A typical hangover lasts about 12 hours from the time you wake up, or roughly 18 to 19 hours from your last drink. For most people, symptoms fall within a 14- to 23-hour window and resolve on their own without medical treatment. How much you drank, what you drank, and how well you slept all influence whether you’re closer to the short or long end of that range.
The General Timeline
Hangover symptoms don’t start while you’re still drunk. They begin as your blood alcohol level drops back toward zero, which is why you often feel fine going to bed but wake up miserable. In one study, the hangover state was defined as beginning about 13 hours after drinking, the point at which blood alcohol had fully cleared.
From there, symptoms tend to peak in the morning and early afternoon. Starting around 16 hours after your last drink, severity drops off noticeably. By 21 hours after drinking, most people’s symptom scores return close to zero. So if you stopped drinking at midnight, expect the worst between roughly 8 a.m. and noon, with significant improvement by early evening. Some hangovers, particularly after heavy or prolonged drinking, can stretch past 24 hours.
Why You Feel So Bad
A hangover isn’t just dehydration, though that’s part of it. Your body treats alcohol as a mild toxin and breaks it down in two steps. First, your liver converts alcohol into a compound called acetaldehyde, which is significantly more toxic than alcohol itself. Then a second enzyme converts acetaldehyde into something harmless. The lag between those two steps is responsible for many of the classic symptoms: headache, nausea, and general misery.
Your immune system also plays a role. During a hangover, your body produces elevated levels of certain immune signaling molecules, the same ones involved in inflammation and infection. This immune disruption helps explain why a hangover can feel oddly similar to coming down with something: fatigue, body aches, nausea, and brain fog that seem out of proportion to “just drinking too much.”
What Makes a Hangover Last Longer
Several factors push your hangover toward the longer end of that 14- to 23-hour window.
- Amount consumed: More alcohol means more acetaldehyde for your liver to process, which extends the timeline.
- Dark liquors: Bourbon, whiskey, red wine, and other darker drinks contain higher levels of congeners, byproducts of fermentation that can worsen symptoms. Clear spirits like vodka and gin have fewer congeners and tend to produce milder hangovers at the same alcohol volume.
- Poor sleep: Alcohol fragments your sleep even if you don’t remember waking up. You spend less time in the deep, restorative stages of sleep, and you’re more prone to waking during the night. The resulting sleep deprivation stacks on top of the hangover itself, making fatigue, poor concentration, and brain fog last well into the next day.
- Age: Your liver becomes less efficient at processing alcohol as you get older. Specifically, it may produce less of the enzyme that clears acetaldehyde, allowing that toxic intermediate to linger longer. This is a major reason hangovers feel worse and last longer in your 30s and 40s compared to your 20s.
- Empty stomach: Drinking without food speeds alcohol absorption, leading to a higher peak blood alcohol level and a rougher morning.
What Actually Helps Recovery
No pill or remedy has been proven to cure a hangover. The process is fundamentally about waiting for your liver to finish clearing toxic byproducts and for your immune system to settle back down. But you can make the wait less painful.
Water and electrolytes address the dehydration component. Alcohol is a diuretic, so you lose more fluid than you take in while drinking. Rehydrating won’t eliminate the hangover, but it helps with headache and dry mouth. Eating bland, easy-to-digest food gives your body fuel and can settle nausea. A standard over-the-counter pain reliever can take the edge off a headache, though avoid anything that’s hard on the stomach if you’re already feeling nauseous.
Sleep is probably the single most effective recovery tool. Since alcohol disrupted your sleep quality the night before, getting additional rest the next day lets your brain catch up on the restorative sleep it missed. Many people find that even a short nap dramatically improves how they feel.
When a Hangover Feels Too Long
If your symptoms last well beyond 24 hours, something else may be going on. Severe dehydration, alcohol withdrawal (which can occur in regular heavy drinkers), and alcohol-related gastritis can all mimic or extend hangover symptoms. Vomiting that continues past the first several hours, confusion, or a fever are not typical hangover features and warrant medical attention. For the vast majority of people, though, even a rough hangover will resolve within a single day.