Magnesium bisglycinate, magnesium citrate, and magnesium oxide are the same essential mineral in three different packages: bisglycinate is the gentle, well-absorbed form most people choose for nighttime use*, citrate is a well-absorbed everyday form with a mild laxative effect at higher amounts, and oxide carries the most elemental magnesium per tablet but is absorbed poorly. Each form has a legitimate job — the label just needs to match it.
Magnesium bisglycinate is magnesium bound to two glycine molecules, and pure magnesium bisglycinate contains 14.1% elemental magnesium by weight. The chelate is stable through digestion, absorbs well, and is gentle on the stomach — the reason it is the form most often taken at night.* TAO Daily’s Sleep & Calm contains 200 mg of elemental magnesium from fully reacted magnesium bisglycinate per two-capsule serving.
Magnesium citrate binds magnesium to citric acid and contains roughly 16% elemental magnesium by weight. It absorbs well and suits everyday use; at higher amounts it draws water into the digestive tract — a mild laxative effect that some people want and others avoid. That is a property, not a flaw: it belongs on the label so you can match the form to your goal.
Magnesium oxide is the most compact form — roughly 60% elemental magnesium by weight — which is how a single small tablet can list 400 or 500 mg. The trade-off is absorption: studies measure its uptake well below the chelated and citrate forms, so a larger share passes through unabsorbed. It is inexpensive and useful where elemental density matters more than absorption.
| Form | Elemental Mg | Absorption | Typical use | Gentleness |
|---|---|---|---|---|
| Bisglycinate, fully reacted | ≥14.0% (specified) | Well absorbed | Nightly routines, sensitive stomachs | Very gentle |
| Citrate | ~16% | Well absorbed | Everyday use; mild laxative effect at higher amounts | Moderate |
| Oxide | ~60% | Low | High-elemental tablets at low cost | Can loosen stools |
Elemental percentages are properties of the compounds; absorption comparisons reflect published pharmacokinetic studies. Forms, not brands.
How to read a label: “fully reacted” means every milligram of bisglycinate is truly chelated, not blended with cheaper oxide. Pure magnesium bisglycinate contains 14.1% elemental magnesium by weight; ours is specified at ≥14.0% elemental magnesium — an elemental percentage well above that range usually indicates added magnesium oxide. Ask any brand for the elemental assay on the certificate of analysis; TAO Daily publishes ours for every lot at trytaodaily.com/verify.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.