Minerals2 min readLabel reading
Magnesium: which form for sleep, which for cramps?
Glycinate, citrate, oxide, malate, threonate. The differences are real, and the first one to check is not on the front of the bottle.
Compound weight is not mineral weight
Magnesium is always sold bound to something else, and the bound weight is what the front label likes to shout. Magnesium oxide is roughly 60% magnesium by weight; magnesium citrate is around 16%; magnesium glycinate sits near 14%. That is why one bottle can say 500 mg and another 1,000 mg and both deliver a similar amount of the mineral.
The supplement facts panel gives the figure, usually written as “Magnesium (as magnesium glycinate) 200 mg”. That 200 mg is the number to compare. Comparing front-label numbers instead just rewards whichever manufacturer picked the heaviest salt.
The forms, and what they are usually chosen for
No form is a sedative and none is a painkiller. What varies is solubility and how the gut handles it, which in practice decides whether a given dose is comfortable.
- Glycinate
- Bound to glycine. The usual pick for an evening dose, mostly because it is well tolerated at higher amounts.
- Citrate
- Well absorbed and mildly laxative, which is why it also turns up in constipation products. Fine for many people, a problem for some.
- Oxide
- Cheapest per milligram of magnesium and the least soluble. Common in low-cost bottles and in laxatives, for the same reason.
- Malate
- Bound to malic acid; often chosen for daytime dosing on tolerability alone.
- L-threonate
- The most expensive shelf, marketed for cognition. Treat the marketing carefully: the evidence base is thin and mostly preclinical.
Practical label reading
Check three lines and you have compared two products properly: elemental magnesium per serving, servings per container, and how many capsules make a serving. A 120-capsule bottle at three capsules a serving is a 40-day bottle, not a four-month one.
Loose stools are the ordinary signal that a dose or a form is too much, and splitting it across the day usually settles it. Anyone with reduced kidney function should not be self-dosing magnesium at all, because clearance is the whole issue. That one is a conversation with a doctor.
What the article names, on our shelves
Matched on the form printed in each product’s own title.
This is about labels, not about you: nothing here is a diagnosis or a dose. Reference intakes quoted are population figures. If you take medication, are pregnant or breastfeeding, or are asking because of a symptom, ask a pharmacist or a doctor first.
