Hangover

Hangover — also known as alcohol hangover, or, medically, as veisalgia — is defined by the Alcohol Hangover Research Group as “the combination of negative mental and physical symptoms which can be experienced after a single episode of alcohol consumption, starting when blood alcohol concentration (BAC) approaches zero”.^[1] Specific symptoms are not listed due to the variability in how individuals experience hangovers. However, the presence of hangover symptoms, regardless of their nature, is often sufficient to disrupt the performance of daily tasks and responsibilities.

Over 47 symptoms of hangover have been identified. While many hangover symptoms are common, there is immense variation in the subjective experience of hangover: people with hangover may experience any of the hangover symptoms, or any combination of them, to any degree. Among the most common symptoms of hangover are fatigue, thirst, drowsiness, headache, and problems with concentration and memory.^[2]

Physical signs of hangover may include tachycardia (rapid heartbeat), increased blood pressure, tremor, sensitivity to noise and light, and muscle cramps. Sleep disturbances, including an increase in slow-wave sleep and a decrease in both rapid eye movement (REM) sleep and total sleep time, are also associated with hangover.^[3]

There currently is no objective assessment or biomarker that can be used to reliably “diagnose” hangover or to determine the severity of hangover symptoms. Thus, the diagnosis of hangover relies on the subjective reporting of symptoms. Three commonly-used hangover symptom scales include the Hangover Symptom Scale (HSS), the Acute Hangover Scale (AHS), and the Alcohol Hangover Severity Scale (AHSS). Each scale asks participants to rate the presence or absence of a variety of hangover symptoms, along with their severity (typically on a 0–10 scale).^[4]

Alternatively, research has suggested that a 1-item score — rating hangover from absent (0) to extreme (10) — may be more effective for accurately “diagnosing” and assessing the severity of hangover by encompassing all of the individual symptoms experienced by the drinker and their perceived impact on daily activities, mood, and function.^[4]

It is public consensus that abstaining from, or moderating, alcohol consumption is the main way to prevent a hangover, and the passage of time is the main way to alleviate it. Medical professionals should inform individuals that if they drink alcohol, they should do so within safe drinking limits; they should also provide clinically-appropriate screening for the diagnosis of suspected alcohol use disorder.^[5] So far only one medication has shown some benefit for hangover in clinical research — tolfenamic acid (brand names: Clotam, Tufnil), which is a nonsteroidal anti-inflammatory drug used in the treatment of migraine headache. However, the evidence is only very-low-certainty,^[5] and this medication is neither prescribed nor indicated for this purpose.

Drinking water with or without electrolytes, eating a snack, taking over-the-counter pain-relief medications, and going to sleep are also common advice to reduce hangover symptoms. Remarkably, common pain-relief medications like aspirin and acetaminophen have not been studied for hangover symptoms in clinical trials;^[5] however, the product SJP-001, a combination of naproxen and fexofenadine (an antihistamine), was shown to improve hangover severity compared to placebo in a small study.^[6]

Despite the high demand and potential productivity-saving applications of hangover treatments, there is currently a lack of evidence to support any such remedies. Though several different supplements and herbal compounds have been studied for their ability to reduce hangover symptoms, most have very little research to support their efficacy. A systematic review published in 2022 concluded that some supplements may reduce hangover symptoms compared to placebo. These include clove extract, pyritinol (a chemically-altered vitamin B6), Hovenia dulcis fruit extract, L-cysteine, red ginseng, and Korean pear juice. However, the evidence to support any of these supplements was rated as very low quality^[5], mostly due to a lack of well-controlled studies.

Despite the commonly-held belief that eating bread or greasy food will help to prevent a hangover by “soaking up” the alcohol, there’s no scientific evidence to support this effect. However, eating food (especially high-energy meals) before or during a drinking episode will help to mitigate the rate and magnitude of the rise in BAC, decrease the absorption of alcohol, and slow the metabolism of alcohol — leading to less intoxication and perhaps a less-severe hangover. Dietary intake of nicotinic acid and zinc is known to play a role in the metabolism of alcohol (ethanol) into acetaldehyde. Studies have found that social drinkers with higher intakes of zinc and nicotinic acid have a lower hangover severity. The intakes of other nutrients, including fat, carbohydrates, protein, fiber, salt, or vitamins B, D, C, and E, are not associated with hangover severity.^[7]

Recent treatments for hangover have targeted the inflammation- and oxidative stress-inducing effects of alcohol, although much more research is needed to know if these products help hangover, as the current evidence is limited. A product containing the amino acid L-cysteine along with B and C vitamins failed to improve hangover severity or associated biomarkers compared to placebo.^[8] Simple carbohydrates and Vitamin B6 have also shown some effectiveness for treating cognitive symptoms and hangover symptom severity, respectively.^[9]

Contrary to popular belief, drinking more alcohol does not cure a hangover.

It’s a popular yet unproven belief that dehydration is one of the main causes of hangover. While dehydration can contribute to symptoms of a hangover, it may not be the cause of hangovers per se — see below.

Rather, hangover seems to be the result of the direct effects of alcohol (ethanol) on the production of reactive oxygen species (ROS) — which are generated during the breakdown of alcohol. ROS elicit mitochondria damage and oxidative stress throughout the body and central nervous system (CNS). ROS also activate the immune system, initiating both pro- and anti-inflammatory cytokine responses in the body and CNS. Symptoms such as nausea, vomiting, headache, confusion, tremor, and learning and memory deficits occur in the presence of elevated levels of inflammatory cytokines, and higher levels of inflammation and ROS are associated with a greater hangover severity, directly implicating them in the pathology of hangover.^[10]

Other factors contributing to hangover include: an alteration in neurotransmitters such as GABA, glutamate, dopamine, serotonin, and the endocannabinoids; disturbances in sleep quality or quantity due to alcohol consumption; and alterations in hormones and electrolytes.^[11]