Iron Supplements to Treat Restless Legs Syndrome

Reviewed by: HU Medical Review Board | Last reviewed: March 2023

Doctors have known since the 1950s that taking iron can help people with restless legs syndrome, even if the person does not have anemia. That is because many people with restless legs syndrome (RLS) have low iron levels in the brain while iron blood levels can appear normal.1,2

While you can buy iron over-the-counter, it should not be taken without a doctor’s supervision. That is because iron supplements can cause many side effects, including some that are serious.

How does iron work to improve RLS?

Iron supplements increase iron levels in the brain. This helps the parts of the brain that control movement work better.

Iron is most often taken by mouth. It may take up to 3 months for RLS symptoms to improve. And, iron treatment may need to be repeated every 3 to 6 months. Some people find that they can stop taking other drugs for RLS if their iron levels improve.1,2

Rarely, people with severe RLS and anemia may need intravenous (IV) iron if they do not respond to taking iron pills. These IVs are given during a number of office or hospital visits over the course of up to 12 weeks. It often takes weeks to relieve RLS symptoms.3

What are the possible side effects of iron supplements?

Taking iron can be hard on the body. Iron supplements can cause an upset stomach, constipation, and other side effects. Some people may need to take iron pills every other day or even less often. Not everyone can take iron. Eating more red meat, liver, spinach, and other foods high in iron may help too.1

These are not all the possible side effects of iron supplements. Talk to your doctor about what to expect when taking iron supplements. You also should call your doctor if you have any changes that concern you when taking iron supplements.

Things to know about iron supplements

Taking iron on an empty stomach with orange juice or a Vitamin C pill will help the body absorb the iron better. You should not take iron with calcium supplements, antacids, or dairy products such as milk. These can decrease the amount of iron that is absorbed. Taking iron at night may help the brain absorb iron better.1,2

Your doctor will need to monitor your blood work during this time to avoid the serious complication of iron overload.2

There are many different types of iron available over-the-counter (OTC). Talk to your doctor about which type and what dose is right for you.

Before beginning treatment for RLS, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

Other treatment options for RLS

Restless legs syndrome may also be treated with:

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