And the new study is far from definitive proof. “Our findings need to be confirmed by more studies with a larger number of patients,” says Dr. Wepner, who is currently wrapping up a similar study in 100 fibromyalgia patients.

Doubts about vitamin D’s ability to ease chronic pain remain. “This is somewhat supportive evidence, that vitamin D may be helpful, but it doesn’t necessarily prove it,” says Jeffrey M. Thompson, MD, associate professor of physical medicine and rehabilitation at Mayo Clinic in Rochester, Minn., and former director of Mayo’s fibromyalgia treatment program.

About the study, he says, “I think the numbers are low, only 30 study subjects, so that’s an issue.”  And the results “didn’t really find much in the way of statistically significant changes. They found a pain score reduction of 20 percent, which is trending in the right direction, but in general, a pain score decrease of more than 30 percent would be considered clinically significant.” (“Clinically significant” means something is important in a real-world setting – to a patient or doctor, for example.)   

In his own practice, Dr. Thompson says, “I haven’t found it to be very helpful in general; it hasn’t been dramatic. That’s basically what this is showing.”

For some people, taking vitamin D supplements may be a good idea regardless of whether they help with pain. “If people are low in vitamin D, certainly replacing vitamin D and probably even getting them up to the high ranges of normal vitamin D makes sense for general bone and muscle health. But it’s not likely that it’s going to be a dramatic change in pain…” says Dr. Thompson.

Even if vitamin D helps take the edge off pain, it won’t replace other medications used to treat fibromyalgia, says Dr. Wepner. “This cannot cure the complex of symptoms completely but may help to reduce the pain,” he says. “Vitamin D supplementation is a cheap and relatively safe option if the serum calcifediol level is controlled regularly. But it still is important that [fibromyalgia] patients should also be treated [according] to international guidelines including a multimodal therapy approach.”