What is the recommended dose of magnesium glycinate for treating muscle cramping and restless legs at night?

Magnesium Glycinate for Nighttime Muscle Cramping and Restless Legs

Magnesium supplementation is not recommended as a treatment for either muscle cramping or restless legs syndrome, as high-quality evidence demonstrates it is ineffective for both conditions. 1, 2, 3, 4

Evidence Against Magnesium for These Conditions

For Muscle Cramps

• A Cochrane systematic review of 11 randomized controlled trials (735 participants) found that magnesium supplementation provides no clinically meaningful benefit for skeletal muscle cramps in older adults, with differences in cramp frequency being small, not statistically significant, and showing minimal heterogeneity (I² = 0% to 12%). 3
• The percentage of individuals experiencing a 25% or better reduction in cramp rate was no different between magnesium and placebo (RR 1.04,95% CI 0.84 to 1.29). 3
• Cramp intensity and duration measures showed no statistically significant differences at four weeks. 3

For Restless Legs Syndrome

• The American Academy of Sleep Medicine 2025 guidelines do not include magnesium as a recommended treatment for RLS, instead prioritizing an evidence-based algorithm starting with iron status assessment followed by alpha-2-delta ligands. 1, 2
• A systematic review specifically examining magnesium for RLS/PLMD found only one randomized placebo-controlled trial, which did not find a significant treatment effect and may have been underpowered, concluding that "it is not clear whether magnesium helps relieve RLS or PLMD." 4
• While one small 2022 study (75 patients) suggested benefit from 250 mg magnesium oxide daily, this single study is insufficient to override the lack of inclusion in evidence-based guidelines and the negative systematic review. 5

What Actually Works: Evidence-Based Alternatives

For Restless Legs Syndrome

• The American Academy of Sleep Medicine strongly recommends alpha-2-delta ligands (gabapentin, gabapentin enacarbil, or pregabalin) as first-line therapy with moderate certainty of evidence. 1, 2
• Check serum ferritin and transferrin saturation in all RLS patients; supplement with oral ferrous sulfate if ferritin ≤75 ng/mL or transferrin saturation <20%. 2
• IV ferric carboxymaltose is strongly recommended for patients with appropriate iron parameters who don't respond to oral therapy. 2

For Muscle Cramps

• The American College of Physicians recommends alpha-2-delta ligands (gabapentin, gabapentin enacarbil, or pregabalin) as first-line treatment for leg muscle spasms due to their efficacy and lower risk of adverse effects. 6

Critical Pitfalls to Avoid

• Do not use magnesium as monotherapy for clinically significant RLS without first addressing iron status and considering guideline-recommended treatments. 2
• Do not confuse nocturnal leg cramps with RLS—RLS has specific diagnostic criteria requiring an urge to move with relief by movement, symptoms beginning or worsening during rest, and symptoms worse in evening/night. 1, 7
• Avoid dopamine agonists (pramipexole, ropinirole, rotigotine) for RLS despite their historical use, as augmentation—a paradoxical worsening of symptoms—occurs in the majority of long-term users. 1, 2

If You Still Choose to Try Magnesium

• The FDA-approved dosing for magnesium glycinate is one tablet daily, preferably with a meal. 8
• Be aware that 11-37% of participants in clinical trials experienced gastrointestinal adverse events (primarily diarrhea) with oral magnesium supplementation. 3
• This approach lacks evidence-based support and delays implementation of proven effective treatments. 1, 2, 3, 4