Supplements with Magnesium: Every Form Explained and Who Needs What

Magnesium glycinate is the best all-around form for most people because it absorbs well, doesn't cause GI issues, and has a calming effect from the glycine. Take 300-400mg before bed. It helps with sleep, anxiety, muscle cramps, and general repletion. If you're only going to pick one form, this is it.

Magnesium citrate absorbs reasonably well and has a mild laxative effect. Good choice if constipation is part of your picture. 200-400mg daily. Don't take 400mg all at once unless you want to clear your schedule (and your colon).

Magnesium L-threonate (Magtein) crosses the blood-brain barrier more effectively than other forms. The research on cognitive function is early but interesting. 1,500-2,000mg of the threonate complex (which delivers about 144mg elemental magnesium). More expensive than other forms. Worth it if brain health is your main goal.

Magnesium taurate pairs magnesium with taurine, both of which support cardiovascular function. Some cardiologists specifically recommend this form for patients with heart rhythm concerns. 300-400mg daily.

Magnesium oxide is cheap and everywhere. It packs the most elemental magnesium per pill. But absorption is terrible (roughly 4%). You're basically making expensive stool. The one exception: if you just need a laxative, oxide works great for that.

Magnesium sulfate (Epsom salts) is for baths, not oral use. Soaking in it feels nice. There's minimal evidence that meaningful amounts absorb through skin.

Magnesium carbonate and hydroxide are mainly antacids (think Tums, Milk of Magnesia). Fine for heartburn. Not ideal for repletion.

One more thing: "magnesium complex" products that blend 3-4 forms often give you less of each than you'd want. Check the label for elemental magnesium per form. If they don't break it down, that's a red flag.

The RDA is 310-420mg daily depending on age and sex, but many researchers think optimal intake is closer to 400-600mg. Most people get 250-300mg from food, leaving a gap of 100-300mg to fill with supplements.

Timing matters. Magnesium glycinate and taurate work well before bed. Citrate is fine any time but keep it away from high-dose calcium (they compete for absorption). Threonate can be split morning and evening.

Don't take your entire dose at once. Split it into 2 doses if you're taking 400mg+. And if you get loose stools, you've hit your body's tolerance. Back off the dose slightly.