If you’ve ever had a migraine, this probably won't come as a surprise to you: Everybody’s migraine triggers are different, says a new study published in the journal Cephalalgia.

If you’ve never had a migraine, count yourself very, very lucky—both medically and statistically. Migraine is the third most common illness in the world; in America, it affects someone in nearly one out of every four households. And the symptoms go well beyond a bad headache; for many people, migraine attacks cause extreme light and sound sensitivity, nausea, vomiting, and facial tingling or numbness. The effects are so debilitating that more than 90 percent of sufferers report being unable to work or function normally once a migraine hits.

What sets off a migraine? That’s the million-dollar question. If we can identify migraine triggers, we might be able to help people eliminate or at least avoid them. But doing so has proven to be tricky. Previous studies of large groups of migraine patients identified a list of common triggers, but it’s a long list, and there was no evidence that the most common triggers affected people the same way.

An international team of researchers decided to find out just how unique each person’s triggers are. They compiled information from 326 migraine patients, each of whom had kept a diary for 90 days, noting when they experienced any of the 33 most common triggers or hints a migraine was coming. Using the diary data, researchers were able to generate trigger profiles for 87 percent, or 283, of the participants.

In analyzing those profiles, the researchers found that the so-called common triggers weren’t really very common at all. Only eight of the top 33 appeared to trigger migraines, and 85 percent of the 283 participants were unique in their trigger profiles. That is, the combination of things that could potentially set off their migraines were unique.

On top of that, they found that people prone to migraines didn’t have one trigger, or two. On average, they had four. That’s four incredibly common things—like caffeine, stress, poor sleep, cheese, alcohol, or neck pain—that each person has to avoid. There’s nothing fun about migraine prevention, but it is infinitely more fun than actually having a migraine.

Christian Wöber leads the headache department at MedUni Vienna's Department of Neurology. "For the very first time,” he said in a press statement, “this new analysis therefore provides information about the correlation between migraine attacks and a broad spectrum of possible trigger factors for each individual patient and is therefore a step towards personalized migraine management."

Like so many medical studies, this one comes with a big caveat. One of the paper’s authors, Stephen Donoghue, is the vice president of clinical research at Curelator, a company that sells a $50 app that tracks migraine triggers. (Some neurologists may also offer it to their patients for free.) There’s no doubt that identifying your migraine triggers is a good thing, but these results should nevertheless be taken with a grain of salt.