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What Causes a Hangover Headache?

A hangover headache is a throbbing, pounding misery. As you already know, hangovers are caused by drinking too much alcohol. A single alcoholic drink is enough to trigger a hangover for some people, while others may drink heavily and escape a hangover entirely.

A hangover is characterized by symptoms such as headache, nausea, fatigue, poor concentration, mood disturbance, and increased sensitivity to light and noise. But headache itself is among the most common of hangover symptoms and can render even the strongest among us, useless. But, what actually happens in the body, to trigger the pain?

Various factors may contribute to what causes a hangover headache:

  • Alcohol triggers an inflammatory response from your immune system. Your immune system may trigger certain agents that commonly produce physical symptoms, such as headache, an inability to concentrate, memory problems, decreased appetite and loss of interest in usual activities.

  • Alcohol causes your blood vessels to expand, which can lead to pounding headaches.

  • Alcohol causes your body to produce more urine. In turn, urinating more than usual can lead to dehydration — often indicated by thirst, dizziness and lightheadedness.

  • Alcohol can make you sleepy, but it prevents deeper stages of sleep and often causes an awakening in the middle of the night. This may leave you groggy and tired, leading to headaches.


Alcohol is a drug. This means that, when you ingest it, it alters the chemical balances within your body to create a physiological effect - you get intoxicated. Once alcohol enters the bloodstream it begins to change certain processes. More specifically, it suppresses your body's antidiuretic hormone (“vasopressin”) that sends fluid back into your body while simultaneously acting as a diuretic, causing water to be flushed out of your system much more rapidly than normal. This explains the constant trips to the restroom during imbibing.

According to studies, drinking about 250ml of an alcoholic beverage causes the body to expel 800ml of water; that's almost four times as much liquid lost as gained. This diuretic effect decreases as the alcohol in the bloodstream decreases, but the after effects result in a hangover.1

The morning after excessive drinking, the body sends a desperate message to replenish its water supply -- usually manifested in the form of an extremely dry mouth. Headaches result from dehydration because the body's organs try to make up for their own water loss by stealing water from the brain, causing the brain to decrease in size and pull on the membranes that connect the brain to the skull, resulting in pain. Remember, our brain is around 70 percent water, and dehydration leads to brain shrinkage, which is one of the causes of the hangover headache.


The frequent urination also expels salts and potassium that are necessary for proper nerve and muscle function; when sodium and potassium levels get too low, headaches, fatigue, and nausea can result.


People who drink heavily often use other drugs and many of them smoke cigarettes. The combined effect of nicotine and alcohol causes a major spike of dopamine, the chemical that’s responsible for the warm-and-fuzzy feeling we get after a couple of drinks. But these substances can cause their own set of hangover type symptoms.

Recent research has confirmed that your hangover headache will be worse if you smoke when you drink. A study found that people who dragged on a cigarette or two while drinking alcohol were twice as likely to experience painful hangover headaches than those who boozed without smoking.2


While the general rule of thumb is, the more you drink the worse you'll feel the next day, there is no magic formula to reveal how much you can imbibe and escape the hangover headache. We've all been there, and many people will have their own tricks to help take to edge off the pain, but the ones we present here are the ones recommended by the medical community.

  • Rehydration - is the key to avoiding a hangover headache. Drink plenty of water - at least a pint of seltzer water, broth or a sports drink before going to bed.

  • Congeners - chemical substances in alcohol drinks that darken the color, have been implicated in hangover headaches. The darker the color of the drink, the more likely it is to cause a hangover - so avoid dark liquor as much as possible.4,5

  • Eat - Eating food while drinking helps to reduce the negative effects of alcohol consumption. High-fat foods are particularly good in absorbing alcohol, which spreads the release of the alcohol into the bloodstream over a longer period of time.

  • Vitamin B - Vitamin depletion can be part of the reason we get a hangover and vitamin B levels tend to get tapped out when we drink alcohol. A supplement that includes vitamin B could be beneficial as a mitigating agent before or after going out drinking to avoid a hangover headache.

  • Willow bark - Rich in salicylates, white willow bark is both anti-inflammatory and analgesic (pain reducing) making it a great remedy for hangovers. It is the original aspirin after all. Some believe that this makes it gentler on your stomach than lab-created aspirin.


  1. The effect of alcohol on the renal excretion of water and electrolyte.

  2. Role of Tobacco Smoking in Hangover Symptoms Among University Students

  3. The Alcohol Hangover

  4. The role of beverage congeners in hangover and other residual effects of alcohol intoxication: a review

  5. Concentration changes of methanol in blood samples during an experimentally induced alcohol hangover state

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