How To Recover From A 2-Day Hangover


This post is long. If you don’t read it, here’s a summary:

  • Supplement vitamin B1 (thiamine) when you drink. Thiamine is depleted by alcohol and is responsible for alcohol-induced brain damage that chronic alcoholics sometimes experience (Wernicke-Korsakoff Encephalopathy).
  • Curiously, some people experience a cognitive boost while hungover. This is probably a genetic effect mixed with glutamate rebound (read more).
  • Binge drinking is much, much harder on your brain than drinking smaller amounts more frequently. For example, 7 drinks in a single night are clearly harmful but 1 drink per day for 7 days may be beneficial.
  • Alcohol-induced brain damage doesn’t occur when you’re drunk. It occurs when you’re in the withdrawal state. Alcohol depresses CNS function; your brain “pushes back” by upregulating excitatory signaling. When the alcohol is gone your brain has overcorrected, potentially leading to glutamate excitotoxitiy.
  • If you think you drink too much, I recommend counting your drinks and keeping a log. Tracking things seems to be motivating, as evidenced by products like the FitBit.
  • Eggs the morning after a bender may be beneficial, because eggs are choline-rich brain food.
  • If you’re experiencing 2-day hangovers it’s a sign to cut back on drinking. For immediately relief, see the steps below.

I feel bad for people who don’t drink. When they wake up in the morning, that’s as good as they’re going to feel all day.

-Frank Sinatra

Hangovers are an inevitable consequence of alcohol use (and misuse).

If you know what it means to be truly hungover, you’ve also made empty promises to never drink again. Hangover amnesia is swearing off alcohol on Monday and drinking per usual on Wednesday. And it’s a familiar phenomenon.

Hangovers are easy on the young. Aging seems to diminish our ability bounce back from hangovers. In college, I remember being hangover-free until my junior year. Now I experience 2-day hangovers that give me gray hairs and make me seriously re-evaluate my priorities.

There are a handful of theories about the cause of hangovers. Unexpectedly, the science of hangovers is not as well understood as you might imagine. Apparently, Newton could invent (or discover?) calculus by armchair philosophizing but centuries later we can’t figure out why a bender makes you hate yourself the next day.

Caption: Hemingway’s commitment to ethanol intoxication was unparalleled.

I don’t stop drinking until I hate myself.

-Hemingway (allegedly)

The main theories about the cause of hangovers can be distilled (no pun intended) down to:

  • accumulation of acetaldehyde (a metabolite of alcohol)
  • low blood sugar (hypoglycemia) and impaired use of sugar (glucose is needed to make energy or ATP)
  • inflammation (cytokines, prostaglandins)
  • impurities (congeners in alcohol which can be metabolized to toxins like formaldehyde)
  • dehydration
  • metabolic acidosis (the fluid around cells becomes too acidic)

Armchair theories are interesting. But they’re hardly helpful when you have a pounding headache and the mere thought of tequila makes you feel deeply unwell.

In this post, I’ll be imparting some actionable steps you can take to avoid hangovers altogether and bounce back more quickly when they strike.

I Don’t Care About Science, I Just Want Hangover Relief

Fair enough. Here’s the take-home message in under 100 words.

  • Drink vodka next time. It’s a cleaner alcohol that contains fewer congeners. Congeners are impurities that worsen hangover. Bourbon is the worst offender.
  • Get extra sleep. Your sleep quality after a night on the town is impaired. Glutamatergic rebound may make you feel alert after six hours of sleep, but alcohol impairs sleep quality.
  • Rehydrate. Pick up an electrolyte-rich beverage like gatorade. Rehydrate until you don’t feel thirsty. Then drink another bottle.
  • Eat. The last time I was on a bender, I felt too nauseous to eat in the morning. The key is to eat something neutral like white bread.
  • Be aware of gender differences. The female sex is more vulnerable to hangovers.
  • Avoid polysubstance use (or abuse). We’ve all done it, but co-ingesting psychoactive drugs with alcohol will exacerbate hangovers.
  • Supplement vitamin B1. Whenever an alcoholic comes into the emergency room, the first thing the doctors do is administer vitamin B1. Alcohol depletes vitamin B1, sometimes so severely that it results in brain damage (Wernicke-Korsakoff encephalopathy).
  • Supplement magnesium. Magnesium protects your brain from excitotoxicity. During a hangover, your brain is hyper-excitable and magnesium can help by blocking those NMDA-type glutamate receptors.

Defining A Hangover

Socrates would like to say that you should probably define a term before discussing it at length.

You’d surprised how many academic papers attempt to come up with a rigorous definition of a hangover and fail to reach a consensus.

I’ll skirt the controversy and provide the following pedestrian definition:

Distress that appears several hours after alcohol intoxication.

That was easy. Researchers also seem to agree on these (fairly obvious) facts:

  • Hangovers are connected to alcohol intoxication and also to heavy episodic drinking in young adults (Delk and Meilman, 1996; Mallett et al., 2006; Jackson, 2008).
  • They’re the most common adverse effects of alcohol consumption (Slutske et al., 2003; Wright, 1997).
  • Hangovers are a burden on society. Think of the economic costs linked to work and academic absenteeism (Foster and Vaughan, 2005; McFarlin and Fals-Stewart, 2002; Ragland et al., 2002). Hangovers aren’t well understood, although several authors have focused their attention on the question.

Originally, researchers attributed hangovers to either alcohol itself, alcohol metabolites, alcohol withdrawal or alcohol drinks congener effects (Swift and Davidson, 1998; Wiese et al., 2000).

What are “congener effects”? They’re “…minor compounds other than ethanol that occur naturally in alcohol beverages as a result of distilling and fermenting processes” So not ethanol itself, but natural impurities.

Several factors affect hangover severity:

  • genetic predisposition to alcoholism – If you’re vulnerable to alcoholism, you’ll tend to experience worse hangovers (Earleywine, 1993a,b; Span and Earleywine, 1999).
  • use of other psychoactive drugs (Vermeeren, 2004; Wadsworth et al., 2006)
  • psychosocial variables (Harbourg et al., 1993).
  • gender (women are more sensitive to alcohol even after adjusting for body weight)
  • total alcohol consumption divided by the time spent drinking.
  • type of alcohol (e.g., wine vs beer).

Hangover Theories

When Does The Fun End and The Hangover Begin?

Hangovers begin 6-8 h after your last drink when your blood alcohol concentration (BAC) is decreasing. Hangover symptoms peak when your BAC hits 0 and can last up to 24 hours.

Wiese et al. (2000) proposed evaluating hangover when there are two or more symptoms, after all alcohol is metabolized, and when BAC reaches 0.

There are some finicky researchers who think that hangover symptoms occur before the BAC reaches 0 (Kim et al., 2003a,b).

More studies are needed to tease apart the relationship between hangover timeline, BAC, and time of eating. Eating seems to reduce the intensity of hangovers – which makes scientific sense as we’ll see later.

What Causes a Hangover?

Many scientists have attempted to explain the hangover phenomenon. We’ll discuss the most well-known hypotheses. Most of them are half-truths; they’re partially correct but only part of the story.

Hangover as Alcohol Withdrawal

This is the theory that a hangover is actually the first phase of acute alcohol withdrawal (Swift and Davidson, 1998; Wiese et al., 2000).

Many hangover symptoms seem awfully similar to alcohol withdrawal symptoms. Let me give an example. Here are some overlapping symptoms between alcohol withdrawal and hangover:

  • headache
  • nausea
  • vomiting
  • sweating
  • anxiety
  • fatigue
  • wholesale discomfort
  • cognitive impairment It turns out that this theory is mostly incorrect. Here’s why.

McMicken (1990) describes three stages of alcohol withdrawal (minor, major, and delirium tremens). Delirium tremens is confusion brought on by alcohol withdrawal, and sometimes involves hallucinations.

According to these stages, hangovers can only be explained by the minor alcohol withdrawal symptoms which appear within 24h after your last drink. Remember that a hangover manifests a few hours after alcohol consumption and lasts for about 24h (sometimes longer).

Major withdrawal and delirium tremens occur 1–5 days after abstaining from alcohol. Both stages exhibit symptoms that are not typical of hangovers like hallucinations and seizures (Wiese et al., 2000).

While there is a resemblance between alcohol withdrawal and hangover, they are clearly not identical:

  • Some hangover symptoms like altered affect and cognition are absent in minor alcohol withdrawal.
  • Alcohol does reverse some hangover symptoms in addition to withdrawal symptoms (Swift and Davidson, 1998). But this only indicates a shared biological mechanism.
  • The biochemical changes during alcohol withdrawal differ from those observed in a hangover (Wiese et al., 2000).
  • Alcohol withdrawal requires alcohol chronic alcohol consumption yet you can get a hangover after just one bender (Fadda and Rossetti, 1998).
  • During a hangover, EEG activity slows down and there is a decrease in auditory threshold sensitivity (Jarvilehto et al., 1975; Sainio et al., 1976). Hence, people avoid loud noises during a hangover. But in contrast to a hangover, alcohol withdrawal makes the brain hyperexcitable and seizure-prone (Fadda and Rossetti, 1998). Hangovers occur more frequently in heavy drinkers (Kauhanen et al., 1997; Smith and Barnes, 1983). If you’re vulnerable to alcoholism (e.g., a family member is an alcoholic) you’re more likely to experience severe hangovers (Newlin and Pretorious, 1990; Span and Earleywine, 1999).

It’s clear that hangovers are a different phenomenon from withdrawal. Even so, it is possible to be both hungover and in a state of alcohol withdrawal at the same time!

The Acetaldehyde Theory of Hangovers

Alcohol is metabolized by two chemical reactions. First, alcohol (ethanol) is oxidized to acetaldehyde, which is further oxidized to acetic acid (that’s the acid in vinegar).

When you’re drinking acetaldehyde can begin to accumulate. Acetaldehyde causes unmistakable symptoms – the most famous of which is the “Asian flush”. Other symptoms include:

  • tachycardia
  • sweating
  • facial blushing
  • nausea
  • vomiting (Swift and Davidson, 1998). Quick aside: one treatment approach to alcoholism is to give alcoholics drugs that worsen this acetaldehyde buildup. The idea is that acetaldehyde accumulation is so unpleasant that it will deter you from drinking. Disulfiram is sometimes prescribed to alcoholics because it inhibits the metabolization of acetaldehyde (Kiefer and Mann, 2005). Rarely alcoholics drink despite taking disulfiram which is potentially life-threatening.

Could the Flush Syndrome Explain Hangovers?

If you take a look at the list of flush symptoms above there are similarities between hangover symptoms (e.g., tachycardia) and acetaldehyde poisoning. So maybe a buildup of acetaldehyde causes hangovers?

Several authors suggest that the acetaldehyde metabolite contributes to hangovers (Swift and Davidson, 1998; Wiese et al., 2000).

Protip: there’s some evidence that the supplement N-acetylcysteine helps the body eliminate acetaldehyde more quickly.

Even though researchers have pursued this hypothesis, the role of acetaldehyde in hangovers should be considered cautiously. Here’s why:

  • Many studies needed excess acetaldehyde to show the flush syndrome. They used amounts of acetaldehyde which overshot the acetaldehyde that accumulates naturally from drinking (Quertemont et al., 2005; Simonetta et al., 2006).
  • Although acetaldehyde contributes to hangover symptoms, it’s not present in the blood system or is not accumulated in the organism during hangover (Ylikahri et al., 1974). By the time that a hangover is in full swing, your body has eliminated most of the acetaldehyde. One author points out that we should think more carefully about the effect of acetaldehyde on brain function. That’s because alcohol is also metabolized in the brain (Quertemont et al., 2005), albeit to a much lesser extent compared with the liver. Smith speculates that alcohol metabolized to acetaldehyde in the brain could greatly alter central nervous system functioning (Smith et al., 1997).

Genetics of the Flush Syndrome

Genetic polymorphisms are linked to the enzyme that metabolizes acetaldehyde.

Some Asians convert alcohol to acetaldehyde too quickly, convert acetaldehyde to acetic acid too slowly, or both. This causes acetaldehyde to accumulate in their body after drinking (Quertemont et al., 2005; Simonetta et al., 2006).

Some researchers wondered whether there might be an evolutionary advantage to being alcohol intolerant. It might have a protective effect against alcoholism, for example. This idea remains speculative, but studies have found that abstainers and infrequent drinkers are more likely to be slow acetaldehyde metabolizers (Higuchi et al., 1994).

Do Poor Metabolizers Experience Worse Hangovers?

One study reported a greater susceptibility to hangovers in Asian subjects, suggesting a link between excess acetaldehyde and hangovers (Yokoyama et al., 2005). This study needs replication, but it hints that the inactive aldehyde dehydrogenase may have a protective effect against alcoholism by making hangovers intolerable.

Hangover As A Direct Effect of Alcohol

Why can’t alcohol itself cause hangovers? Why do we need to invoke some “additional thing” beyond the fact that ethanol is a toxic to explain the phenomena of a hangover?

Scientists indeed suggest that several hangover symptoms could be explained by a direct effect of ethanol on human physiology (Swift and Davidson, 1998; Wiese et al., 2000).

Consider these physiological effects of alcohol which are clearly linked to hangover:

  • electrolytic imbalance (drink Gatorade!)
  • gastric irritation
  • hypoglycemia (low blood-sugar; eat something)
  • sleep alterations (passing out and then waking up too early)
  • vasodilatation (widening of blood vessels; will make you dizzy on standing)
  • cytokine production (inflammatory mediators that rally the immune system when you’re infected) Why couldn’t these physiological effects of alcohol explain some hangover symptoms? I’m talking about symptoms like:


Alcohol has is a diuretic effect; it makes you want to urinate.

As your BAC approaches zero, you’re left dehydrated. Plasma levels of antidiuretic hormone [ADH](Vamvakas et al., 1998) become elevated – this is your body’s attempt to retain fluids in a hypovolemic state.

Antidiuretic (ADH) levels are correlated with hangover severity. This makes intuitive sense: the more you alcohol you drink the more dehydrated you become and the more ADH your body releases to compensate in order to retain fluids.

Gastrointestinal (GI) Distress

GI discomfort tends to occur after a bender rather than moderate indulgence in alcohol. This symptom is heavily influenced by the type of alcohol consumed (Linnoila et al., 1979).


Headaches are arguably among the worst hangover symptoms. So what causes a hangover-induced headache?

There are a few factors at play:

  • vasodilation
  • increased serotonin, histamine, and prostaglandin levels (Pattichis et al., 1995)
  • insufficient magnesium, which is reversed by IV MgSO4 (Altura and Altura, 1999)

Alcohol can also elicit cytokine release, which contributes to headaches. For example, alcohol increases thromboxane B2 levels which may explain other hangover symptoms in addition to headaches like nausea, diarrhea, and tiredness (Kangasaho et al., 1982).

Cytokines and Inflammation

What the hell is a cytokine?

Cytokine refers to an inflammatory molecule or protein like interferon or interleukin that are secreted by certain cells of the immune system.

During a hangover, cytokines line IL- 10, IL-12 and IFN-gamma increase (Kim et al., 2003b).

Reichenberg et al. (2001) note a correlation between cytokines and memory impairments in humans. Reversible cognitive impairment is another negative consequence of a hangover (Prat et al., 2008).

Elevated cytokine levels are related positively with the scores in a subjective hangover scale (Kim et al., 2003a). These data agree with the preventive effect on the hangover of tolfenamic acid, a prostaglandin inhibitor (Pittler et al., 2006).

In brief, cytokines and inflammation play a role in hangovers.


Hangovers go hand-in-hand with hypoglycemia (a drop in blood sugar).

If you’re otherwise perfectly healthy, the hypoglycemic effect of a hangover is modest or negligible.

But when glycogen stores are depleted (chronic alcoholics, subjects on a low-carbohydrate diet or in fasting people missing a meal while drinking), alcohol consumption leads to a hypoglycemic state (Siler et al., 1998). Glycogen is how sugar is stored in your liver. Glycogen is the reason you can fast for days without dying.

Alcohol is also able to induce reactive hypoglycemia (O’Keeffe and Marks, 1977). After a carbohydrate-rich meal combined with alcohol, the insulin response to rising blood glucose levels can be increased and leads to hypoglycemia 2–3 hours after a meal (O’Keeffe and Marks, 1977).

The drop in blood sugar could affect brain function since the brain requires a constant influx of energy. So alcohol-induced hypoglycemia can lead to a state of weakness, tiredness, and changes in mood observed during a hangover. But alcohol is usually mixed with low caloric soft drinks or meals and that which would offset this effect.

** Protip: if you’re hungover, have something simple to eat even if you don’t feel like. Something that won’t exacerbate nausea like a slice of plain bread. **

Sleep Deprivation

Alcohol is not good for sleep. Yet paradoxically, some people say they drink in the evening to help them fall asleep. How is this possible?

It’s true that alcohol reduces sleep latency (the time it takes to fall asleep). But as blood levels of alcohol fall, your sleep architecture becomes disrupted. Sleep architecture is just a neuroscience buzzword for the amount of time you spend in REM vs slow wave sleep, which are different sleep stages.

Drinkers spend less time in REM sleep, don’t synthesize as much melatonin in the evening, and their total time asleep is reduced.

These negative effects on sleep quality may explain some hangover symptoms, particularly cognitive impairment (Prat et al., 2008; Verster and Rohers, 2007).

All this goes to show that some hangover symptoms are because of the direct physiological effects of alcohol intake. Such effects include increased cytokines, electrolyte imbalances, sleep deprivation, hypoglycemia, and others.

Hangover as a Result of the Congener Effects of Alcoholic Beverages

This hypothesis says that hangover symptoms are due to the deleterious effects of compounds that are present in alcohol beverages. These compounds are called congeners (Calder, 1997).

Congeners tend to be amines, amides, acetones, polyphenols, methanol, and histamines. They’re created during the alcoholic fermentation or are added during production and are part of what makes the experience of drinking a pinot noir so different from a mojito.

Chapman (1970) discovered that one-third of the subjects that consumed 1.5 grams/kg of bourbon (which is rife with congeners) experienced a hangover. By contrast, only 3% of subjects that had the same dose of vodka got a hangover.

More recent surveys seem to confirm that hangover severity is greater in beverages including larger numbers of congeners (Vester, 2006).

Protip: drinking a low-congener alcohol like vodka reliably reduces next-day hangover symptoms.


Among the best-studied congeners is methanol.

Jones (1987) argues that hangovers are caused by metabolites of methanol, formaldehyde, and formic acid. These chemicals are more hazardous than acetaldehyde.

Here’s the evidence:

  • The metabolism of methanol is well-correlated with and recapitulates hangover symptoms (Bendtsen et al., 1998).
  • Beverages containing more methanol worsen hangover symptoms
  • Low-dose ethanol, which competes for the enzymes that degrade methanol and thus slows methanol metabolism, is a great treatment for a hangover (Calder, 1997). Some key point against this theory are that methanol has a short average life – it’s already gone by the time hangover symptoms emerge. Also, the ingestion of some alcoholic beverages like wine and specific liquors create quite low levels of methanol, and thus their pharma- sense effects are nearly nonexistent (Nathan et al., 1970). So other important congeners, like isopentanol, ethylic acetate, and ethyl formate may also play a role in hangovers (Vester, 2006).


The short and sweet version.

Surprisingly, there’s no “unified theory of hangovers” and no consensus on how to measure hangover severity

  • Tolfenamic acid, gamma-linoleum acid, and yeast are promising hangover remedies
  • Ways to reduce hangovers:
    • Drink the same amount of alcohol over a longer interval of time
    • Stay hydrated and replenish electrolytes (e.g., Gatorade)
  • Eat something even if you don’t feel it (low blood-sugar plays a big role in hangovers)
  • Sleep even if you feel alert. Alcohol may knock you out but your sleep quality will be impaired.

Another facet that is unrecognized is the potential differences of gender in a hangover.

Slutske et al. (2005) have noted that women are more vulnerable to both hangovers and the intoxicating effects of alcohol itself. Future research should look carefully into this since the data to be obtained would have prophylactic consequences of tremendous worth.


Delk EW, Meilman PW. 1996. Alcohol use among college students in Scotland compared with norms from the United States. J Am Coll Health 44: 274–281

Mallett KA, Lee CM, Neighbors C, Larimer MW, Turrisi R. 2006. Do we learn from our mistakes? An examination of the impact of negative alcohol-related consequences on college students’ drinking patterns and perceptions. J Stud Alcohol 67: 269–276.

Piasecki TM, Sher KJ, Slutske WS, Jackson KM. 2005. Hangover frequency and risk for alcohol use disorders: evidence from a longitudinal high-risk study. J Abnorm Psychol 114: 223–234.

Slutske WS, Piasecki TM, Hunt-Carter E. 2003. Development and initial validation of the hangover symptoms scale: prevalence and correlates of hangover symptoms in college students. Alcohol Clin Exp Res 27: 1442– 1450.

Wright NR. 1997. Breath alcohol concentrations in men 7–8 hours after prolonged, heavy drinking: influence of habitual intake. Lancet 349: 182.

McFarlin SK, Fals-Stewart W. 2002. Workplace absenteeism and alcohol use: a sequential analysis. Psychol Addict Behav 16: 17–21.

Ragland DR, Krause N, Greiner BA, Holman BL, Fisher JM, Cunradi CB. 2002. Alcohol consumption and incidence of workers’ compensation claims: a 5-year prospective study of urban transit operators. Alcohol Clin Exp Res 26: 1388–1394.

Swift R, Davidson D. 1998. Alcohol hangover. Mechanisms and mediators. Alcohol Health Res World 22: 54–60.

Wiese JG, Shlipak MG, Browner WS. 2000. The alcohol hangover. Ann Intern Med 132: 897–902.

Span SA, Earleywine M. 1999. Familial risk for alcoholism and hangover symptoms. Addict Behav 24: 121–125.

Vermeeren A. 2004. Residual effects of hypnotics: epidemiology and clinical implications. CSN Drugs 18: 297–328.

Harbourg E, Gunn R, Gleiberman L, DiFranceisco W, Schork A. 1993. Psychosocial factors, alcohol use, and hangover sings among social drinkers: a reappraisal. J Clin Epidemiol 46: 413–422.

McMicken DB. 1990. Alcohol withdrawal syndromes. Emerg Med Clin North Am 8: 805–819.

Fadda F, Rossetti ZL. 1998. Chronic ethanol consumption: from neuroa- daptation to neurodegeneration. Prog Neurobiol 56: 385–431.

Jarvilehto T, Laakso ML, Virsu V. 1975. Human auditory evoked responses during hangover. Psychopharmacology (Berl) 42: 173–177.

Sainio K, Leino T, Huttunen MO, Ylikahri RH. 1976. Electroencephalo- graphic changes during experimental hangover. Electroencephalogr Clin Neurophysiol 40: 535–538.

Kauhanen J, Kaplan GA, Goldberg DD, Cohen RD, Lakka TA, Salonen JT. 1997. Frequent hangovers and cardiovascular mortality in middle-aged men. Epidemiology 8: 310–314.

Newlin DB, Pretorious MB. 1990. Sons of alcoholics report greater hang- over symptoms than sons of nonalcoholics: a pilot study. Alcohol Clin Exp Res 14: 713–716.

Earleywine M. 1993b. Personality risk for alcoholism covaries with hang- over symptoms. Addict Behav 18: 415–420.

Quertemont E, Tambour S, Tirelli E. 2005. The role of acetaldehyde in the neurobehavioral effects of ethanol: a comprehensive review of animal studies. Prog Neurobiol 75: 247–274.

Ylikahri RH, Huttunen M, Eriksson CJ, Nikkila EA. 1974. Metabolic studies on the pathogenesis of hangover. Eur J Clin Invest 4: 93– 100.

Higuchi S, Matsuhita S, Imazeki H, Kinoshita T, Takagi S, Kono H. 1994. Aldehyde dehydrogenase genotypes in Japanese alcoholics. Lancet 343: 741–742.

Yokoyama M, Yokoyama A, Yokoyama T, et al. 2005. Hangover suscepti- bility in relation to aldehyde dehydrogenase-2 genotype, alcohol flushing and mean corpuscular volume in Japanese workers. Alcohol Clin Exp Res 29: 1165–1171.

Leave a Comment

Your email address will not be published. Required fields are marked *