Ann Jones used to have as many as two dozen migraines a month. To soothe her pain, the Arizona resident tried everything short of surgery, but nothing seemed to get rid of her chronic migraines. In 2018, her doctor mentioned a study being led by Dr. Mohab Ibrahim at the University of Arizona: Researchers were testing if daily exposure to green light could relieve migraines and other kinds of chronic pain.

After brushing aside initial skepticism, she enrolled in the study and started spending two hours each day in a dark room with only a white light, which served as the control. In the second half of the study, she swapped out the conventional light for a string of green LED lights. After about six weeks, Jones started going days in a row without migraines. Even when the headaches did come, they weren’t as intense as they had been before the green light therapy.

Some patients in the study of about 25 people noticed a change in just a few days. For others, it took several weeks. But overall, the migraine study’s principal investigator said that on average, people experienced a 60% decrease in the intensity of their migraines and a drop from 20 migraines a month to about six.

The results of the migraine study aren’t published yet. But they build on a small but growing body of research suggesting a link between green light and pain, including animal research done by Ibrahim’s team.

Apparently, previous research from Harvard found that green light is significantly less likely to exacerbate a migraine compared with other colors and, in some cases, can actually decrease the intensity of the headache. While we do not have robust data on humans yet, green light therapy could just help people with chronic migraines get rid of their pain without drugs.