Supplement analysis backed by scientific evidence · PT

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Moderate evidenceSleep & relaxation

Restless Legs Formulas

Iron plus magnesium blends sold for leg jitters at night. Iron genuinely helps when ferritin is low, which is the one situation where these formulas have a rationale; the magnesium and vitamin part rests on a handful of small trials.

Evidence last reviewed: August 2026

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What the science says

  • Iron repletion in iron-deficient RLS Moderate evidence

    A 2024 systematic review and meta-analysis of seven trials (539 participants) found that intravenous ferric carboxymaltose reduced IRLS symptom scores by about 5.8 points versus placebo, with the clearest benefit in confirmed iron deficiency. The American Academy of Sleep Medicine clinical practice guideline likewise supports iron repletion when ferritin is low, but the oral iron doses used in supplements are less well studied than the intravenous route.

  • Magnesium and vitamin B6 for symptoms Limited evidence

    A systematic review of 10 randomized trials (482 participants) reported that magnesium oxide and vitamin B6 improved sleep quality and RLS symptoms, while vitamin D showed no benefit. Half of the included studies were rated at high risk of bias, so the finding is preliminary.

  • Blends as sold have not been tested Limited evidence

    No randomized trial has tested a commercial multi-ingredient restless legs formula as a product. The evidence applies to single nutrients at defined doses, not to proprietary combinations.

Dosage & safety

Studied doseStudied oral iron doses are roughly 65 mg elemental iron daily (often with vitamin C) in people with ferritin below ~75 ng/mL; magnesium trials used 200–400 mg magnesium oxide at bedtime. Check ferritin before supplementing iron rather than taking it blindly.
SafetyDo not take iron long-term without a ferritin test: iron overload is a real risk, especially in haemochromatosis. Oral iron commonly causes constipation, dark stools and nausea; magnesium causes loose stools at higher doses. Iron interferes with absorption of levothyroxine, tetracyclines and quinolones. RLS that worsens or appears with antidepressants, antihistamines or dopamine agonist use needs a doctor, not a supplement.

Scientific references

Where to buy

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