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Magnesium Glycinate

A well-absorbed, gentle-on-the-gut form of magnesium marketed for sleep and anxiety. The magnesium-for-sleep literature is small and low quality, and no trial has tested the glycinate form specifically against other forms.

Evidence last reviewed: August 2026

What the science says

  • Falling asleep faster Limited evidence

    A systematic review and meta-analysis pooled only three RCTs of oral magnesium in older adults with insomnia and found a reduction in time to fall asleep of roughly 17 minutes. The authors rated the certainty of the evidence as very low because the trials were small and at high risk of bias.

  • Anxiety and subjective sleep quality Limited evidence

    A systematic review of magnesium for self-reported anxiety and sleep quality found mostly small studies with inconsistent results, often using magnesium combined with other ingredients. No consistent effect emerged in people who are not magnesium deficient.

  • The glycinate form specifically Limited evidence

    Claims that glycinate is calmer or better absorbed than oxide or citrate rest on pharmacokinetic reasoning and a handful of comparative absorption studies, not on head-to-head sleep or anxiety trials. Its real practical advantage is causing less diarrhoea than magnesium oxide.

Dosage & safety

Studied doseTrials of oral magnesium for sleep used 320–500 mg elemental magnesium daily, taken in the evening. Check the label for elemental magnesium, not total compound weight — glycinate is heavy, so a 1000 mg capsule may supply only ~140 mg of magnesium.
SafetyGenerally well tolerated; loose stools are the main dose-limiting effect and are less common than with oxide or citrate. Magnesium reduces absorption of tetracycline and quinolone antibiotics, bisphosphonates and levothyroxine — separate by at least 2 hours. People with impaired kidney function should not supplement magnesium without medical supervision.

Scientific references

Where to buy

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