Why does red wine give you a headache?
Quick answer
Red wine contains high levels of histamine, tannins, and quercetin glucuronide — three substances that promote headaches. Histamine causes cerebral vasodilation, tannins trigger serotonin release, and quercetin blocks the ALDH2 enzyme, leading to acetaldehyde build-up.
Detailed answer
The headache after drinking red wine is so common it has a name in medical literature: RWH (Red Wine Headache). Unlike a hangover headache (which hits the next morning), RWH can appear within 30 minutes to 3 hours of drinking, even after just one glass.
The most recent breakthrough comes from a UC Davis study (Devi et al., Scientific Reports, 2023). Researchers identified quercetin-3-glucuronide as a potent inhibitor of the ALDH2 enzyme (aldehyde dehydrogenase 2). This enzyme normally metabolises acetaldehyde, a toxic byproduct of ethanol. When blocked, acetaldehyde accumulates in the blood, causing headaches, nausea, and flushing — the same symptoms experienced by people of East Asian descent who naturally have ALDH2 deficiency.
Quercetin is a flavonoid found primarily in red grape skins, with levels varying 1-10 fold depending on grape variety, sun exposure, and vineyard practices. More sun-exposed grapes produce more quercetin.
Other contributing factors include: histamine (3-4 times higher in red than white) causing cerebral vasodilation; tannins triggering serotonin release, whose fluctuations spark migraines; and dehydration from alcohol's diuretic effect making everything worse.
People prone to RWH can try reducing symptoms by drinking a large glass of water before and after each glass of wine, taking an antihistamine (on medical advice) 30 minutes before drinking, or choosing light, low-extraction red wines (Pinot Noir, Gamay) over heavily tannic reds.
The 5 causes of red wine headache
- Quercetin glucuronide: blocks the ALDH2 enzyme, causing acetaldehyde build-up (UC Davis 2023 study)
- Histamine: cerebral vasodilator, 3-4 times more concentrated in red than white
- Tannins: trigger serotonin release, whose fluctuations spark migraines
- Dehydration: alcohol's diuretic effect causes water and electrolyte loss
- Biogenic amines (tyramine): vasoconstriction followed by reactive dilation