Most hangovers last up to 24 hours, though some stretch longer depending on how much you drank, what you drank, and your individual biology. Symptoms peak once your body has fully cleared the alcohol from your bloodstream, which is when you typically feel the worst, not while you’re still drinking. From that peak, the clock starts on a recovery period that varies widely from person to person.
The General Timeline
Hangover symptoms begin as your blood alcohol level drops and hit their worst point once it reaches zero. For most people who stopped drinking at the end of a night out, that means symptoms peak somewhere in the morning or early afternoon the next day. The National Institute on Alcohol Abuse and Alcoholism notes that symptoms can last 24 hours or longer from that point.
In practical terms, if you finish your last drink at midnight, you might feel the worst between 8 a.m. and noon, with symptoms gradually fading through the rest of the day. A heavier session pushes the timeline further out. Two-day hangovers are not unusual after particularly heavy drinking, though for a moderate amount, most people feel noticeably better by the following evening.
Why You Still Feel Terrible After the Alcohol Is Gone
Your body breaks down alcohol in two steps. First, it converts alcohol into a toxic byproduct called acetaldehyde. Then a second enzyme converts that into harmless acetate. Acetaldehyde is what causes rapid pulse, sweating, nausea, and flushing. Even after alcohol itself is fully cleared from your blood, the damage acetaldehyde did to proteins and cells lingers, which is why you feel bad well after you’ve technically “sobered up.”
Alcohol also suppresses your body’s ability to produce glucose, the primary fuel source for your brain. That dip in blood sugar contributes to the fatigue, weakness, and mood disturbances that make hangovers feel like more than just a headache. Your body needs time to restore normal glucose production, and that process doesn’t happen instantly once the alcohol is gone.
Certain drinks contain trace amounts of methanol, a different type of alcohol your body processes using the same enzymes. The problem is that methanol’s byproducts (formaldehyde and formic acid) are far more toxic. Research has shown that blood methanol levels can stay elevated for several hours after the main alcohol is metabolized, which lines up neatly with the extended timeline of hangover symptoms.
What You Drink Matters
Darker alcoholic drinks like bourbon, red wine, and brandy contain higher levels of congeners, chemical compounds produced during fermentation that contribute to flavor and color. Studies comparing bourbon (high congeners) to vodka (essentially no congeners) found that bourbon produced more severe hangover ratings. That said, the amount of alcohol consumed had a considerably stronger effect on hangover severity than the type of drink. Choosing a “cleaner” spirit may help at the margins, but it won’t save you from drinking too much.
Sleep Disruption Extends Recovery
Alcohol initially makes you fall asleep faster, but it wrecks the second half of your night. Research shows that after drinking, people wake up significantly more often during the later sleep cycles and spend less time in the deep, restorative stage of sleep. This disruption is concentrated in the second half of the night, meaning you may sleep for a normal number of hours but wake up feeling unrested. That poor-quality sleep compounds the fatigue and brain fog of the hangover itself, and it’s one of the main reasons a hangover can drag well into the next day even when other symptoms have faded.
Anxiety and Mood Symptoms
The irritability, low mood, and anxiety that often accompany a hangover have earned the informal name “hangxiety.” These psychological symptoms follow the same general timeline as physical ones: they tend to be most severe the day after drinking and can persist for 24 hours or sometimes longer. Alcohol temporarily alters brain chemistry, boosting calming signals while you’re drinking and then leaving a deficit as your brain recalibrates. If you already deal with anxiety, this rebound effect can feel especially intense.
Why Hangovers Get Worse With Age
If your hangovers seem to hit harder and last longer than they used to, you’re not imagining it. The enzymes your liver uses to break down alcohol become less active as you age. At the same time, your body’s total water content decreases with age, which means the same amount of alcohol produces a higher concentration in your blood. Both changes mean your body takes longer to process the same number of drinks, and the toxic byproducts stick around longer.
Genetics Play a Role
Some people are genetically predisposed to worse hangovers. Variations in the genes that control alcohol-processing enzymes are especially common among people of East Asian ancestry and lead to a buildup of acetaldehyde that the body can’t clear efficiently. The most visible sign is facial flushing after even small amounts of alcohol, but nausea, low blood pressure, and headaches often come with it. If you experience the flush reaction, your hangovers are likely more intense and longer-lasting because your body is slower to neutralize the most toxic stage of alcohol breakdown.
What Hydration Can and Can’t Do
Drinking water or electrolyte beverages helps with one specific piece of the hangover: dehydration. Alcohol is a diuretic, meaning it signals your kidneys to release more fluid than usual. That fluid loss contributes to headache, dizziness, and fatigue, and replacing those fluids genuinely helps those particular symptoms. But many hangover symptoms, including nausea, irritability, and sensitivity to light, are driven by inflammation, toxic byproducts, and temporary changes in brain chemistry. Those symptoms take roughly 24 hours to resolve as your body finishes processing and clearing everything. Hydration is helpful, but it’s not a cure.
Hangover vs. Alcohol Withdrawal
A hangover and alcohol withdrawal can look similar on the surface, but they’re very different situations. A hangover follows a single episode of heavy drinking and resolves within a day or so. Alcohol withdrawal happens to people whose bodies have become physically dependent on regular drinking. Withdrawal symptoms can begin within 8 hours of the last drink, peak at 24 to 72 hours, and in some cases continue for weeks. If you experience tremors, hallucinations, or symptoms that intensify rather than improve after 48 hours, that’s a different medical situation from a standard hangover.