What supplements can help alleviate nocturnal (night-time) muscle cramps?

Nocturnal Muscle Cramps: Supplement Recommendations

For most adults with nocturnal leg cramps, magnesium supplementation provides minimal to no clinically meaningful benefit, and I recommend against routine use based on high-quality evidence. 1

Evidence Against Magnesium for Idiopathic Nocturnal Cramps

The strongest evidence comes from a 2020 Cochrane systematic review analyzing 11 randomized controlled trials with 735 participants. For older adults (mean age 61-69 years) with idiopathic nocturnal leg cramps:

• No significant reduction in cramp frequency: The difference was only -0.18 cramps per week compared to placebo (95% CI -0.84 to 0.49), with moderate-certainty evidence 1
• No meaningful percentage change: Only a 9.59% reduction from baseline versus placebo (95% CI -23.14% to 3.97%), which was not statistically significant 1
• No improvement in cramp intensity or duration: Participants rating cramps as moderate-to-severe showed no difference (RR 1.33,95% CI 0.81 to 2.21) 1
• No responder benefit: The percentage of people achieving ≥25% reduction in cramp frequency was identical between magnesium and placebo groups (RR 1.04,95% CI 0.84 to 1.29) 1

When Magnesium May Be Considered

Despite the overall negative evidence, one recent 2021 trial using magnesium oxide monohydrate (MOMH) 226 mg daily showed modest benefit:

• Slightly greater reduction in cramp episodes: -3.4 episodes versus -2.6 with placebo (p=0.01), though both groups improved significantly 2
• Improved sleep quality: Greater improvement compared to placebo (p<0.001) 2
• Reduced cramp duration: Statistically significant reduction (p<0.007) 2

However, this single positive study must be weighed against the comprehensive Cochrane review showing no benefit 1. An earlier 2002 trial of magnesium citrate 300 mg showed only a trend toward fewer cramps (p=0.07) that did not reach statistical significance 3

Side Effects to Counsel Patients About

• Gastrointestinal adverse events occur in 11-37% of magnesium users (versus 10-14% with placebo), primarily diarrhea 1
• Minor adverse events are more common: RR 1.51 (95% CI 0.98 to 2.33) compared to placebo 1
• Major adverse events and withdrawals are not significantly different from placebo 1

Recommended First-Line Approaches Instead

Non-Pharmacologic Interventions (Prioritize These)

• Stretching exercises: Recommended as first-line treatment, particularly calf stretching before bedtime 4, 5
• Adequate hydration before bedtime 4
• Avoid prolonged positioning of joints at end range during sleep 4

Medication Review

• Identify and modify cramp-inducing medications: Diuretics, calcium channel blockers, lithium, NSAIDs, intravenous iron sucrose, conjugated estrogens, raloxifene, naproxen, and teriparatide 4, 5

Rule Out Treatable Causes

• Check serum ferritin if restless legs syndrome is suspected: Values <50 ng/mL indicate iron deficiency requiring treatment 4
• Differentiate from restless legs syndrome by asking: "Does it vary over the day and is it worse in the evening?", "Is it relieved by movement?", "Does it come back after you sit or lie back down?" 4
• Consider trigger point injection for myofascial pain: Xylocaine injection at gastrocnemius trigger points showed equal efficacy to quinine during treatment and better prolonged effect at 4-week follow-up 6

Special Populations

Cirrhosis with Diuretic-Induced Cramps

For patients with cirrhosis experiencing muscle cramps from diuretics, baclofen is the recommended treatment:

• Start at 10 mg/day, increase weekly by 10 mg increments up to 30 mg/day 7, 4, 8
• Albumin infusion (20-40 g/week) can also relieve cramps 7, 4
• Correct electrolyte abnormalities, particularly hypokalemia and hypomagnesemia 7, 4

Pregnancy-Associated Cramps

The evidence for magnesium in pregnancy is conflicting and inconclusive—further research is needed before making firm recommendations 1

Critical Caveat About Magnesium Dosing

If magnesium is prescribed despite limited evidence:

• Use with extreme caution in renal insufficiency: Magnesium is renally excreted and can accumulate to toxic levels 8
• Typical doses studied: 300 mg elemental magnesium daily 3, 5, or magnesium oxide 226 mg daily 2
• Correcting documented hypomagnesemia (ferritin <45-50 ng/mL) is different from supplementation in normomagnesemic patients 8