The phrase “hair of the dog” (HOD) refers to the folk remedy of consuming more alcohol to alleviate hangover symptoms. This belief suggests that drinking a small amount of the same substance—like a Bloody Mary or a morning beer—will neutralize the lingering effects. The expression originated from the ancient practice of treating a rabid dog bite by placing some of the dog’s hair into the wound. We will examine the neurochemical and metabolic reasons why this method appears to work in the short term, and why science advises against it in the long run.
Why the Morning Drink Provides Temporary Symptom Masking
The temporary relief provided by a morning drink is a pharmacological effect on the brain’s neurotransmitter balance. Alcohol’s initial calming effects occur because it acts on the gamma-aminobutyric acid (GABA) system, the brain’s main inhibitory network. Alcohol enhances GABA receptors, putting a brake on nerve cell activity and causing the relaxed feeling of intoxication. Simultaneously, alcohol blocks glutamate, the brain’s primary excitatory neurotransmitter, further reducing overall brain activity.
The brain strives to maintain equilibrium and compensates for alcohol’s suppressive effects by downregulating GABA function and increasing glutamate sensitivity. When alcohol is cleared from the system, this compensatory mechanism remains in overdrive, resulting in a glutamate rebound effect. This sudden spike in excitatory activity causes classic hangover symptoms, including anxiety, tremor, and rapid heart rate. The “hair of the dog” drink introduces more alcohol, which immediately re-stimulates the GABA system and temporarily suppresses the glutamate rebound, masking the withdrawal-like symptoms. This brief respite is temporary, not a sign of actual recovery, as the underlying chemical imbalance remains.
How More Alcohol Affects Toxin Processing
The perceived benefit of the morning drink is misleading because it interrupts the body’s essential detoxification process. Ethanol is metabolized in a two-step process, beginning with the enzyme alcohol dehydrogenase (ADH). ADH converts ethanol into acetaldehyde, a compound more toxic than ethanol itself. Acetaldehyde is responsible for severe hangover symptoms, including nausea, flushing, and a rapid pulse.
A second enzyme, aldehyde dehydrogenase (ALDH), is then needed to quickly break down the toxic acetaldehyde into the less harmful compound, acetate. When a person drinks more alcohol during a hangover, the liver diverts resources to processing the new ethanol load. This action slows the elimination of existing acetaldehyde from the initial drinking session. Introducing new alcohol delays the overall metabolic process, extending the presence of the toxic byproduct and prolonging recovery.
Another factor is the presence of methanol, a congener found in small amounts in most alcoholic beverages. Methanol is metabolized into formaldehyde, a highly toxic substance that contributes to hangover severity. The body’s enzymes prefer to process ethanol over methanol, so a new dose of ethanol temporarily delays the conversion of existing methanol into its toxic metabolite. While this mechanism temporarily alleviates some symptoms, it pushes the final resolution of the hangover further into the future.
Evidence-Based Hangover Recovery Methods
Since time is the only definitive cure for a hangover, effective strategies focus on managing symptoms and supporting natural recovery.
Rehydration and Rest
One important step is aggressive rehydration, as alcohol acts as a diuretic, leading to fluid and electrolyte loss. Sipping water, fruit juice, or electrolyte-rich sports drinks helps restore the fluid balance that contributes to headaches and fatigue. Bouillon soup is also beneficial, as it provides water and replaces lost sodium and potassium.
Rest is non-negotiable, as alcohol disrupts the normal sleep cycle. Allowing for extra sleep gives the brain and body time to repair tissues and clear remaining toxins. Supporting blood sugar levels is also helpful, since alcohol consumption can lead to mild hypoglycemia. Eating a breakfast that includes simple carbohydrates, like toast or crackers, can help stabilize blood sugar and mitigate weakness and nausea.
Pain Management
For headache and muscle aches, nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen are effective pain relievers. Caution is advised, as NSAIDs can irritate the stomach lining, which may already be inflamed by alcohol. Avoid acetaminophen, found in many common pain relievers, because when combined with alcohol, it increases the risk of serious liver damage.