What happens in your body when you drink?
Alcohol is a diuretic. It suppresses ADH — antidiuretic hormone — which normally controls how much fluid your kidneys reabsorb. When ADH is suppressed, your kidneys produce more urine than normal, sometimes up to four times more fluid than you're drinking. That's why you visit the bathroom so frequently on a night out.
But it's not just fluid. With every bathroom trip, electrolytes leave your body too — sodium, potassium, and magnesium. These minerals are critical for cells to function, nerves to fire, and muscles to contract. When they drop, you feel it as muscle cramps, fatigue, and headaches.
Meanwhile, your liver is working at full capacity. Alcohol is broken down via the enzyme alcohol dehydrogenase into acetaldehyde — a toxic metabolite that is then converted further into acetate. The liver prioritises that process above everything else, including regulating blood sugar. That contributes to the low-energy sluggishness you feel the morning after.
The problem with just drinking water
The logical reaction is to drink more water. And water is absolutely necessary — but it's not enough on its own. There's a physiological reason for this.
Your body needs more than fluid
When you drink large amounts of plain water without electrolytes, plasma osmolality — the concentration of dissolved substances in the blood — can drop. Your body interprets this as a fluid surplus and compensates by increasing urine production. Paradoxically, the result can be that you excrete more fluid than you take in, making dehydration at the cellular level worse rather than better.
Physiologically, the water you drink needs to be accompanied by electrolytes to actually stay in your system — sodium plays a role in the kidneys' fluid regulation, while potassium and magnesium are needed for normal cell and muscle function. That's the general physiology. Which of these we're allowed to communicate as health claims for HANGOVR GUARD's ingredients is governed separately by EU regulation — see the next section.
What the research and EU regulation say together
What your body needs after a night out comes down to three things: fluid balance, energy metabolism, and what's traditionally been used to support digestion. But what we're actually allowed to communicate about each ingredient is governed by EU health claim regulation — not by what sounds best in marketing. Here's the honest picture, ingredient by ingredient.
Electrolytes — the EU-approved claims
Magnesium citrate contributes to electrolyte balance and to the reduction of tiredness and fatigue — EU-approved health claims. Potassium citrate contributes to normal functioning of the nervous system and muscle function — also an approved claim. Sodium is an essential electrolyte and is included in the formula, but there is no EU-approved health claim for sodium, so we make none.
B-vitamins and energy metabolism
Alcohol impairs the absorption of B-vitamins, and B1 (thiamine) is particularly sensitive. Thiamine contributes to normal energy-yielding metabolism — an EU-approved health claim (Regulation 432/2012). When levels drop after a night of drinking, that's a documented physiological mechanism.
Alcohol also depletes the body's vitamin C reserves. Vitamin C contributes to the reduction of tiredness and fatigue — the EU-approved health claim we use, at 80mg per serving.
Milk thistle and prickly pear — what EU regulation allows us to say
Milk thistle (silymarin) is a traditional herbal extract with a long history in herbal medicine, listed in the European Pharmacopoeia. Prickly pear extract (Opuntia ficus-indica) has a similar history. Both have "on-hold" status with EFSA — no health claim is approved for marketing within the EU, and an April 2025 ruling tightened practice around exactly this type of botanical claim further. That means we don't write that they "support the liver" or similar, however common that is among other brands. We include them as traditional herbal extracts, at doses consistent with traditional use — and nothing more.
Summary
- →Alcohol suppresses ADH → body loses more fluid and electrolytes than normal
- →Plain water without electrolytes can increase urination further — counterproductive
- →Vitamin B1 (thiamine) is depleted by alcohol — contributes to normal energy metabolism (EU-approved claim)
- →Milk thistle and prickly pear are EFSA "on-hold" — traditional herbal extracts, no effect claims
Frequently asked questions
Why am I still thirsty even after drinking lots of water? +
Alcohol suppresses ADH, causing the kidneys to excrete more fluid than normal. Drinking large amounts of plain water without electrolytes can also lower plasma osmolality, signalling the body to increase urination further. The fluid passes through without restoring balance at the cellular level. Your body needs sodium, potassium, and magnesium to actually retain the water you drink.
What does B-vitamin have to do with a night out? +
Alcohol impairs the absorption of B-vitamins, particularly B1 (thiamine). Thiamine plays a key role in how cells convert nutrients into energy — an EU-approved health claim. When levels drop after drinking, it directly contributes to the mental fog and sluggishness the next morning.
What is milk thistle and why is it relevant? +
Milk thistle (Silybum marianum) is a traditional herbal extract listed in the European Pharmacopoeia, with a long history in herbal medicine linked to liver and gallbladder complaints. EFSA classifies it as "on-hold" — no health claim is approved in the EU. Milk thistle extract 200mg is included in HANGOVR GUARD's formula as a traditional herbal extract, without effect claims.