Magnesium Glycinate Dosage Calculator
Doses above are elemental magnesium, not the total weight of the compound on a supplement label — magnesium glycinate is only about 14% elemental magnesium by weight, so "1,000 mg magnesium glycinate" is roughly 140 mg of actual elemental magnesium. The RDA (310–420 mg depending on age and sex) covers total intake from food and supplements combined, per NIH Office of Dietary Supplements guidance. The 350 mg figure is the tolerable upper intake level for supplements alone (not counting food) — going meaningfully above it raises the risk of diarrhea and GI upset. This is general nutrition information, not medical advice — check with a doctor before starting a new supplement, especially if you take other medications or have kidney issues.
Free magnesium glycinate dosage calculator using NIH Office of Dietary Supplements RDA and UL figures — see your age/sex RDA, a goal-based elemental magnesium target, and the equivalent glycinate compound dose. No affiliate product links.
How it works
- Pick your age group, sex, and goal (sleep, stress, or muscle recovery)
- See your daily RDA for total elemental magnesium (food + supplements combined) from NIH ODS
- See a goal-based elemental magnesium supplement target and its equivalent magnesium glycinate compound dose, with a warning if it approaches the supplement upper limit
Frequently asked questions
Why does the calculator use "elemental magnesium" instead of the mg number on my supplement bottle?
Supplement labels usually list the total compound weight, not the actual magnesium content. Magnesium glycinate is only about 14% elemental magnesium by weight — a 1,000 mg magnesium glycinate capsule contains roughly 140 mg of actual elemental magnesium. NIH's RDA and upper-limit figures are defined in elemental magnesium, so that's what this calculator uses first, then converts to a compound dose.
How much magnesium glycinate should I take for sleep?
Most consumer guides suggest 200–400 mg of elemental magnesium taken 30–60 minutes before bed — this calculator caps that range at 350 mg to stay within the NIH-listed supplement upper limit.
Is more magnesium always better?
No. The NIH Office of Dietary Supplements lists 350 mg/day of elemental magnesium from supplements alone (not counting food) as the tolerable upper intake level for adults — going meaningfully above that raises the risk of diarrhea and gastrointestinal upset without added benefit.
Why isn't this based on my body weight?
NIH's magnesium RDA is set by age and sex, not body weight — unlike creatine, there's no widely-established per-kilogram dosing formula for magnesium in the research this calculator draws from, so a bodyweight-based number would be invented rather than evidence-based.
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2026-09-22Update history
- 2026-09-22 Launched: magnesium glycinate dosage calculator with NIH ODS-sourced RDA by age/sex, goal-based elemental magnesium targets (sleep/stress/recovery), glycinate compound-dose conversion, and an upper-limit warning. Entirely client-side, no affiliate supplement links.