A typical hangover lasts about 24 hours, starting once your body finishes processing alcohol and your blood alcohol level drops back to zero. Most people feel their worst in the morning after a night of drinking, with symptoms gradually fading through the day. How long yours actually lasts depends on how much you drank, what you drank, your genetics, and a few other factors that can push recovery well past that 24-hour mark.
When Symptoms Peak and When They Fade
Hangover symptoms hit their worst point right around the time your blood alcohol concentration returns to zero. Your liver processes roughly one standard drink per hour, so if you had six drinks and stopped at midnight, your body may not clear the alcohol until early morning. That’s when the headache, nausea, and fatigue set in at full force.
For most people, the arc looks like this: you wake up feeling terrible, symptoms hold steady through mid-morning, and then gradually improve over the next several hours. By the following evening, roughly 24 hours after symptoms began, most people feel close to normal. But heavier drinking sessions can extend that timeline, and some people report feeling off for 48 to 72 hours after a particularly heavy night.
What’s Actually Happening in Your Body
The misery of a hangover comes from several overlapping problems, which is part of why it takes so long to resolve. Your liver breaks down alcohol (ethanol) into a toxic byproduct called acetaldehyde before eventually converting it into harmless acetic acid. That middle step is the problem. Acetaldehyde is irritating to your tissues and contributes directly to nausea, headache, and that general feeling of being unwell.
But ethanol isn’t the only thing your liver has to deal with. Alcoholic drinks also contain small amounts of methanol, another type of alcohol produced during fermentation. Your liver prioritizes clearing ethanol first. Only after the ethanol is gone does it turn to methanol, breaking it down into formaldehyde, another toxic compound. This delayed processing of methanol is a key reason why you often feel fine while still drinking but miserable the next morning. Your body is essentially dealing with a second wave of toxins hours after you stopped.
Dehydration compounds everything. Alcohol suppresses the hormone that tells your kidneys to retain water, so you lose more fluid than you take in. It also causes your body to excrete sugar through urine, leading to low blood sugar. The combination of dehydration, low blood sugar, and lingering toxic byproducts is what makes a hangover feel like a full-body event rather than just a headache.
Why Dark Liquors Make It Worse
Not all drinks produce equal hangovers. Dark-colored spirits like bourbon, whiskey, and red wine contain higher levels of compounds called congeners, which are chemical byproducts of fermentation that give these drinks their color and flavor. Research comparing bourbon drinkers to vodka drinkers found that bourbon, a high-congener liquor, produced noticeably more severe hangovers than vodka, which contains very few congeners.
This doesn’t mean clear spirits give you a free pass, but if you’ve noticed that whiskey leaves you feeling worse than gin or vodka the next day, the congener content is a likely explanation. More congeners means more toxic byproducts for your liver to process, which can both intensify symptoms and stretch out recovery time.
Genetics Play a Bigger Role Than You Think
Some people genuinely recover from hangovers faster than others, and much of that comes down to genetics. The enzyme responsible for converting acetaldehyde into harmless acetic acid varies in activity from person to person. In some people, particularly those of East Asian descent, a genetic variant makes this enzyme less active or completely inactive. When that happens, acetaldehyde builds up in the blood and tissues instead of being cleared efficiently.
People with this variant often experience flushing, rapid heartbeat, nausea, and intense hangover-like symptoms even from small amounts of alcohol. If you’ve always seemed to get worse hangovers than your friends despite drinking similar amounts, a less efficient version of this enzyme could be the reason. Your body simply takes longer to neutralize the toxic byproducts.
What Actually Helps (and What Doesn’t)
The hard truth is that time is the only thing that fully resolves a hangover. Your liver works at a fixed rate of about one drink per hour, and no supplement, greasy breakfast, or “hair of the dog” speeds that up. Drinking more alcohol the next morning may temporarily mask symptoms by delaying the processing of methanol, but it just postpones the inevitable and adds more toxins to the queue.
That said, you can make the 24 hours more bearable. Drinking water between alcoholic drinks and before bed helps offset dehydration, which is responsible for a significant chunk of the headache and fatigue. Eating before and during drinking slows alcohol absorption, which means your liver doesn’t get overwhelmed as quickly. Anti-inflammatory pain relievers can help with headache, though you’ll want to avoid anything that’s hard on the liver while it’s already working overtime.
If your hangovers routinely last more than a day or seem disproportionate to what you drank, that’s worth paying attention to. It could point to a less efficient enzyme system, sensitivity to congeners, or simply drinking more than your body can comfortably process in one session. The most reliable way to shorten a hangover is to reduce how much your liver has to deal with in the first place: fewer drinks, spaced further apart, with water and food alongside them.