Restless Legs and Iron: Ferritin Targets and Supplements That Work

When your legs feel like they’re crawling with ants at night - even when you’re perfectly still - it’s not just restlessness. It’s restless legs syndrome (RLS), a neurological condition that disrupts sleep for millions. And for many, the root cause isn’t stress or caffeine. It’s iron. Not in your blood, but in your brain.

Why Iron Matters More Than You Think

RLS isn’t just a nuisance. It’s a signal. And that signal is often low iron in the brain’s movement centers, especially the substantia nigra. Even if your blood tests look normal, your brain might be starving for iron. This isn’t about anemia. It’s about functional deficiency. Your body might have enough iron circulating, but it can’t get it where it’s needed.

That’s why ferritin - the protein that stores iron - is the key marker. The American Academy of Sleep Medicine and the American Academy of Neurology agree: if your ferritin is below 50 ng/mL, you’re in the range where iron therapy can make a real difference. And it’s not a guess. Studies show that people with ferritin under 50 have a 50% or better chance of seeing major symptom improvement with iron supplements.

Think about it: if you’ve been taking dopamine drugs like pramipexole for years and your symptoms keep getting worse, it might not be the disease progressing. It might be augmentation - a side effect where the medication makes RLS worse over time. Up to 70% of long-term users develop it. Iron therapy doesn’t cause that.

What Ferritin Level Should You Aim For?

Most labs say ferritin between 12 and 300 ng/mL is “normal.” But that’s not good enough for RLS.

• Below 50 ng/mL: Clear signal to start iron therapy. Around half of patients see significant relief.
• 50-75 ng/mL: Still worth trying. About one in three people improve, even if they’re technically in the “normal” range.
• 75-100 ng/mL: Target zone for best results. Once you hit this, symptoms often stabilize or disappear.

One 2021 study found that patients who reached ferritin levels above 75 ng/mL had symptom control lasting up to two years after just one IV iron treatment. That’s not a fluke. That’s a pattern.

And here’s something surprising: some people with RLS have normal ferritin but high hepcidin - the hormone that blocks iron from entering cells. High hepcidin means your body is locking iron away, even if you’re eating enough. That’s why just eating more red meat won’t fix it. You need targeted therapy.

Oral Iron: How to Take It Right

If your ferritin is under 50, your doctor should recommend oral iron. But not just any iron. Ferrous sulfate is the gold standard: 325 mg tablets give you 65 mg of elemental iron.

Here’s how to make it work:

1. Take it on an empty stomach. Iron absorbs best without food. If you can’t handle that, take it one hour before or two hours after meals.
2. Pair it with vitamin C. A 100-200 mg vitamin C tablet or a glass of orange juice boosts absorption by up to 30%.
3. Avoid calcium, antacids, and coffee. These block iron absorption. Wait at least two hours after taking iron before having dairy, Tums, or coffee.
4. Try alternate-day dosing. Taking iron every other day improves tolerance. Studies show you get nearly the same ferritin rise with fewer stomach issues.

Side effects? About 28% of people get nausea, constipation, or dark stools. That’s common. But it’s not a reason to quit. Many switch to ferrous gluconate or iron bisglycinate - gentler on the gut - and still get results.

When Oral Iron Isn’t Enough

Some people just can’t absorb enough iron through the gut. That’s especially true if you’ve had gastric bypass surgery, have celiac disease, or have chronic inflammation. If you’ve taken 3-6 months of oral iron and ferritin is still under 30 ng/mL, it’s time to talk about IV iron.

IV ferric carboxymaltose - a single 1,000 mg infusion - can boost ferritin by over 120 ng/mL in just six weeks. In one trial, 68% of RLS patients had major symptom relief after one infusion. And unlike pills, it doesn’t upset your stomach.

It’s not expensive either. A single IV dose costs about $500-$800. Compare that to $2,400-$4,800 a year for pramipexole or ropinirole. And IV iron doesn’t cause augmentation. Ever.

What About Diet?

You might think eating more red meat will fix RLS. It helps - but not enough.

A 3-ounce serving of beef liver gives you about 5 mg of heme iron. That’s the best-absorbed form. But you’d need to eat nearly 13 servings a day to match the 65 mg in one ferrous sulfate tablet. And even then, absorption varies.

Plant-based iron (non-heme) from spinach or lentils is poorly absorbed - especially if you’re drinking tea or coffee with meals. So while a balanced diet supports overall health, it won’t raise ferritin fast enough to treat RLS.

How Long Until You Feel Better?

Don’t expect overnight results. Iron therapy is slow. Most people notice small improvements after 2-4 weeks. Full effect takes 8-12 weeks. That’s why so many give up too soon.

Track your symptoms. Use the International Restless Legs Scale (IRLS). Rate your symptoms from 0-40 before and after treatment. A drop of 10 points or more is considered a good response. In one study, IV iron cut IRLS scores from 28.5 to 14.3 on average. That’s the difference between losing sleep every night and sleeping through the night.

What to Do Next

If you have RLS and haven’t had your ferritin checked, ask your doctor. Don’t wait for your symptoms to get worse. Don’t assume your “normal” lab results mean you’re fine. Ferritin under 50 ng/mL is a medical red flag for RLS.

Here’s your action plan:

1. Get a blood test: ferritin, serum iron, TIBC, transferrin saturation.
2. If ferritin ≤ 75 ng/mL, start iron therapy.
3. Take 65 mg elemental iron daily with vitamin C, on an empty stomach.
4. Re-test ferritin after 8-12 weeks.
5. If no improvement or intolerable side effects, ask about IV iron.
6. Don’t start dopamine drugs unless ferritin is above 100 ng/mL and symptoms persist.

RLS doesn’t have to be a lifelong battle with pills that make things worse. For a huge portion of sufferers, the solution is simple: fix the iron. And it works.

What About Other Supplements?

Magnesium? Folate? Vitamin D? Some people swear by them. But there’s no strong evidence they fix RLS on their own. They might help if you’re deficient - but they won’t replace iron if your ferritin is low.

Stick to the science. Iron is the only supplement with consistent, replicated results in RLS. Everything else is a side note.

Long-Term Outlook

Iron therapy isn’t a cure - but it’s the closest thing we have. Once your ferritin hits 75-100 ng/mL, many people stay symptom-free for months or years. Some need occasional top-ups. Others never need another dose.

And the future? New iron formulations like liposomal iron and ferric maltol are in trials. They’re designed to absorb better and cause fewer side effects. In early studies, they cut stomach problems by 60% and doubled absorption rates.

For now, the message is clear: if you have restless legs, get your ferritin tested. If it’s low, treat it. Not with guesswork. Not with herbs. With real, proven iron therapy.