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This calculator provides general guidance only. Magnesium supplements can interact with medications and may not be safe for people with kidney disease. Always consult your healthcare provider.
Find your optimal magnesium dose and form based on your health goals
| Form | Absorption | Best For | Notes |
|---|---|---|---|
| Magnesium Citrate | High (25-30%) | General use, constipation | Good all-around choice, mild laxative |
| Magnesium Glycinate | High | Sleep, anxiety, muscle cramps | Calming, gentle on stomach, won't cause loose stools |
| Magnesium Oxide | Low (4%) | Migraines, constipation | High elemental content, but poor absorption |
| Magnesium L-Threonate | Moderate-High | Brain health, cognition, memory | Crosses blood-brain barrier, researched for cognitive benefits |
| Magnesium Malate | High | Energy, fibromyalgia, muscle pain | Malic acid supports ATP production |
| Magnesium Taurate | Good | Heart health, blood pressure | Taurine provides additional cardiovascular benefits |
| Magnesium Chloride | Good | Topical use, general supplementation | Available as oil/lotion for muscle cramps |
Note: About 50% of Americans don't get enough magnesium from diet alone. Soil depletion, processed foods, and certain medications contribute to widespread inadequacy.
| Food | Serving | Magnesium (mg) | % Daily Value |
|---|---|---|---|
| Pumpkin seeds | 1 oz (28g) | 156 mg | 37% |
| Chia seeds | 1 oz (28g) | 111 mg | 26% |
| Almonds | 1 oz (28g) | 80 mg | 19% |
| Spinach, cooked | ½ cup | 78 mg | 19% |
| Cashews | 1 oz (28g) | 74 mg | 18% |
| Black beans | ½ cup | 60 mg | 14% |
| Dark chocolate (70-85%) | 1 oz (28g) | 64 mg | 15% |
| Avocado | 1 medium | 58 mg | 14% |
Magnesium glycinate is bound to glycine (an amino acid) and is excellent for sleep, anxiety, and those with sensitive stomachs—it rarely causes loose stools. Magnesium citrate is bound to citric acid, absorbs well, and has a mild laxative effect, making it good for constipation but potentially problematic for those with loose stools.
For sleep or relaxation, take magnesium (especially glycinate) 30-60 minutes before bed. For energy support (malate), morning is better. For general supplementation, consistency matters more than timing. If you take multiple doses, spread them throughout the day.
Many forms of magnesium (especially oxide and citrate) draw water into the intestines through osmosis, causing loose stools. This is actually how magnesium-based laxatives work. To avoid this, use glycinate or malate forms, take with food, and stay under 350mg from supplements.
From food alone, it's nearly impossible to overdose as kidneys eliminate excess efficiently. From supplements, staying under 350mg/day avoids GI side effects for most adults. True toxicity (hypermagnesemia) is rare and usually only occurs with kidney disease or excessive IV/supplement doses.
For acute effects like constipation relief, you may notice results within hours. For sleep improvements, 1-2 weeks is typical. For migraine prevention or anxiety reduction, studies suggest 4-12 weeks of consistent supplementation may be needed to see significant benefits.
Magnesium L-threonate (Magtein®) is specifically researched for cognitive benefits because it crosses the blood-brain barrier better than other forms. If your primary goal is brain health, memory, or age-related cognitive decline, it may be worth the premium. For general supplementation, cheaper forms work fine.