A typical hangover lasts roughly 12 to 24 hours, though some people feel off for up to 72 hours after heavy drinking. Symptoms begin as your blood alcohol level drops toward zero, peak in the morning hours after a night of drinking, and gradually fade over the course of the day. How quickly you bounce back depends on how much you drank, what you drank, how well you slept, and your individual biology.
When Symptoms Start and Peak
Hangover symptoms don’t hit while you’re still drunk. There is scientific consensus that a hangover begins when your body has fully metabolized the ethanol in your system and your blood alcohol concentration approaches zero. For most people who stop drinking late at night, that means symptoms emerge in the early morning hours and peak sometime before midday.
The timing creates a counterintuitive pattern: the slower your body clears alcohol in the first few hours after drinking, the more ethanol remains in your system into the second half of the night and early morning. That lingering alcohol triggers more oxidative stress and a stronger inflammatory response, which is why the worst hangovers often come from nights where you drank heavily right up until going to sleep.
What’s Actually Happening in Your Body
A hangover is fundamentally an inflammatory event. When your liver breaks down alcohol, the process generates reactive molecules that overwhelm your body’s antioxidant defenses. Those molecules form compounds your immune system treats as foreign invaders, triggering an immune response that floods your bloodstream with inflammatory signals. Research published in the Journal of Clinical Medicine found that hangover severity correlates directly with blood levels of key inflammation markers, particularly one called IL-6. Even four hours after drinking, ethanol itself was still driving elevated inflammatory signals, suggesting the damage isn’t just from alcohol’s breakdown products.
This inflammation is what makes you feel terrible. It contributes to headache, nausea, body aches, and that general sense of malaise. Your stomach lining is irritated, your sleep has been disrupted, and your body is dehydrated from alcohol’s diuretic effect. All of these processes need time to resolve, which is why there’s no real shortcut to recovery.
Why Some Hangovers Last Days
Most hangovers resolve within 24 hours, but a recovery period stretching to two or three days isn’t unusual after particularly heavy drinking. According to Dr. Stephen Harding at Baylor College of Medicine, the body needs time to eliminate all the byproducts, rehydrate, and recover from the inflammation. That process can take a few days before you feel fully normal.
What you drank matters too. Darker alcohols like bourbon, red wine, and brandy contain higher levels of congeners, which are small molecules that give drinks their flavor, color, and aroma but also amplify the inflammatory response. The general rule: the darker the drink, the worse the hangover. Clear spirits like vodka and gin have fewer congeners and tend to produce milder aftereffects at equivalent alcohol amounts.
How Sleep Quality Changes Recovery Time
One of the strongest predictors of how long your hangover lasts is how well you slept. Alcohol fragments your sleep in measurable ways: it reduces sleep efficiency, cuts into REM sleep (the deep, restorative stage), and increases the amount of time you spend awake during the night. A large study published in Nature and Science of Sleep found that total sleep time was significantly correlated with both hangover severity and hangover duration. People who got less sleep reported worse hangovers that dragged on longer.
The connection was especially strong for fatigue and sleepiness, which makes sense. If alcohol has already disrupted the quality of your rest, you’re starting the next day in a deficit. This is one area where you have some control: sleeping in, napping, or simply resting can meaningfully shorten how long you feel rough.
Age, Genetics, and Individual Variation
You might assume hangovers get worse with age, but research tells a more complicated story. A large study examining hangovers across the lifespan found that hangover severity, subjective intoxication, and hangover frequency all decline with age after correcting for how much people actually drank. The likely explanations include increased alcohol tolerance over time and a gradual, well-documented decline in pain sensitivity as people get older. So if your hangovers feel worse than your older coworker’s, it may not be because your body is less resilient. It may be that they’ve developed tolerance and simply perceive the discomfort less intensely.
Genetics also play a role, though a modest one. Variants in the genes that code for alcohol-processing enzymes account for roughly 2.5 to 9.5 percent of the variation in hangover sensitivity between people. The most notable genetic factor involves enzyme variants common in East Asian populations that cause facial flushing after drinking. People with these variants tend to experience more severe hangovers because their bodies are slower to clear acetaldehyde, one of alcohol’s most toxic breakdown products.
What Actually Helps You Recover Faster
No pill, supplement, or “hangover cure” has been proven to meaningfully shorten recovery time. What does help is addressing the specific things your body is dealing with: dehydration, inflammation, low blood sugar, and poor sleep.
- Water and electrolytes. Alcohol suppresses the hormone that tells your kidneys to retain water, so you lose more fluid than you take in. Drinking water or an electrolyte solution helps restore balance and can ease headache and dizziness.
- Food. Eating bland, easy-to-digest food helps stabilize blood sugar and settle your stomach. Toast, crackers, bananas, and broth are reliable options.
- Sleep and rest. Given the direct link between sleep time and hangover duration, additional rest is one of the most effective things you can do.
- Time. Your liver processes alcohol at a fixed rate, and the inflammatory cascade needs to run its course. Most of recovery is simply waiting.
Over-the-counter pain relievers can help with headache, but be cautious with anything containing acetaminophen if there’s still alcohol in your system, as the combination is hard on your liver. Anti-inflammatory options are gentler in that regard but can further irritate an already-upset stomach.
A Rough Timeline
For a moderate night of drinking (four to six drinks), most people feel noticeably better by the afternoon and essentially normal by evening, putting the total hangover at roughly 12 to 16 hours. For a heavier session, expect the worst symptoms to persist through the full next day, with lingering fatigue and brain fog potentially stretching into the following morning. After an unusually heavy binge, it can take two to three days for energy, mood, and digestion to fully return to baseline. The single biggest factor in that timeline is simply how much you drank, since everything else flows from the total amount of alcohol your body has to process and recover from.