.

Read that last item narrowly. It is NIAAA's account of rebound restlessness as a buzz fades. It is not delirium tremens, and it is not a schedule for quitting. If drinking has been heavy and prolonged, stopping can be medically dangerous. Do not use a hangover as the moment to white-knuckle a stop. The placement question is the detox guide. Get emergency help for a seizure, collapse, trouble breathing, or severe confusion.

Myths the fact sheet rejects

NIAAA pairs common claims with a correction.

Drinking coffee or taking a shower does not prevent or cure a hangover. The only complete avoidance NIAAA states is not drinking, or keeping alcohol intake to a minimum. There is no cure other than time.

The order of drinks does not matter in the way the rhyme claims. In general, the more alcohol a person drinks, the worse the hangover, whether the alcohol was beer, wine, distilled spirits, or a mix. NIAAA's blood-alcohol definition and the meaning of a standard drink are explained on the binge guide. A large pour can be more than one standard drink. The fact sheet does not print a number of drinks that is safe from a hangover.

A morning drink can briefly take the edge off some symptoms. NIAAA says it can also contribute to the hangover and make it last longer. That practice is not a treatment. If morning drinking is how the day starts, that belongs in a conversation with a clinician, not on a remedy list.

Pain relievers, electrolytes, and the liver

NIAAA says none of the remedies promoted online have been shown to work. The body has to clear the toxic byproducts, rehydrate, heal irritated tissue, and restore immune and brain activity. Nothing on the sheet speeds the brain's recovery. Coffee, a shower, and another drink do not.

Some people take an over-the-counter pain reliever, often acetaminophen, before bed. NIAAA's warning is direct: alcohol and acetaminophen together can be toxic to the liver. Aspirin and ibuprofen, like alcohol, can increase acid and irritate the stomach. Use caution with those medicines before or after drinking. Alcohol-associated liver disease, a different and more serious problem than one morning of nausea, is the liver guide. The wider list of medicines that clash with alcohol is the older-adult guide. Do not build a new combination from a fact sheet.

Sports drinks and IV electrolyte treatments are aimed at fluid loss. NIAAA says research has not found a correlation between how far electrolytes are disrupted and how bad the hangover is, or an effect of added electrolytes on severity. In most people, balance returns once the alcohol effect subsides. An IV lounge is not the cure the fact sheet says is missing.

The sheet's own bottom line is avoidance: drink less, or do not drink. It does not print a personal limit. People who are pregnant, who take interacting medicines, who are in recovery, or who cannot control the amount should not treat a hangover note as permission for a smaller amount. Drinking that does not look like a stereotype and can still be a problem is the gray-area guide. Treatment, including medicines a clinician may use after withdrawal is handled, is the alcohol page. Those medicines do not cure a hangover, and they do not belong in a morning experiment.

When the morning is not a hangover

If someone is unconscious, seizing, breathing slowly, or vomiting and cannot be woken, that is the emergency already named above. Do not leave the person alone. Do not put them in a cold shower.

If stopping after heavy drinking brings shaking that is severe, confusion, or a seizure, treat that as withdrawal until a clinician says otherwise. Get emergency help.

Anxiety and irritability are on the hangover list. Thoughts of suicide are not a symptom to wait out. Use the crisis line above.

FindTreatment.gov lists programs. SmarterRecovery is a referral helpline. SMART Recovery is a separate mutual-help program. Call or text (800) 653-9376 if you want help finding an alcohol assessment.

Additional Resources

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Common Questions

What symptoms does NIAAA include in a hangover?

Its fact sheet, updated December 2025, lists fatigue, weakness, thirst, headache, muscle aches, nausea, stomach pain, vertigo, sensitivity to light and sound, anxiety, irritability, sweating, and increased blood pressure. A hangover can differ from person to person. NIAAA says it is hard to predict how many drinks will cause one. Any time someone drinks to intoxication, a hangover is possible the next day.

When does it peak, and how long can it last?

NIAAA says symptoms peak when blood alcohol concentration returns to about zero. They can last 24 hours or longer. That timing is why someone can feel worst after the alcohol is already gone. It is not a reason to drive, operate machinery, or be the only adult watching a child. NIAAA says attention, decision-making, and muscle coordination can all be impaired during a hangover.

Do coffee, a shower, or another drink in the morning cure it?

No. NIAAA says the only way to avoid a hangover completely is not to drink, or to keep drinking to a minimum, and that there is no cure other than time. Coffee and a shower do not prevent or cure it. A morning drink, sometimes called a hair of the dog, might briefly ease some symptoms and can also prolong the misery. The order of beer, wine, and liquor does not decide the hangover. In general, more alcohol means a worse hangover, whatever was in the glass.

Is a hangover the same as alcohol poisoning or withdrawal?

No. A hangover is the next-day illness NIAAA describes on that fact sheet. Alcohol overdose is the emergency in which someone may not wake, may breathe too slowly, or may seize. The blackout guide lists those signs. Call 911 and do not wait for every sign. Withdrawal after prolonged heavy drinking can be life-threatening and can include seizures. The withdrawal guide is that warning. NIAAA's phrase mini-withdrawal on the hangover sheet means feeling restless and anxious as the pleasant effects wear off. It is not delirium tremens, and it is not permission to detox at home.

Can I take acetaminophen before bed so I do not feel it tomorrow?

NIAAA says some people do that, and that alcohol plus acetaminophen can be toxic to the liver. Aspirin and ibuprofen can increase stomach acid and irritate the stomach lining, which alcohol also does. Electrolyte drinks and IV treatments are popular. NIAAA says research has not found that the size of an electrolyte shift matches hangover severity, or that adding electrolytes reduces it. In most people the body restores the balance once the alcohol effect fades. There is no proven remedy on that sheet except time.