Iron for treating restless legs syndrome Original paper

Iron status is known to play a role in restless legs syndrome (RLS). In recent years, more randomized controlled trials have been published examining the optimal iron dosages and delivery methods (oral or via IV) for people with RLS.

This was a meta-analysis of 10 randomized controlled trials with 455 participants (72% female). The primary outcome was change in RLS symptoms. For the oral studies, participants took 325 mg of iron sulfate twice a day. For the IV studies, participants took a 1,000 mg dose of iron either all at once or split across weeks. Ferric carboxymaltose was the most common form of IV iron used in the studies.

Iron supplementation, either via IV or orally, significantly improved symptoms of RLS. However, there were only two studies that investigated oral iron supplementation, so confidence in the effect of this method is less certain. Participants experienced some mild stomach upset during both treatment options. The study also suggested that people with an iron deficiency may experience greater symptom improvements after supplementation, based on very limited evidence, although the improvement didn’t reach statistical significance.