A typical hangover lasts about 18 hours from your last drink, or roughly 12 hours from when you wake up the next morning. Most people’s symptoms fall within a 14- to 23-hour window, meaning a hangover that starts after a Saturday night out usually clears by Sunday evening. Several factors can push that timeline shorter or longer.
When Symptoms Start and Peak
Hangover symptoms don’t hit while you’re still drinking. They begin about six to eight hours after you stop, which is when your blood alcohol level drops significantly. If you finish your last drink at midnight, expect symptoms to arrive between 6 and 8 a.m. They tend to peak in the morning hours and gradually taper through the afternoon and evening.
This timing explains why hangovers feel worst right when you wake up. Your body has been processing alcohol all night, and the toxic byproducts of that process are at their highest concentration just as you’re dragging yourself out of bed.
What’s Happening in Your Body
Your liver breaks alcohol down into a compound called acetaldehyde before converting it into harmless acetic acid. Acetaldehyde is significantly more toxic than alcohol itself, and while it’s circulating in your bloodstream, it drives many of the classic hangover symptoms: nausea, headache, flushing, and a racing heart. How quickly your body clears acetaldehyde depends largely on your genetics. People with a slower version of the enzyme responsible for breaking it down (common in people of East Asian descent) tend to experience more intense and longer-lasting symptoms.
Alcohol also triggers an inflammatory response throughout your body. Pro-inflammatory signaling molecules spike during and immediately after drinking, and some of these remain elevated for 24 to 96 hours after your last drink. This lingering inflammation contributes to the brain fog, fatigue, and general malaise that can persist even after the headache and nausea have faded.
Why Your Sleep Makes It Worse
Alcohol sedates you into sleep faster than usual and initially pushes you into deep sleep while suppressing the lighter, dream-heavy stages your brain needs for restoration. The problem comes in the second half of the night. As your blood alcohol drops, your sleep becomes fragmented. You wake up more often, spend more time in light sleep, and lose the restorative cycles your brain was counting on.
Research tracking people’s sleep on hangover nights found that the number and duration of nighttime awakenings correlated directly with how severe six different hangover symptoms were the next day, including overall severity. Poor sleep doesn’t just make you tired on top of being hungover. It appears to intensify the hangover itself, making symptoms feel heavier and cognitive recovery slower. People performing mental tasks while hungover showed measurably worse performance, with hangover severity accounting for about 11% of the decline in complex thinking speed.
What Makes a Hangover Last Longer
How Much You Drank
This is the biggest factor. More alcohol means more acetaldehyde to clear, more inflammation, and more dehydration. There’s no trick that changes this math. A night of heavy drinking simply gives your body more work to do.
What You Drank
Dark liquors like bourbon, brandy, cognac, red wine, and dark whiskey contain higher levels of chemical byproducts called congeners, which form during fermentation and aging. These compounds add flavor and color but also add to the toxic load your body has to process. Clear drinks like vodka, gin, white wine, light rum, and light beer have fewer congeners and tend to produce milder aftereffects. Mixing dark spirits with sugary mixers can make things worse.
Your Age
Hangovers genuinely get harder as you get older, and it’s not just perception. Several changes stack against you over time. Your liver enzymes shift, slowing your ability to break down alcohol. Circulation decreases with age, meaning less blood flows through your liver and toxic metabolites build up faster. You also lose about 3% to 8% of your lean muscle mass per decade after age 30, and since muscle tissue holds water, less of it means alcohol concentrates more in your bloodstream. On top of all that, medications you take for age-related health issues compete for the same liver enzymes that process alcohol, further slowing everything down.
The net result: the same number of drinks that gave you a mild headache at 25 can knock you out for an entire day at 45.
Hydration and Food
Drinking on an empty stomach speeds alcohol absorption, which means a faster spike in blood alcohol and a sharper crash afterward. Dehydration compounds the headache and fatigue. Neither eating nor drinking water will prevent a hangover entirely, but both can blunt the severity and shorten recovery time.
The 24-Hour and Two-Day Hangover
Most hangovers resolve within a day. But some people report feeling “off” for 48 hours or more after a particularly heavy night. This isn’t unusual. The inflammatory molecules your body releases in response to alcohol can stay elevated for two to four days after you stop drinking. While the acute symptoms (nausea, pounding headache, sensitivity to light) typically fade within 18 to 23 hours, subtler effects like fatigue, irritability, difficulty concentrating, and low mood can linger into the second day.
If you’re still feeling significant nausea, vomiting, or confusion well past the 24-hour mark, that may point to something beyond a standard hangover, such as alcohol poisoning or withdrawal, especially if heavy drinking is frequent.
Can You Speed Up Recovery
No supplement, “hangover cure,” or IV drip has been proven to meaningfully shorten how long a hangover lasts. Your liver processes alcohol at a fixed rate (roughly one standard drink per hour), and no pill changes that. What does help is managing symptoms while your body finishes the job: staying hydrated, eating bland foods when you can tolerate them, and sleeping. Rest is particularly important because alcohol already robbed you of quality sleep the night before, and your brain needs that recovery time.
Time is the only reliable cure. For most people, that means somewhere between 14 and 23 hours of discomfort before things return to normal.