Most hangovers last about 18 hours from the time you stop drinking, though the typical range falls between 14 and 23 hours. If you finished your last drink at midnight, you can expect to feel mostly normal somewhere between early afternoon and late evening the next day. In some cases, symptoms can stretch past 24 hours.
When Symptoms Peak and When They Fade
Hangover symptoms don’t hit hardest the moment you wake up. They actually build over time, peaking roughly 14 hours after your last drink. If you stopped drinking around midnight, that puts the worst of it at about 2 p.m. the next day. This timing catches many people off guard because they expect the morning to be the roughest part.
The peak lines up with your blood alcohol level dropping back to zero. While your body is still processing alcohol, the sedative effects partially mask hangover symptoms. Once the alcohol is fully cleared, you feel the full weight of what it left behind: headache, nausea, fatigue, and that foggy inability to think straight. From that peak, symptoms gradually taper off over the next several hours.
What’s Actually Happening in Your Body
The old explanation blamed acetaldehyde, the toxic byproduct your liver produces when breaking down alcohol. But newer research complicates that story. Blood levels of acetaldehyde measured one, two, and four hours after drinking show no significant correlation with how bad the next day feels. What does correlate is inflammation. Alcohol triggers your immune system to release inflammatory molecules, and the concentration of these molecules in your blood is directly tied to hangover severity.
Think of it less like a poisoning and more like your body mounting an inflammatory response, similar to what happens when you’re fighting off an infection. That’s why hangovers share so many symptoms with being sick: body aches, fatigue, brain fog, and general misery.
Why Some Hangovers Last Longer Than Others
What You Drank
Not all drinks are created equal. Darker spirits like bourbon, brandy, and whiskey contain higher levels of congeners, chemical byproducts of fermentation that your body has to process on top of the alcohol itself. One of the most significant congeners is methanol, which is found in the highest concentrations in red wine and dark spirits, and in the lowest concentrations in beer and vodka. Studies consistently find that bourbon produces worse hangovers than vodka at the same blood alcohol level. If you’re drinking dark liquor, expect a longer recovery window.
Your Age
Hangovers genuinely get worse as you get older, and it’s not just perception. After 65, your body holds less water and carries less lean mass, which means the same amount of alcohol produces a higher blood alcohol concentration. Your metabolism also slows, so alcohol stays in your system longer. But these changes don’t flip on like a switch at a specific birthday. They’re gradual, which is why many people in their 30s and 40s start noticing that recovery takes noticeably longer than it did in college.
Your Genetics
Some people are genetically slower at clearing alcohol’s toxic byproducts. The most well-known variant affects roughly 8% of the world’s population, predominantly people of East Asian descent. This mutation impairs the enzyme responsible for breaking down acetaldehyde, leading to facial flushing, rapid heartbeat, nausea, and headaches even from small amounts of alcohol. If you experience these symptoms, your hangovers are likely more intense and longer-lasting because the toxic intermediary lingers in your bloodstream.
How You Slept
Alcohol wrecks your sleep in a specific, two-phase pattern. In the first half of the night, while your body is still metabolizing alcohol, you fall asleep faster and spend more time in deep sleep. Sounds good, but your body compensates in the second half. As blood alcohol drops, you experience a rebound effect: more time in light, dream-heavy sleep and more frequent awakenings. The result is a night that feels long but leaves you unrested.
Poor sleep doesn’t just make you tired on top of the hangover. Research shows that hangover severity alone accounts for about 11% of the decline in cognitive performance the next day, measured through tasks requiring attention and mental flexibility. Interestingly, total sleep time doesn’t independently explain that cognitive hit. The hangover itself appears to impair your thinking regardless of how many hours you logged.
The 24-Hour Rule
The National Institute on Alcohol Abuse and Alcoholism puts it simply: hangover symptoms can last 24 hours or longer. For most people, anything under 24 hours is a standard hangover running its course. If you’re still feeling significantly unwell after a full day, you’re likely dealing with the tail end of a heavy episode, compounded by dehydration and sleep debt. Rehydrating, eating, and getting genuine rest (not alcohol-disrupted sleep) are the most effective ways to shorten that tail.
There is no proven cure that speeds up the process. Your liver clears alcohol at a fixed rate, and no supplement, greasy breakfast, or “hair of the dog” changes that. What helps is replacing what you’ve lost: water, electrolytes, and calories.
When It’s Not Just a Hangover
A hangover is miserable but not dangerous. Alcohol poisoning is. The key differences are severity and trajectory. A hangover gets worse, peaks, then slowly improves. Alcohol poisoning involves symptoms that are more extreme and don’t follow that arc. Watch for confusion, seizures, vomiting that won’t stop, breathing slower than eight breaths per minute, gaps of more than 10 seconds between breaths, blue or pale skin, low body temperature, or inability to stay conscious. If someone has passed out and cannot be woken up, that’s a medical emergency. Call 911 immediately, even if you’re not certain it qualifies as poisoning.