Hangover Science: Prevention & Recovery

A hangover is your body communicating clearly that it processed more alcohol than it could comfortably handle. Understanding the mechanisms involved is the most honest path to preventing them.

What Actually Causes a Hangover

Dehydration

Alcohol is a diuretic — it suppresses antidiuretic hormone (ADH), causing your kidneys to excrete more water than you are taking in. For every alcoholic drink, you may urinate an extra 100–150 ml beyond what you consume. This fluid loss from blood volume, tissues, and cerebrospinal fluid accounts for the headache, dry mouth, and fatigue.

Congeners

Congeners are by-products of fermentation and ageing — acetaldehyde, methanol, tannins, fusel oils, and other compounds found in varying quantities in different spirits. Dark spirits (whisky, rum, brandy, dark tequila) contain significantly more congeners than clear spirits (vodka, gin, silver tequila). This is why, at equivalent alcohol doses, many people find dark spirits produce worse hangovers.

Methanol, a congener in many fermented drinks, metabolises to formaldehyde — it is present in tiny quantities in most alcoholic drinks and its contribution to hangovers is genuine, though modest.

Acetaldehyde Accumulation

Your liver converts ethanol to acetaldehyde (toxic), then to acetate (harmless) via the enzyme ALDH. When you drink faster than your liver can process, acetaldehyde accumulates — causing nausea, sweating, and a racing heart. Some people (particularly of East Asian heritage) have a genetic variant that reduces ALDH activity, making acetaldehyde accumulation more pronounced.

Blood Sugar Disruption

Alcohol inhibits gluconeogenesis — the liver's ability to produce new glucose. Heavy drinking can lead to hypoglycaemia, contributing to weakness, shakiness, and mood disruption the morning after.

Sleep Disruption

Alcohol may help you fall asleep faster, but it fragments sleep architecture. REM sleep is significantly suppressed, leading to poor sleep quality even if total hours seem adequate. This explains the grogginess that persists even after a full night's rest.

Immune Response and Inflammation

Recent research points to an inflammatory response as a significant contributor to hangover symptoms. Cytokine production increases after heavy drinking, contributing to the achiness, cognitive fog, and malaise.

Evidence-Based Prevention

During drinking:

• Eat before and during — food slows alcohol absorption significantly, especially fats and proteins
• Alternate with water — one glass of water per alcoholic drink meaningfully reduces dehydration
• Pace yourself — your liver processes approximately 1 standard drink per hour; exceeding this leads to accumulation
• Choose lighter congener drinks — if choosing between a dark rum and a vodka cocktail, the vodka will typically produce a milder morning

Before bed:

• Electrolytes — a glass of water with an electrolyte tablet or a sports drink replaces sodium, potassium, and magnesium lost through diuresis
• Eat something — helps stabilise blood glucose through the night

What does not work: coffee (worsens dehydration), "hair of the dog" (delays processing and risks dependence), greasy food consumed the morning after (it helps before, not after).

Morning-After Recovery Drinks

The goal is rehydration, electrolyte replenishment, and gentle blood sugar restoration.

Electrolyte Water: - 500 ml water - Pinch of sea salt (sodium) - Squeeze of lemon (flavour and mild citric acid) - 1 tsp honey (glucose, potassium) - Optional: electrolyte tablet

Coconut Water — naturally contains potassium, magnesium, and sodium. One of the better natural electrolyte drinks.

Ginger Tea — ginger has demonstrated anti-nausea properties. Steep fresh ginger slices in hot water for 10 minutes. Add honey to taste.

Tomato Juice — contains sodium, lycopene, and vitamin C. The Bloody Mary's reputation as a hangover cure is almost entirely attributable to its vegetable juice base (and the hair-of-the-dog component).

Banana Smoothie — bananas are rich in potassium and provide quick glucose. Blend with cold milk (electrolytes) and a teaspoon of honey.

The Honest Answer

The most effective hangover prevention is drinking less. There is no supplement, food, or ritual that fully offsets the physiological impact of excess alcohol. The strategies above reduce severity at the margins — they do not eliminate it.

Knowing the science helps you plan better: eat well before going out, hydrate consistently during the evening, choose your drinks thoughtfully, and look after yourself before sleep. These modest steps make a genuine difference.