Magnesium Glycinate for Sleep: Evidence, Dosing, and Safety

Magnesium glycinate (bisglycinate) chelates magnesium to glycine—an inhibitory neurotransmitter. This form has high bioavailability and minimal laxative effect vs. oxide/citrate.

Why Magnesium for Sleep?

• Regulates NMDA (glutamate) and GABA receptors → nervous system calming.
• Low Mg²⁺ linked to insomnia, restless legs, poor sleep efficiency.
• Glycine independently lowers core temperature and improves sleep onset/quality.

Clinical Evidence

• RCT: 500 mg/day Mg-glycinate × 8 weeks → significant improvement in insomnia severity (ISI) and sleep efficiency in older adults.
• RCT: 200 mg/day × 4 weeks → reduced sleep latency, improved subjective quality in anxious adults.
• Meta-analyses: Magnesium supplementation modestly improves sleep parameters, especially in deficient/older populations.

Dosing and Use

• 200–400 mg elemental magnesium (≈1–2 g glycinate) 30–60 min before bed.
• Start low; split dose if GI sensitivity.
• Combine with glycine (3 g) for synergy.

Safety

• Generally well-tolerated.
• Side effects: loose stool (rare with glycinate), nausea.
• Caution: renal impairment (dose adjust), myasthenia gravis.
• Interactions: bisphosphonates, antibiotics (tetracyclines, quinolones)—space 2h.

Magnesium glycinate is a rational, low-risk sleep support—especially if dietary intake is low (common). Test RBC magnesium if unsure.