What does “buffered magnesium” mean?
Buffered magnesium is when a cheaper, magnesium-dense ingredient — usually
magnesium oxide — is blended into a product to raise the elemental
magnesium number on the label. A product might say “magnesium bisglycinate”
but actually be bisglycinate mixed with magnesium oxide. The oxide is poorly absorbed,
so you get a big number on paper but less usable magnesium.
How do I know if my magnesium is buffered?
Compare the elemental magnesium claimed on the label with the most the stated compound
can provide. Magnesium bisglycinate is only about 14% elemental magnesium, so
1000 mg of pure bisglycinate can give at most ~141 mg. If the label claims more
than the compound can physically provide, it has been buffered or mislabelled. This
calculator does that maths for you in seconds.
How much elemental magnesium is in each type?
Approximate elemental magnesium by weight: magnesium oxide ~60%, hydroxide ~42%,
carbonate ~29%, chloride ~26%, sulfate ~20%, citrate ~16%, malate ~16%, bisglycinate
(glycinate) ~14%, lactate ~12%, taurate ~9%, aspartate ~8%, L-threonate ~8%,
orotate ~7%, ascorbate ~6%, gluconate ~6%.
Which magnesium is best absorbed?
Chelated and organic forms — magnesium bisglycinate (glycinate), citrate,
malate, taurate and L-threonate — are generally well absorbed and gentle on the
stomach. Inorganic forms like magnesium oxide, carbonate and hydroxide have a high
magnesium content but are poorly absorbed.
Is magnesium oxide bad?
Magnesium oxide is not dangerous, but it is poorly absorbed (studies suggest only
a few percent) and can have a laxative effect. It is cheap and magnesium-dense, which is
why it is often used to buffer products and inflate the elemental magnesium figure. If
your goal is absorption, a chelated form like bisglycinate is usually the better choice.
How does the magnesium buffering calculator work?
Enter the type and amount of the magnesium compound (the big number on the label) and the
elemental magnesium it claims (the smaller number). The calculator multiplies the compound
amount by that compound’s known elemental percentage to find the most elemental
magnesium that is physically possible. If the claim is higher than that, the product must
be buffered with a denser magnesium source such as oxide.
Where can I buy pure, unbuffered magnesium?