Rankings / Essentials — Vitamins & Minerals

Magnesium

Essentials · Mineral

Tier B+

Reviewed by Read Off Label · Last reviewed · How we grade

gabamineralnmda-modulatorotc
7.1 / 10
Tier B+
Ev 6 Bn 5 Sf 9

Bottom line

Read Off Label grades Magnesium as B+ (7.1/10) based on moderate evidence, moderate benefit magnitude, and a low-risk safety profile.

Form matters a lot.

Studied, labeled, or reported-use context: 200-400 mg elemental magnesium/day; glycinate for sleep, threonate for cognition, citrate/oxide for… — OTC; not individualized guidance.

If you were testing this on yourself

Two properties decide whether an n-of-1 experiment is readable and recoverable. These describe the experiment — they are not a judgment about whether to run it, and nothing here is a recommendation.

Can you undo it?

Reverses on stopping

Reversible. Excess is excreted renally in people with normal kidney function; the main dose-limiting effect, loose stools from the citrate and oxide forms, resolves within a day of stopping.

Can you tell if it worked?

Readable — GI effects same-day; sleep effects 1–2 weeks if present

Bowel tolerance is immediate and obvious. Sleep-onset latency if that is the goal. Serum magnesium is a poor readout — it is tightly regulated and stays normal despite low tissue stores.

What would fool you Most sleep self-experiments fail because sleep varies enormously night to night — you need several weeks of data either side, not a few nights. Serum levels looking "normal" tells you almost nothing about whether you were deficient.

What the evidence says

Form matters a lot. Oxide is cheapest but poorly absorbed and laxative. Glycinate is gentler and well-absorbed for general use. Threonate (MgT, Magtein) is marketed for brain penetration based on Slutsky 2010 preclinical data; real-world cognitive benefits modest. Fasting or minimal-food administration produces higher absorption.

Mechanism

NMDA receptor antagonism; GABA-A modulation; cofactor for 300+ enzymes; deficiency very common due to soil/diet; glycinate well-tolerated GI; threonate penetrates CSF better per Slutsky 2010

Studied, labeled, or reported dose & route

200-400 mg elemental magnesium/day; glycinate for sleep, threonate for cognition, citrate/oxide for constipation

This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.

Citations

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Common questions

What does the evidence show about Magnesium's effects?
Read Off Label rates the evidence for Magnesium as Moderate and the benefit magnitude as moderate, producing an overall grade of B+ (7.1/10). Form matters a lot.
What safety findings are reported for Magnesium?
Magnesium has a low risk profile in the database. Low (diarrhea dose-limiting with oxide/citrate; very rare hypermagnesemia in normal renal function) Legal status: OTC.
What doses or routes are reported for Magnesium?
200-400 mg elemental magnesium/day; glycinate for sleep, threonate for cognition, citrate/oxide for constipation This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
How does Magnesium work?
NMDA receptor antagonism; GABA-A modulation; cofactor for 300+ enzymes; deficiency very common due to soil/diet; glycinate well-tolerated GI; threonate penetrates CSF better per Slutsky 2010

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.