Magnesium

There is biological plausibility and observational evidence that low magnesium is associated with obstructive sleep apnea (OSA), and magnesium can improve sleep in some contexts (insomnia, RLS, general sleep quality), but high-quality clinical trial evidence that magnesium treats OSA (i.e., reduces apnea–hypopnea index or fixes airway collapse) is limited to absent.

Magnesium has several physiological effects that could plausibly influence OSA or sleep-related breathing:

• Muscle relaxation & neuromuscular function. Magnesium is a natural calcium antagonist and modulates neuromuscular excitability. That could affect upper-airway dilator muscle tone (the same muscles that relax during obstructive events). ResMed Journal
• Anti-inflammatory and antioxidant effects. OSA causes intermittent hypoxia and systemic inflammation; magnesium is an antioxidant/anti-inflammatory nutrient, so repleting magnesium could reduce inflammation that may worsen airway reactivity. ResMed Journal
• Sleep architecture and neurotransmitter regulation. Magnesium influences GABA and melatonin pathways; supplementation has been shown to improve sleep latency and subjective sleep quality in some insomnia studies (relevant because better sleep and less fragmented sleep can reduce symptoms and comorbidities). SpringerLink

Important: These mechanisms are plausible, but plausible ≠ proven for treating OSA. The mechanism-based case is supportive but does not replace randomized clinical trials showing improvement in apnea severity. ResMed Journal

These are common, evidence-informed practices used in clinical and consumer guidance — treat as general guidance, not a prescription.

Forms to prefer (better absorbed or better tolerated for sleep):

• Magnesium glycinate (bisglycinate) — often recommended for sleep because it’s well absorbed and less likely to cause diarrhea. Office of Dietary Supplements
• Magnesium citrate — well absorbed but more likely to cause looser stools (sometimes used for constipation at higher doses). Office of Dietary Supplements

Typical dosing used in sleep/sleep-quality trials and expert advice:

• Start low, commonly 200–400 mg elemental magnesium once daily, usually taken ~30–60 minutes before bed. Many practitioners advise starting ~200 mg and titrating as needed up to ~300–400 mg if tolerated. (Elemental magnesium vs supplement salt: check product label.) Rise Science
• Upper limits: Official US guidance traditionally set the tolerable upper intake level (UL) for magnesium from supplements at 350 mg/day (this UL excludes magnesium from food). Some trade groups have recently proposed higher safe supplement levels (e.g., CRN guidance suggesting up to 500 mg/day for healthy adults), but that is not yet an official federal guideline — so caution is warranted. (See Warnings below.) Office of Dietary Supplements

How to try it practically (example plan frequently used by clinicians):

1. Check baseline: discuss with your clinician and, if indicated, check kidney function (serum creatinine/eGFR) and current medications. Office of Dietary Supplements
2. Select form: choose glycinate or citrate (glycinate if you have sensitive gut). Office of Dietary Supplements
3. Start dose: begin 200 mg elemental at night for 1–2 weeks. If tolerated and no improvement, increase to 300–400 mg as needed (and as advised by your clinician). Rise Science
4. Duration to assess: some sleep studies show subjective sleep changes within 1–4 weeks; allow several weeks to judge effect on sleep quality. But do not expect magnesium to replace CPAP or other established OSA therapies without objective improvement measured by sleep testing. SpringerLink

Practical note: product labels list the amount of elemental magnesium — e.g., “Mg glycinate 300 mg” may or may not mean 300 mg elemental Mg (manufacturers vary). Prefer third-party tested supplements.

(See NIH consumer & professional fact sheets for dosing forms and interactions.) Office of Dietary Supplements

Systematic review — serum magnesium in OSA (MDPI paper): reviews studies measuring serum Mg in OSA patients vs controls; some studies show lower Mg in OSA and links with oxidative stress markers. This is evidence of association and a potential mechanistic link. MDPI

Review: “Magnesium is a key trace element in obstructive sleep apnea: evidence …” (2025 review) — a recent narrative/review article that summarizes anti-inflammatory, antioxidant and muscle-relaxant rationale and calls for more interventional trials. (Usefulness: mechanism and argument for trials, but not definitive clinical proof.) ResMed Journal

Systematic review of magnesium and sleep quality (Springer, 2022) — shows associations between magnesium status and sleep quality (subjective measures), but randomized trials were heterogeneous and results uncertain for sleep disorders overall. This supports that magnesium can improve subjective sleep in some people, though not specifically OSA outcomes. SpringerLink

Randomized trials for insomnia / general sleep — small RCTs and pilot trials (e.g., older-adult insomnia trials, small crossover trials) found improvements in subjective sleep quality with magnesium in some cohorts — useful for sleep quality but not evidence of reducing apneas. Example: a randomized crossover study of magnesium in adults with nonclinical insomnia symptoms (small N) reported improvements in sleep outcomes. Sciety