Electrolytes (oral rehydration)
Sodium is the one that matters, and it's the one most 'electrolyte' products under-dose in favour of a long label. Fixes a real part of a hangover — just not the part that makes you feel worst.
Rehydration itself is well established — oral rehydration therapy is one of the best-evidenced interventions in medicine. What is NOT established is that it treats a hangover: dehydration is a contributing mechanism, not the primary one, and correcting it addresses the thirst-and-dizziness cluster while leaving the inflammatory component untouched. Fast: 30–60 minutes for the symptoms it does fix.
Alcohol suppresses vasopressin, so you excrete more water than you take in, and you lose it as dilute urine — meaning you lose proportionally more water than salt. Replacing it with plain water alone dilutes what sodium you have left and much of it goes straight back out; replacing it with a sodium-containing solution retains far better, which is the entire principle behind oral rehydration therapy. That makes sodium the electrolyte that does the work here. Potassium and magnesium losses in a single night of drinking are modest and rarely the limiting factor, despite being the two most heavily marketed. Get the honest expectation right: rehydration reliably fixes thirst, dry mouth, dizziness on standing and part of the headache, and it does approximately nothing for the inflammatory, immune and sleep-related components — which is why people who drink a litre of electrolyte solution before bed still wake up feeling awful, just less parched. It is worth doing because it is cheap, safe and fast, not because it is a cure.
Key studies
- Do hangover IVs work? (University of Rochester Medical Center) — Included because the IV-drip industry is built on the opposite claim. Clinical view: an IV does not rehydrate you better than drinking, and there is no evidence it speeds hangover recovery. IV fluid is for people who cannot keep liquid down — that is a real indication, and it is not most Sunday mornings.
- Form
- Any sodium-forward oral rehydration product, or make it: 1 litre water + ~1/2 tsp table salt + a squeeze of juice. Commercial sachets (LMNT, Liquid IV, DripDrop) differ mostly in sodium content and price; the WHO oral rehydration formula is the reference and costs pennies.
- Dose
- 500 ml–1 litre with roughly 500–1,000 mg sodium, before bed and again on waking. More is not better — you are replacing a deficit, not loading.
- Timing
- Before bed is the highest-value moment; on waking is second. Sipping through the night beats one large glass, which mostly becomes urine.
- Schedule
- As needed. Not daily.
- Side effects
- Nausea if you drink it too fast. Excess sodium causes bloating and thirst of its own.
- Interactions
- Antihypertensives and heart-failure medication — a sodium load is not neutral if you are on either.
- Contraindications
- Hypertension, heart failure, kidney disease — talk to your doctor before treating salt as free. Potassium supplements are the genuinely risky one: hyperkalaemia is dangerous, and it is easy to reach with supplements where it is nearly impossible with food.
- Lab markers
- Sodium, potassium and creatinine if you have any reason to be watching them.
- Food sources
- Salted broth, miso soup, pickle juice, tomato juice, coconut water (potassium-heavy, sodium-light — not the best choice here). Broth is the most useful thing in this list.
Pairs with
Water, obviously, but salted. Magnesium and potassium are optional here rather than essential. See the hangover guide for how much of the morning this actually solves.
within Minerals