The Science of Hangovers: Why You Feel Like That (and How to Actually Prevent One)
You wake up at 7am when you wanted to sleep until noon. Your mouth tastes like a carpet. Your head is doing something that should not be legal. You're simultaneously too hot and too cold. You stare at the ceiling and make promises to yourself that you will absolutely break within the next three weeks.
Hangovers are one of the most universally experienced miseries in human social life, and yet the science behind them is surprisingly misunderstood. Most people blame dehydration alone, or the alcohol itself, or "mixing" different types of drinks. The actual picture is more complicated and, crucially, more actionable — because once you understand the real mechanisms, you can actually do something about them.
This is that explanation. No bro science, no folk remedies presented as fact. Just the actual biology of what alcohol does to your body and a clear breakdown of what the evidence says actually helps.
What a Hangover Actually Is
A hangover isn't one thing — it's a cluster of symptoms caused by several simultaneous physiological insults. Understanding each one helps you understand why the popular remedies work (or don't).
1. Dehydration and Electrolyte Loss
Alcohol suppresses a hormone called ADH (antidiuretic hormone, also called vasopressin), which is responsible for telling your kidneys to retain water. With ADH suppressed, your kidneys excrete far more water than they receive from your drinks. Research published in the British Journal of Nutrition has found that for every alcoholic drink consumed, the body loses approximately 100–150mL of additional urine beyond normal output — which means a night of four or five drinks could leave you 500–750mL more dehydrated than if you'd had nothing at all.
But it's not just water you lose. With that extra fluid, you excrete electrolytes: sodium (which regulates fluid balance in cells), potassium (essential for nerve and muscle function), and magnesium (involved in over 300 biochemical reactions including sleep regulation and energy metabolism). Magnesium deficiency specifically is associated with headaches, muscle cramps, and the "foggy" cognitive feeling that makes a hangover morning so unpleasant.
This is why hydrating cocktails that include electrolytes, like those made with OFTN mix, genuinely help — not as a cure, but as a prevention that runs parallel to drinking.
2. Acetaldehyde Accumulation
When your liver metabolizes alcohol (ethanol), the first byproduct it produces is acetaldehyde, a toxic compound that is estimated to be roughly 10–30 times more toxic than the alcohol itself. Under normal circumstances, an enzyme called ALDH2 quickly converts acetaldehyde into acetate (a harmless compound similar to vinegar). But when you drink faster than your liver can keep up, acetaldehyde accumulates in your bloodstream.
Acetaldehyde is responsible for many of the worst hangover symptoms: nausea, sweating, rapid heartbeat, and the general "poisoned" feeling. This is also why people who have a genetic variant that reduces ALDH2 activity — common in East Asian populations — experience facial flushing and intense nausea from even small amounts of alcohol. Their bodies accumulate acetaldehyde more rapidly than most.
3. Inflammation and Immune Response
Alcohol triggers a genuine inflammatory response. Research published in PLOS ONE found that alcohol consumption elevates cytokines — inflammatory signaling proteins — in the bloodstream. Many of the classic hangover symptoms, including achiness, fatigue, loss of appetite, sensitivity to light and sound, and cognitive impairment, are consistent with a mild systemic inflammatory response. This is the same mechanism that makes you feel terrible when you're sick — your immune system is reacting to something it perceives as a threat.
4. Blood Sugar Disruption
Alcohol interferes with your liver's ability to maintain blood glucose levels. Normally, when your blood sugar drops, the liver releases stored glucose (glycogen) to stabilize it. Alcohol impairs this process by diverting liver resources to metabolizing ethanol instead. The result can be reactive hypoglycemia — low blood sugar — which contributes to shakiness, sweating, weakness, and the intense carbohydrate cravings that make morning-after pizza so appealing.
5. Sleep Architecture Disruption
Alcohol is famously a sedative — it makes you fall asleep faster — but it significantly impairs sleep quality. Research from the Journal of Clinical Sleep Medicine consistently shows that alcohol suppresses REM sleep (the stage associated with memory consolidation, emotional regulation, and cognitive restoration) and causes fragmented, shallow sleep in the second half of the night as the alcohol metabolizes. This is why you can sleep for eight hours and still feel exhausted after drinking — the hours you logged weren't restorative hours.
6. Congeners
Congeners are byproduct compounds produced during fermentation and aging: methanol, acetone, acetaldehyde, tannins, and esters. Darker spirits — bourbon, whiskey, brandy, dark rum, red wine — have significantly higher congener content than clear spirits like vodka, gin, and white rum. Research published in the British Medical Journal found that bourbon produced significantly worse hangovers than the same amount of vodka, despite equal alcohol content, due to congener load. This is the closest thing to a scientific basis for the "mixing drinks gives you worse hangovers" belief — it's not the mixing, it's the congeners in the darker drinks.
What Doesn't Work (Despite What You've Heard)
"Hair of the dog" (drinking more alcohol to cure a hangover) works only in the narrowest technical sense: alcohol slightly suppresses hangover symptoms by delaying acetaldehyde metabolism. What it actually does is delay the hangover, not prevent it. The debt comes due later and usually with interest.
Greasy food before bed does not absorb alcohol or neutralize it. Fat does slow gastric emptying, which can slow the rate at which alcohol enters your bloodstream — but eating a big meal before you start drinking is the helpful version of this. Greasy food after you've already been drinking all night has minimal impact on what's happening in your bloodstream.
Coffee relieves the drowsiness component of a hangover by blocking adenosine receptors, but it is also a diuretic that may worsen dehydration. The net effect for most people is neutral to slightly negative from a recovery standpoint, though the alertness benefit can feel meaningful.
Sweating it out in exercise or a sauna may actually make things worse in the early stages, by increasing dehydration before you've restored fluid and electrolyte balance. Light movement after proper rehydration is a different story.
What Actually Works
Before drinking: Eat a proper meal containing fat and protein, which slows alcohol absorption. Drink a full glass of water before your first drink.
While drinking: This is the highest-leverage intervention point. Alternate alcoholic drinks with water. Choose lighter-colored spirits to minimize congener exposure. Use cocktail mixers that contain electrolytes — like OFTN mix — so that every drink is also partially replenishing what you're losing. Drinks made with our Watermelon Margarita, Yuzu Ginger Mule, or Pineapple Mimosa mixes include electrolytes and B vitamins by design, not as an afterthought. See our full guide to hydrating cocktails for more on this approach.
Before bed: Drink 16–24oz of water with electrolytes. This is the single most impactful thing you can do that you probably aren't doing. Even a basic sports drink before sleep meaningfully reduces next-morning symptoms compared to no fluid intake.
The morning after: Rehydrate with electrolytes first — before coffee, before greasy food. Eggs (which contain cysteine, an amino acid that supports acetaldehyde metabolism), bananas (potassium), and toast (blood sugar stabilization) are genuinely useful. NSAIDs like ibuprofen can help with headache and inflammation but should be taken with food and avoided if you have a sensitive stomach from the night before. Acetaminophen (Tylenol) should be avoided after heavy drinking, as both alcohol and acetaminophen are metabolized by the liver and the combination can be harmful.
Time: Most hangover symptoms resolve within 24 hours as acetaldehyde is cleared, electrolytes are restored, and sleep debt catches up. There is no true cure — only better or worse management of the process.
The Real Prevention Strategy
The most effective hangover prevention isn't a pill you take or a food you eat — it's drinking the right way throughout the evening. That means pacing yourself, staying hydrated with electrolytes throughout (not just at the end), choosing cleaner spirits, eating before you start, and not treating the hangover as something that happens to you but as a predictable set of biological processes you can partially intervene in.
That's the premise behind OFTN. We built our mixes to work while you drink, not as a cure you reach for the next morning. Every sachet contains electrolytes and B vitamins calibrated to partially offset what alcohol depletes — so you can enjoy genuinely good cocktails and wake up functional. Celebrate now. Feel good tomorrow.
