How Long Does a Hangover Last?
Quick Answer
12–24 hours for most people. Symptoms typically peak 12–14 hours after blood alcohol concentration returns to zero and resolve within a day. Severe hangovers can linger up to 72 hours.
Typical Duration
Quick Answer
A hangover typically lasts 12–24 hours. Symptoms begin as blood alcohol concentration (BAC) drops toward zero, peak around 12–14 hours after BAC hits zero, and resolve within 24 hours for most people. Heavy drinking episodes can produce hangovers lasting up to 72 hours.
Hangover Symptom Timeline
| Time After Last Drink | What Happens |
|---|---|
| 0–6 hours | Still intoxicated; BAC falling, sleep disrupted |
| 6–8 hours | BAC approaches zero; early symptoms begin (headache, nausea) |
| 8–14 hours | Symptoms peak — worst headache, nausea, fatigue, dehydration |
| 14–20 hours | Gradual improvement, lingering fatigue and brain fog |
| 20–24 hours | Most symptoms resolve for moderate drinkers |
| 24–72 hours | Residual fatigue, anxiety ("hangxiety") in heavy episodes |
What Causes a Hangover?
Hangovers are driven by several biological mechanisms:
- Dehydration: Alcohol is a diuretic — it suppresses vasopressin (ADH), causing increased urination and fluid loss
- Acetaldehyde toxicity: The liver converts alcohol to acetaldehyde, a toxic compound 10–30x more toxic than alcohol itself
- Inflammation: Alcohol triggers cytokine release, causing headache, nausea, and fatigue
- Stomach irritation: Alcohol increases stomach acid and delays gastric emptying
- Blood sugar drops: Alcohol impairs gluconeogenesis, leading to low blood sugar
- Sleep disruption: Alcohol suppresses REM sleep, reducing sleep quality even if you sleep a full 8 hours
Factors That Affect Duration
| Factor | Shorter Hangover | Longer Hangover |
|---|---|---|
| Amount consumed | 3–4 drinks | 8+ drinks |
| Body weight | Higher body mass | Lower body mass |
| Age | Under 30 | Over 40 |
| Hydration | Drank water between drinks | No water |
| Food | Ate before/during drinking | Drank on empty stomach |
| Drink type | Clear spirits (vodka, gin) | Dark spirits (bourbon, red wine) |
| Genetics | Fast acetaldehyde metabolism | Slow metabolism (common in East Asian populations) |
| Sleep | 7+ hours post-drinking | Under 5 hours |
Congeners and Drink Type
Congeners are byproducts of fermentation that contribute to hangover severity. Darker drinks contain more congeners:
- High congeners (worse hangovers): Bourbon, brandy, red wine, dark rum, whiskey
- Low congeners (milder hangovers): Vodka, gin, white wine, light beer, white rum
A study in Alcoholism: Clinical and Experimental Research found that bourbon caused significantly worse hangovers than vodka at equivalent alcohol doses.
What Actually Helps
- Hydrate aggressively: Water, coconut water, or electrolyte drinks (Pedialyte, sports drinks)
- Eat bland carbohydrates: Toast, crackers, bananas — helps stabilize blood sugar
- Take ibuprofen or aspirin: For headache (avoid acetaminophen/Tylenol — it stresses the liver alongside alcohol)
- Sleep more: Rest is the single most effective remedy
- Drink broth or soup: Replaces sodium and fluids
- Coffee (small amount): Can help headache via vasoconstriction, but can worsen dehydration
What Doesn't Help (Myths)
- "Hair of the dog" (more alcohol): Delays the hangover, doesn't cure it, and risks dependence
- Greasy food the morning after: Doesn't absorb alcohol (it's already metabolized); eating before drinking helps
- Activated charcoal: Doesn't bind alcohol effectively; no evidence it helps
- IV drip bars: Expensive hydration — drinking water is equally effective for typical hangovers
- "Hangover pills" and supplements: Most lack clinical evidence; some B-vitamin and zinc studies show modest benefit
When to Seek Medical Attention
- Vomiting blood or dark/coffee-ground material
- Confusion, seizures, or loss of consciousness
- Severe chest pain or irregular heartbeat
- Inability to keep any fluids down for 12+ hours
- Symptoms lasting beyond 72 hours (may indicate alcohol withdrawal, not a hangover)