Restless Legs Syndrome in Black Adults: The Iron Link

Restless legs syndrome (RLS), also called Willis-Ekbom disease, is an irresistible urge to move the legs that strikes at rest, peaks in the evening and night, and eases the moment you walk or stretch. It is a real neurologic disorder, and for many people it traces back to low iron in the brain. Iron deficiency is more common in Black women than in white women, which makes this one of the more fixable causes of broken sleep, once someone names it.

There is no blood test or scan that diagnoses RLS. It is a clinical diagnosis built on four core criteria, all of which have to be present: an urge to move the legs, usually with an uncomfortable crawling, pulling, or aching sensation; symptoms that start or worsen during rest or inactivity; symptoms that are at least partly relieved by movement like walking or stretching; and symptoms that are worse in the evening or at night than during the day. A fifth check makes sure the pattern is not better explained by another condition such as leg cramps or positional discomfort.

RLS is common. A 2024 systematic review estimated global prevalence at 7.12% of adults, and it runs consistently higher in women (8.27%) than in men (5.98%). It also climbs with age and during pregnancy.

RLS gets confused with two things it is not. Nighttime leg cramps are sudden, painful, visible muscle knots, usually in the calf, that you can feel seize up. RLS is a deeper urge to move, not a cramp, and stretching relieves an RLS sensation only while you keep moving. Peripheral neuropathy, the nerve damage that often comes with diabetes, causes numbness, burning, or pins-and-needles that follow no clock and do not get better when you walk. RLS, by contrast, is tied to rest and the evening and eases with motion. If your symptoms are numbness or tingling that does not care what time it is, read our guide to numbness and tingling in the hands and feet instead, because that points toward neuropathy, not RLS.

Iron is the lever. The brain uses iron to make dopamine, and low brain iron is central to how RLS develops. You do not have to be anemic for this to matter. The threshold doctors act on is a ferritin (your iron storage marker) at or below 75 ng/mL, or a transferrin saturation under 20%. The international iron treatment guideline recommends starting oral iron in adults with RLS at that level, and using intravenous iron when ferritin sits between 75 and 100 ng/mL or when oral iron has not worked. Many people are told their iron is normal because it cleared the lab's anemia cutoff, while their ferritin sits well below the level that drives RLS.

This is where the Black-patient stakes come in. In NHANES data, iron deficiency affected 15.7% of non-Hispanic Black women of reproductive age versus 8.3% of non-Hispanic white women, close to a two-fold gap. Heavy menstrual bleeding, including from fibroids, drives a lot of that. If RLS and low iron travel together, and low iron is more common in Black women, then a simple ferritin test is one of the highest-value things you can ask for. Our piece on iron deficiency and anemia in Black women covers how to read your iron labs and what to do about them.

Iron is not the only driver. RLS is far more common in pregnancy, where prevalence can reach roughly a quarter to a third of women, often peaking in the third trimester, and where low ferritin and folate frequently play a role. It is also common in kidney disease, especially in people on dialysis. And several antidepressants can trigger or worsen it. A systematic review found mirtazapine and venlafaxine carry the highest risk of bringing on or aggravating RLS, while bupropion may actually reduce symptoms in the short term. Do not stop a prescribed antidepressant on your own. Tell the prescriber that your legs got restless after you started it, and ask whether a switch makes sense.

The first move is to fix what is fixable: replace iron if your ferritin is low, and clean up sleep habits and triggers. Cutting back on alcohol, nicotine, and late caffeine helps some people, and so does moving the legs with a walk or a stretch before bed. Replacing iron alone resolves or eases RLS for many people whose stores were low.

When medication is needed, the guidance has shifted hard. The 2025 American Academy of Sleep Medicine guideline now recommends gabapentin enacarbil, gabapentin, or pregabalin (a drug class called alpha-2-delta ligands) and recommends against the routine long-term use of dopamine drugs like pramipexole, ropinirole, and rotigotine. The reason is augmentation: over months to years on a dopamine agonist, RLS can get worse, start earlier in the day, and spread to the arms, the opposite of what the pill is supposed to do. If you are already on one of those medications and your symptoms are creeping earlier or getting more intense, that is a reason to call your prescriber, not to push the dose higher.

The prevalence data is genuinely mixed, and that mix tells a story. A community study in east Baltimore found RLS was just as common in Black adults (4.7%) as in white adults (3.8%) once it looked at people in their homes rather than in clinics. But a separate primary care study found Black patients carried a documented RLS diagnosis far less often than other patients, which the authors read as a sign of under-recognition rather than lower true disease. The honest read: RLS likely affects Black adults at similar rates, but gets named and treated less often. A symptom that gets brushed off as restlessness, anxiety, or just bad sleep is a symptom that never gets a ferritin test ordered.

You can start with a primary care clinician. Bring the four criteria with you, describe the evening-and-rest pattern, and ask for a ferritin level in addition to a standard blood count. If your iron is low, replacing it is often the whole treatment. If symptoms persist after your iron is corrected, ask for a referral to a neurologist or sleep specialist. To find a clinician who takes your symptoms seriously and understands the iron-deficiency picture, browse our directory of Black and Black-serving providers.