Sorting the research on caffeine’s relationship to headaches can give you a headache, literally. While some studies suggest that caffeine triggers migraines, caffeine is also a popular treatment for headaches. These seemingly contradictory effects can muddy the waters on how to advise patients about their beloved morning brew. 

 

Caffeine as a migraine trigger

 

Every day, about 80% of the world’s population consumes some form of caffeine, according to an article in Nutrients.

Nowaczewska M, Wiciński M, Kaźmierczak W. The ambiguous role of caffeine in migraine headache: from trigger to treatment. Nutrients. 2020;12(8):2259. 

Unfortunately, 1 in 20 adults experience some form of headache every day, with migraines afflicting at least 1 in 7 adults, globally.

Headache disorders: How common are headaches? World Health Organization. February 11, 2014.

Migraines aren’t just a typical headache—they are a significant source of lost productivity and quality of life for over a billion people around the globe.

 

Researchers examining NHANES data from almost 9,000 adult participants identified a 5% uptick in migraines or severe headaches for every additional 100 milligrams of caffeine consumed per day.

Zhang L, Yin J, Li J, et al. Association between dietary caffeine intake and severe headache or migraine in US adults. Sci Rep. 2023;13(1):10220.

 

In a review of 21 studies, the researchers writing in Nutrients found that between 2.4% and 30.0% of participants reported caffeine as a trigger for their migraines. Caffeine withdrawal was also a common trigger, affecting 10% to 30% of those surveyed. However, the National Headache Foundation cites a much lower proportion of people with caffeine-withdrawal headaches—just 2% of “caffeine rebound headaches” were associated with withdrawals.

Does caffeine trigger or treat headaches?. National Headache Foundation. 2023.

 

Caffeine has multiple effects on the body that may affect headaches and migraines, note the researchers who evaluated the NHANES data. It inhibits excitatory neurotransmitters by acting as an antagonist to adenosine, and it modulates the action of dopamine. 

Caffeine intake or withdrawal affects cerebral blood flow and the central nervous system. It’s also possible that caffeine’s diuretic effects promote dehydration and the likelihood of headaches. As a result, the National Headache Foundation recommends avoiding daily caffeine intake for those who experience frequent headaches.

 

Treating headaches with caffeine

 

Before a headache or migraine begins, the blood vessels in the brain enlarge. Caffeine, by restricting blood flow, helps to reverse head pain.

Caffeine and caffeine-containing analgesics are effective for treating various types of primary and secondary headaches. 

Treating migraines with caffeine-containing pain relievers is considered safe and effective but shouldn’t be done more than twice a week, write the authors in Nutrients. In addition, caffeine isn’t the only option for migraines for patients who prefer to avoid it.

The Nutrients authors cite one study which found that 2 grams of magnesium sulfate was more effective at treating pain in migraine attacks than 60 mg of caffeine. Staying hydrated, getting enough sleep, and maintaining an otherwise healthy lifestyle are also essential for the prevention of severe headaches. Patients should be aware that although caffeine is a trigger for some headaches, it’s not the only possible contributor to headaches and headache relief alike.

 

Practical guidelines to consider

 

Based on what the research currently shows about connections between caffeine and headaches, patients should be mindful of their daily intake of caffeine from all sources. If patients want to cut back on caffeine, they should do so gradually to avoid withdrawal headaches. 

However, if patients prefer to keep consuming caffeine, it’s best to maintain consistent timing and intake throughout the week, even on the weekends or days off.

Ideally, caffeine intake should remain under 200 mg per day—that’s about two cups of coffee.