Although no large studies have been conducted, smaller studies suggest a possible role of supplements in reducing the symptoms of restless legs syndrome (RLS), a condition that causes uncomfortable "creepy-crawly" sensations, agitation, and the need to move the legs when trying to fall asleep. Women are twice as likely to suffer from restless legs syndrome than men, and it occurs more often with increasing age (Wang, Sleep Med 2009).
People with deficient or low blood levels of iron are also more likely to experience RLS. As discussed in more detail in the "What It Does" section of the Iron Supplements Review, a study found that taking a combination of high-dose iron and vitamin C (which helps to increase iron absorption) can decrease symptom severity in people whose blood levels of iron are low. However, it's important to consult your physician before supplementing with iron for RLS.
As discussed in the "What It Does" section of the Magnesium Supplements Review, a preliminary study suggested that taking magnesium in the evening could be helpful for RLS; however, there have not been large, well-controlled studies investigating this treatment.
Similarly, as discussed in the "What It Does" section of the Potassium Supplements Review, one preliminary study suggested that potassium may help reduce the severity of RLS symptoms, but no well-controlled studies have been conducted to prove this.
Be aware that melatonin supplements may increase leg movements in people with restless legs syndrome RLS. Caffeine, alcohol, SSRI antidepressants, antihistamines, and most antipsychotic and antinausea medications can potentially increase RLS symptoms (Cotter, Ther Clin Risk Manag 2006).
GABA (gamma-aminobutyric acid) is a natural "inhibitory neurotransmitter," meaning it blocks impulses between the nerve cells, resulting in a calming effect. Although drugs that affect GABA activity in the brain, such as (gabapentin (Neurontin), alprazolam (Xanax), diazepam (Valium), are sometimes prescribed to reduce the severity of RLS symptoms, taking GABA as a supplement does not significantly increase GABA levels in the brain and there do not appear to be any studies investigating the effects of GABA supplementation on symptoms in people with restless legs syndrome, although there is some evidence GABA supplementation may have modest benefit in people with insomnia.
Also be aware that RLS can occur as a result of kidney or liver disease. People with these conditions should consult with a healthcare professional before taking supplements (Cotter, Ther Clin Risk Manag 2006; Franco, J Clin Sleep Med 2008).