Health
Magnesium Dosage by Body Weight Calculator
Suggested magnesium intake based on weight, age, and sex.
In this article
Magnesium RDA
Adult males need 400–420mg/day; females 310–320mg/day. The average American diet provides ~250mg/day — leaving most people with a 100–170mg deficit. Magnesium is involved in 300+ enzymatic reactions, including sleep regulation, muscle function, and blood sugar control.
Best supplement forms
- Glycinate: Best for sleep/anxiety, gentle on stomach
- Citrate: Good absorption, mild laxative effect
- L-Threonate: Crosses blood-brain barrier — best for cognitive benefits
- Oxide: Cheap but only ~30% absorbed
⚡ CalcWolf Insight
Approximately 50% of Americans do not meet the recommended daily intake of magnesium from their diet alone.
Frequently asked questions
How much magnesium should I take?▾
Most adults benefit from 200–400mg elemental magnesium/day supplementally. Start low (100–200mg) to assess tolerance. Magnesium is water-soluble — excess is excreted.
What form of magnesium is best?▾
Magnesium glycinate for sleep and anxiety (best absorbed, least GI side effects). Magnesium citrate for constipation relief. Magnesium L-threonate for cognitive function. Magnesium oxide is cheap but poorly absorbed (4% bioavailability). Avoid magnesium oxide if you want systemic benefits.
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