Most hangovers last roughly 12 to 24 hours, though a particularly heavy night of drinking can stretch symptoms beyond that. Hangover symptoms peak once your blood alcohol level drops back to zero, which for many people happens the morning after drinking. From that peak, you’re typically on a slow climb back to normal over the course of the day.
How quickly you recover depends on how much you drank, what you drank, whether you ate, how well you slept, and your individual biology. Here’s what’s actually happening inside your body during a hangover and what you can realistically do to speed things along.
How Your Body Processes Alcohol
Your liver clears alcohol at a relatively fixed rate: about one standard drink per hour for an average-sized adult (around 7 grams of ethanol per hour). That rate doesn’t change much regardless of what you do. Coffee, cold showers, and “sweating it out” don’t speed up your liver.
So if you had eight drinks over the course of an evening, your body needs roughly eight hours just to clear the alcohol itself. But the hangover doesn’t end when the alcohol is gone. It’s actually just getting started. Your worst symptoms hit right around the time your blood alcohol reaches zero, because by then the damage from the drinking session is fully in play: inflammation, dehydration, disrupted sleep, and low blood sugar are all peaking simultaneously.
What’s Causing Each Symptom
A hangover isn’t one problem. It’s several overlapping ones, each with its own recovery timeline.
Inflammation. Drinking triggers your immune system. Research on healthy subjects found that key inflammatory signaling molecules were significantly elevated 13 hours after drinking, at the point when blood alcohol had returned to zero. This immune activation is a major driver of that general feeling of being unwell, the brain fog, and the body aches. It’s also why a hangover can feel similar to coming down with a mild illness.
Dehydration and electrolyte loss. Alcohol is a diuretic, meaning it makes you urinate more than the volume of fluid you’re taking in. By morning, you’re often dehydrated and low on electrolytes like sodium and potassium. Once you stop drinking, your body works to correct the electrolyte imbalance, but full rebalancing can take several days for heavier episodes. In practice, mild to moderate dehydration from a single night out typically resolves within a day with adequate fluid intake.
Low blood sugar. Your liver prioritizes breaking down alcohol over its other job of regulating blood sugar. While it’s busy processing ethanol, it releases less stored glucose into your bloodstream. The result is a dip in blood sugar that contributes to fatigue, shakiness, and difficulty concentrating. Eating a proper meal helps more than sugary drinks here, because solid food digests gradually and provides a steadier supply of glucose.
Poor sleep quality. Even if you slept for eight hours after drinking, much of that sleep was low quality. Alcohol suppresses REM sleep, the restorative phase your brain needs most. Later in the night, as alcohol wears off, you often get a “REM rebound” that fragments your sleep with vivid dreams and frequent waking. This disrupted sleep architecture is a big reason why you feel exhausted the next day even after a full night in bed.
Typical Recovery Timeline
For a moderate night of drinking (three to five drinks), most people feel noticeably better within 12 hours of waking. A heavy session (eight or more drinks) can push recovery to a full 24 hours, and occasionally longer. Here’s a rough progression:
- First few hours after waking: Peak misery. Headache, nausea, sensitivity to light and sound, fatigue, and thirst are all at their worst.
- 4 to 8 hours in: Nausea and headache usually begin to ease. Fatigue and brain fog tend to linger.
- 12 to 24 hours: Most physical symptoms have faded. You may still feel mentally sluggish or have trouble concentrating, partly because of residual sleep deprivation.
The NIAAA notes that hangover symptoms can last 24 hours or longer, so if you’re still feeling rough well into the next evening, that’s within the normal range for a heavy drinking episode.
Why Some Hangovers Last Longer
Several factors push recovery time in one direction or the other.
Amount consumed. This is the single biggest predictor. Research consistently shows a direct relationship between how high your blood alcohol concentration gets and how severe your hangover will be. More drinks means more metabolic work for your liver, more dehydration, more inflammation, and a longer timeline to clear it all.
Type of alcohol. Darker spirits like bourbon, red wine, and brandy contain higher levels of congeners, which are byproducts of fermentation. Studies comparing bourbon to vodka found that bourbon produced more severe hangover ratings, though the total amount of alcohol consumed still mattered far more than the type. Choosing lighter-colored drinks may take the edge off, but it won’t prevent a hangover if you drink heavily.
Age. Liver enzyme efficiency and your body’s ability to manage inflammation both decline with age. The same number of drinks that barely fazed you at 25 may produce a two-day hangover at 40.
Food intake. Drinking on an empty stomach means faster alcohol absorption, higher peak blood alcohol, and a worse hangover. Food in your stomach slows absorption and gives your liver more time to keep up.
Sleep. If your night was cut short on top of being disrupted by alcohol, the fatigue and cognitive symptoms compound. Getting extra sleep the next day is one of the few things that genuinely helps.
What Actually Helps Recovery
There is no proven hangover cure. Research reviews have found that most marketed remedies only address some symptoms while leaving others untouched. For example, certain anti-inflammatory pain relievers reduced headache and nausea severity in studies but had no effect on tiredness. Prickly pear extract helped with nausea, dry mouth, and appetite but didn’t touch headache, weakness, or dizziness. No single intervention has been shown to reliably shorten the overall duration of a hangover.
That said, you can address individual symptoms and give your body what it needs to do its job:
- Water and electrolytes: Rehydrating is essential, but it won’t cure the hangover on its own, because dehydration is only one piece of the puzzle. Sports drinks or broth can help replace lost sodium and potassium.
- Food: A meal with complex carbohydrates and some protein helps stabilize blood sugar. Toast, eggs, oatmeal, or bananas are all solid choices.
- Sleep: If you can, go back to bed. Your body missed out on quality REM sleep overnight, and additional rest is one of the most effective ways to reduce fatigue and mental fog.
- Pain relievers: Over-the-counter options can help with headache. Avoid acetaminophen (Tylenol), which puts additional strain on your already-busy liver.
- Time: Ultimately, your liver processes alcohol at a fixed rate and your immune system calms down on its own schedule. Most of recovery is simply waiting.
Hangover vs. Alcohol Withdrawal
A standard hangover resolves within 24 hours for most people. If your symptoms intensify rather than improve after 24 hours, or if you experience severe anxiety, trembling, hallucinations, or seizures, that may be alcohol withdrawal rather than a hangover. Withdrawal typically begins 6 to 24 hours after the last drink in people who have been drinking heavily and regularly, with symptoms peaking between 24 and 72 hours.
The key distinction is pattern: hangovers happen to anyone after a heavy night and steadily improve throughout the day. Withdrawal happens to people whose bodies have become physically dependent on alcohol, and symptoms escalate rather than fade. Withdrawal can be medically dangerous and requires professional attention.