Red wine headache, or RWH, has long been a subject of contention. Contrary to popular belief, it isn't caused by sulfites (both sweet white wines and dried fruits contain more sulfites than red wine), but rather compounds found in grape skins. Still, no single chemical has conclusively proven to be the culprit.
Some believe the cause is a group of chemicals, which include tyramine, histamine, and others. Red wine contains higher levels of these, because it's produced using the grape's skin and juice. Other scientists theorize that tannins, another byproduct of grape skins, could be at fault. Still others point to lipid compounds. These potential culprits vary among red wines. If you aren't ready to give up red wine just yet, experts suggest trying a small glass of different brands and varietals — like less-tannic Burgundies, Riojas, and Pinot Noir — then noting whether they cause a headache, which would likely appear within 15 minutes.