Glossary
Magnesium
Updated February 28, 2026
Magnesium supports neuromuscular, energy, and recovery systems through multiple cellular roles. RDA is 400–420 mg for males and 310–320 mg for females, with athletes often requiring the upper end due to sweat and training losses.
Mechanism clusters
| Cluster | Core role | Practical signal |
|---|
| Nerve and muscle | Regulates calcium channel gating for contraction | Reduced cramp frequency and calmer contraction quality |
| Energy metabolism | Required cofactor for ATP production in over 300 enzymes | Improved work capacity when previously depleted |
| Sleep context | GABA receptor modulation and nervous system downshift | Less fragmented night recovery when dose timing is consistent |
Supplement forms
| Form | Bioavailability | Best use case |
|---|
| Magnesium glycinate | High (~80% absorption) | Sleep support and general repletion |
| Magnesium citrate | Moderate to high | General use and mild constipation relief |
| Magnesium L-threonate | Crosses blood-brain barrier | Cognitive support and focus |
| Magnesium oxide | Low (~4% absorption) | Poor choice for repletion despite high elemental mg |
Food-first source hierarchy
| Source tier | Examples | Mg per serving | Use rule |
|---|
| Tier 1 | Pumpkin seeds, spinach, black beans | 156 mg/oz seeds, 157 mg/cup cooked spinach | Use as baseline intake |
| Tier 2 | Whole grains, dark chocolate, edamame | 60–80 mg per serving | Add when intake gaps exist |
| Tier 3 | Supplement support | Varies by form and dose | Use only when food-first options cannot close gap |
Timing strategy for training and sleep
| Timing block | Strategy |
|---|
| Training week | Place around higher sweating blocks if intake feels unstable |
| Evening routine | Take glycinate 30–60 minutes before bed for sleep benefit |
| Recovery focus | Pair with food logging and hydration |
Prolonged high-dose caution
| Red flag | Action |
|---|
| Stool softening and repeated loose stool | Lower dose and review all magnesium-rich products |
| Marked fatigue or dizziness | Pause additions and seek medical review if persistent |
| Sleep or digestion worsen over several days | Revert toward food-first and test one variable at a time |
Magnesium works best alongside potassium and proper electrolyte balance. Focus on getting these minerals from whole foods before considering supplements.