You had a fun night out with friends, indulging in a few drinks to unwind and enjoy yourself. But as you wake up the next day, you quickly realize you’re paying extra, beyond the bar tab.

A throbbing headache, fatigue, nausea, and a general feeling of misery that makes you swear off drinking forever. Sounds familiar? Welcome to the world of hangovers.

Science knows surprisingly little about what causes hangovers or how we can tackle them. While there are thousands of studies dealing with alcohol one way or the other, there are only a handful of published scientific papers that explore what causes hangovers and whether or not there’s a cure. That’s quite disappointing, considering hangovers are the bane of every weekend warrior all over the world.

What physiological changes or biological interactions with alcohol could be responsible for the diabolical melange of headache, nausea, poor appetite or diarrhea, to name a few? According to the Alcohol Hangover Research Group (AHRG), “an international expert group” which aims to “elucidate the pathology, treatment, and prevention of the alcohol hangover,” most of what we know about the morning-after effects of heavy drinking is wrong.

What causes hangovers?

According to the AHRG, “alcohol hangover develops when blood alcohol concentration (BAC) returns to zero, and is characterized by a feeling of general misery that may last more than 24 h.” 

In a 2008 article published in the journal Alcohol & Alcoholism, Dutch researcher Joris Verster dispels a number of popular beliefs surrounding the triggers for alcohol hangover symptoms.

One of the most widely cited reasons why people feel wretched following heavy drinking is dehydration. Alcohol is known to suppress a hormone called vasopressin, which typically keeps you from feeling the need to urinate. Because you urinate more often, the body also loses more water. What’s more, if you’re drinking whiskey or other spirits, water is likely not on the menu for the rest of the evening, which worsens dehydration. Why is it then that even if you neck copious amounts of water before you go to bed or while drinking alcohol, there will still be a dreadful hangover the next morning? That’s because dehydration doesn’t have much to do with it, says Verster.

Research suggests that levels of electrolytes — naturally occurring elements and compounds in the body that conduct electricity when dissolved in water — are more or less the same in both controls and people with hangovers. Even in those cases where there were some differences in electrolyte levels, these didn’t correlate with the severity of hangover symptoms. What’s more, studies haven’t been able to link hormones associated with dehydration and hangover severity.

According to Verster “alcohol hangover and dehydration are two independent yet co-occurring processes that have different underlying mechanisms.” In other words, drinking alcohol will dehydrate causing symptoms such as dry mouth and thirst. Drinking alcohol will lead to a hangover but not because you’re dehydrated. 

Why you get headaches after drinking

To be fair, there’s one major hangover symptom that can be attributed, or at least largely so, to dehydration: the annoying monster headache. Blood vessels narrow because of dehydration, restricting the flow of blood and oxygen to the brain in the process. In an attempt to restore fluid levels, blood vessels begin to dilate causing swelling around the brain.

The nausea we feel the morning after can be explained by alcohol’s effects on the stomach and intestines, which become irritated, causing inflammation. Alcohol also triggers the production of extra gastric acid along with more pancreatic and intestinal secretion.

Acetaldehyde, a byproduct that builds up in response to alcohol processing in the body, is thought to be 30 times more toxic than alcohol itself. Studies have shown that it produces hangover symptoms and the substance may partly explain the origin of hangovers.

Another intriguing hypothesis that might explain the origin of hangovers suggests that alcohol affects the immune system. Previously, researchers found a strong correlation between high levels of cytokines, which are the immune system signaling molecules, and hangover symptoms. When the body gets infected, cytokines trigger fever or inflammation, but it seems that excessively drinking alcohol can trigger a similar response, causing symptoms like muscle aches or headaches, but also cognitive effects like memory loss and irritation.

Do hangovers get worse as you age?

Some people seem more prone to hangovers. One study found that age may play a big part in hangovers, with adolescent drinkers reporting the symptoms of alcohol withdrawal less frequently than older adults. Another study found adolescent rats are less sensitive to the effects a hangover has on anxiety and sociability. 

As we age, our body’s ability to process alcohol decreases, meaning it takes longer for your liver to break down the alcohol in your system. This explains why older people are at a higher risk of damaging their liver due to drinking. Additionally, as you get older, your body has less water content, which can make you more susceptible to dehydration and its associated symptoms, such as headaches and fatigue.

Another factor that may contribute to age-related hangovers is the quality of your sleep. As you age, your sleep patterns change, and you may find it harder to get a good night’s rest. Alcohol can disrupt your sleep even further, leading to less restful and restorative sleep that can exacerbate hangover symptoms.

The jury isn’t out yet though as a recent Danish study examined younger and older adult drinkers and found that the tendency to experience hangovers after binge drinking actually decreased with age.

Women seem to report the worst hangover effects, but that may be due to lower body weight than men rather than some intrinsic female biology. A total of 12.6 percent of women surveyed in a 2012 study say they ‘almost always’ or ‘always’ have a hangover after having more than five drinks at a party. The figure for men is 6.1 percent.

Are some types of alcohol more likely to give you a hangover?

But it’s not just alcohol that can cause headaches during a night of drinking. The type of alcohol you consume, as well as the amount and timing, can also play a role. Alcoholic drinks with congeners — substances produced during the alcohol fermentation process or added later in the production — may enhance the toxicity effect of alcohol and, hence, increase the likelihood of a hangover.

For example, drinks that are high in congeners such as red wine, whiskey, and tequila, are more likely to cause headaches than drinks that are low in congeners, such as vodka and gin. Studies from the 1980s suggest that patients develop more headaches from red wine than from white wine. Similarly, vodka is ‘safer’ than bourbon. Drinking on an empty stomach or staying up late can also increase your risk of developing a headache.

Does Drinking More Help With Hangovers?

It’s a common misconception that drinking more alcohol can help alleviate hangover symptoms. After all, if alcohol is the cause of your hangover, wouldn’t drinking more of it help counteract those effects?

Unfortunately, this is not the case. While drinking more alcohol may temporarily alleviate some symptoms, such as headache and nausea, it can ultimately make your hangover worse. Drinking more alcohol can dehydrate you further, exacerbate inflammatory responses, and make it harder for your liver to process the alcohol in your system, leading to more severe and longer-lasting hangovers.

So what can you do to cure a hangover?

There are a couple of things you can do to make things easier for you the next morning.

• Don’t drink too much alcohol in the first place… but if that’s not an option,
• At least don’t drink quickly or on an empty stomach.
• Food doesn’t absorb the alcohol but a full digestive tract will slow down alcohol’s absorption into the bloodstream. Eating also replenishes electrolytes.
• As we’ve learned, dehydration doesn’t really cause a hangover but it is partly responsible for some symptoms. Drinking a glass of water for every alcoholic beverage could prevent a very serious headache.

You’ll find many urban legends and anecdotal cures for hangovers — from coffee, eggs Benedict, tripe soup, and all the way to shrimp — but there’s no study that suggests any of these works. What you can do, however, is alleviate some of the symptoms. Aspirin or ibuprofen (Advil) can treat headaches and muscle pain while drugs like Tums or Pepto-Bismol can reduce nausea.

And if all else fails, remember that time is the ultimate hangover cure – so sit back, relax, and wait for your body to do its thing.