AASM Recommendations on Vitamin D for Restless Legs Syndrome
The 2025 AASM clinical practice guideline does not include any recommendations regarding vitamin D supplementation for the treatment of RLS in the general adult population. 1
What the AASM Guidelines Actually Recommend
The AASM guideline is notably silent on vitamin D, focusing instead on:
- Iron supplementation as the primary micronutrient intervention, recommended when ferritin ≤75 ng/mL or transferrin saturation <20% 2
- Alpha-2-delta ligands (gabapentin, gabapentin enacarbil, or pregabalin) as first-line pharmacological treatment 2
- IV iron formulations (ferric carboxymaltose, iron sucrose) for appropriate candidates 2
Special Population Exception: End-Stage Renal Disease
The only vitamin mentioned in the AASM guideline is vitamin C, not vitamin D:
- For adults with RLS and end-stage renal disease (ESRD), the AASM suggests using vitamin C supplementation (conditional recommendation, low certainty of evidence) 1
- This recommendation is specific to dialysis patients and does not extend to the general RLS population 3
The Research Evidence on Vitamin D (Not in Guidelines)
While the AASM does not recommend vitamin D, research studies suggest potential benefit:
- Vitamin D deficiency appears common in RLS patients, with some studies showing 60% prevalence of deficiency 4
- Small prospective studies demonstrated improvement in International Restless Legs Severity Scale (IRLSS) scores after vitamin D supplementation in deficient patients (from 24.9 to 21.1 points, p <0.001) 4
- Another small study showed median RLS severity scores improved from 26 to 10 after vitamin D correction (p = 0.002) 5
- Vitamin D levels correlate negatively with poor sleep quality in RLS patients 6
Clinical Approach Based on Current Evidence
Given the absence of guideline recommendations, a pragmatic approach would be:
- Do not routinely check or supplement vitamin D as part of standard RLS management, as it lacks guideline support 1
- Prioritize iron status assessment first, as this has strong guideline backing 2
- If checking vitamin D levels, consider supplementation only if deficiency is documented (<50 nmol/L or <20 ng/mL), recognizing this is based on limited research evidence rather than guideline recommendations 4, 5
- The evidence for vitamin D remains insufficient for the AASM to make any formal recommendation, positive or negative 1
Critical Pitfall to Avoid
Do not substitute vitamin D supplementation for guideline-recommended treatments. The research on vitamin D involves small, uncontrolled studies with significant methodological limitations 7, 8. The AASM's silence on vitamin D in their comprehensive 2025 guideline suggests the evidence was evaluated and found insufficient to warrant a recommendation 1.