They didn't find whether it was actually the source of the headaches, but only proposed a new hypothesis. The linked paper is a review, which proposes a novel h

They didn't find whether it was actually the source of the headaches, but only proposed a new hypothesis. The linked paper is a review, which proposes a novel hypothesis on red wine's mechanism of causing headache, and suggests that an experiment should take place to test the hypothesis. Many papers have previously suggested alternative ideas on why red wine causes headaches. Other hypothesises that I'm aware of is that the headaches are likely caused by histamine or tannins in red wine.