C
supplementsleep
Magnesium Bisglycinate
Best evidence: C — Preliminary / mixed for Insomnia severity & sleep onset latency
A popular sleep supplement with only a thin, low-quality evidence base and a small effect that may not exceed placebo.
Graded outcomes
What the evidence says
C
Insomnia severity & sleep onset latency
Preliminary / mixed · Suggestive but unsettled — could go either way.
- Effect size
- Small (Cohen's d = 0.2) in the largest recent RCT; an earlier meta-analysis of 3 small trials found a ~17-minute reduction in sleep onset latency.
- Evidence base
- Thin evidence base — the meta-analysis pools only 3 RCTs (151 older adults); the largest single recent RCT is 155 adults.
- Population
- Effect may be concentrated in people with low baseline dietary magnesium intake (an exploratory subgroup finding, not confirmed). Systematic reviews describe the overall evidence quality as low and 'insufficient to recommend as a reliable treatment.'
- Dosage / protocol
- 250 mg elemental magnesium daily (as bisglycinate), used for 4 weeks in the most recent well-powered RCT.
- Contraindications & cautions
- Generally well-tolerated; use caution with kidney impairment or certain medications (some antibiotics, bisphosphonates) — consult a doctor.
Citations
- 1.PMC12412596 — RCT
- 2.BMC Complementary Medicine & Therapies (Springer) — Meta-analysis
- 3.The Better Sleep Clinic — evidence review
Compared with