Two bottles, two words, and in most cases one compound.
The distinction is real chemistry and it is almost never the distinction a buyer is being sold. What separates two glycinate products on a shelf is usually something else entirely, and the panel gives it away in four seconds.
What is the difference between magnesium bisglycinate and magnesium glycinate?
Bisglycinate is the precise name: one magnesium ion chelated to two glycine molecules, which is what the prefix records. Glycinate is the common commercial shorthand for the same compound. On the overwhelming majority of labels the two words describe an identical ingredient, and the choice between them is a naming convention.
So the answer to the question as usually asked is anticlimactic: they are the same thing, and a brand using the longer word is being more precise rather than selling something else. The interesting question is one word further along.
What does a buffered magnesium glycinate mean?
Buffered means magnesium oxide has been blended in with the chelate. It is a legitimate manufacturing choice — oxide is cheap and dense, so a buffered product reaches a given elemental figure in a smaller capsule. It stops being legitimate when the front of the bottle says glycinate and the blend is not disclosed as a blend.
That is the difference worth catching, and it is not a naming question at all. A buffered product is arithmetically visible, because oxide carries roughly 60% magnesium by weight and a bisglycinate carries about 14% at most. Blend the two and the fraction rises above what a pure chelate can reach.
How do you tell them apart on a panel?
One division. Take the elemental magnesium figure and divide it by the compound weight of the magnesium ingredient. A pure bisglycinate lands at or under about 14%. Anything meaningfully above that, labelled as pure glycinate, is either a blend, a different compound, or a panel that has not been checked.
| What the fraction reads | What it means |
|---|---|
| about 11 to 14% | a real bisglycinate |
| about 20 to 40% | a buffered blend |
| about 60% | oxide, whatever the front says |
| not computable | no elemental figure printed — walk |
These are formula-weight fractions — arithmetic on the compound, not results from a laboratory. A real capsule usually lands under its form’s ceiling because of bound water and excipients. Landing above the ceiling is the signal.
Run it on ours. Night Work is 275 mg of elemental magnesium from 2,500 mg of magnesium glycinate across three capsules. 275 ÷ 2,500 is 11%, under the roughly 14% ceiling, which is what a genuine chelate looks like once it is in a capsule with everything else a capsule contains.
Why does a real glycinate take more capsules?
Because 14% is a low fraction and volume is the price of it. Reaching 275 mg of elemental magnesium from a chelate takes 2,500 mg of compound, and 2,500 mg of powder does not fit in one capsule. Three is what the arithmetic costs. A one-capsule product claiming the same elemental dose has not done the arithmetic.
Which reframes the capsule count from a liability into the proof. A small capsule at a large elemental figure is the thing to be suspicious of, not the large serving. The oxide fraction is the only way to make that shape work, and a product built that way should say so on the front.
What the research does not show
Precise absorption percentages should be treated with suspicion, including the ones that favour our own form. Figures comparing chelated and inorganic magnesium circulate quoted to the decimal point. The underlying comparisons are small, use different methods and different endpoints, and do not agree closely enough to support a single number. The direction is reasonably consistent; the precision is invented downstream.
What holds up is narrower. Poor solubility means a substantial share of an oxide dose is not absorbed, and chelated forms are generally better tolerated at comparable elemental doses. That is enough to choose a form. It is not enough to quote a ratio.
And magnesium’s established physiological roles are the strongest thing about it — normal muscle function, normal nervous-system function, normal energy metabolism.* Those are the honest basis for taking it, and they are the whole of what TARE claims for Night Work.
The number that costs us, since we are running divisions on other people’s panels: Night Work’s certificate measured magnesium at 96.91 mg per capsule against a specification of greater than 91.6 mg. Our serving is three capsules, so the measured serving is 290.7 mg against the 275 mg the label claims. We claim less than the document found, and both figures are on Testing & Certification.
More in this cluster: glycinate against oxide, the long version, 275 mg from 2,500 mg, and the 350 mg ceiling and how a stack reaches it.