Stand in front of a supplement shelf and you will find three or four bottles all saying magnesium, each with a different second word. Here is what those words mean and why they matter.
Magnesium is never sold on its own
Magnesium does not exist as a stable compound by itself, so it is always bound to a partner molecule. That partner determines two things: how much of the magnesium your body actually absorbs, and how well your stomach tolerates it. The number on the front of the pack tells you very little on its own.
The forms you will actually encounter
Magnesium oxide
Cheap, extremely common, and poorly absorbed. Because so much of it passes through the gut unabsorbed, it is also used as a laxative. Its appeal to manufacturers is that it contains a high percentage of elemental magnesium by weight, which makes the label look impressive.
Watch for the word buffered. It usually means a better form has been blended with oxide to raise the headline magnesium figure cheaply.
Magnesium bisglycinate
Magnesium bound to the amino acid glycine. Well absorbed and the gentlest of the common forms on the stomach, which is why it tends to be the one people take in the evening.
Magnesium citrate
Bound to citric acid. Well absorbed and reasonably priced. At higher doses it can loosen stools — useful for some people, unwelcome for others.
Magnesium malate
Bound to malic acid, which occurs naturally in fruit. Well absorbed and generally well tolerated.
Glycinate and bisglycinate are the same thing
This one causes real confusion. Magnesium glycinate and magnesium bisglycinate are the same compound — magnesium bound to two molecules of glycine. Two names, one ingredient. Do not pay more for either label.
How much do you need?
UK reference intakes are around 300mg a day for men and 270mg for women, and food should provide most of that. Green leafy vegetables, nuts, seeds, wholegrains and legumes are all good sources.
The NHS advises that up to 400mg a day from supplements is unlikely to cause harm. EFSA sets a tolerable upper limit of 350mg a day for supplemental magnesium specifically — dietary magnesium from food has no upper limit, because your kidneys handle the excess.
So which should you choose?
If you are buying one magnesium supplement, there is a reasonable case for not choosing at all. A complex containing bisglycinate, malate and citrate gives you three absorption pathways rather than betting everything on one, and avoids the tolerance issues that can come with a single high-dose form.
If you want one specific form: bisglycinate is the gentlest, citrate is the cheapest per milligram of the well-absorbed options, and malate sits between them.
Whatever you pick, the thing that matters most is what is not on the label. Check for magnesium oxide hiding in a blend, and check whether the ingredient quantities are actually declared rather than lumped into a proprietary blend.
Our approach
Our Triple Magnesium Complex uses bisglycinate, malate and citrate — 300mg elemental magnesium per two-capsule serving, no oxide, no proprietary blend, and nothing in the capsule but the actives and a plant-based shell.
Magnesium contributes to normal muscle function, normal functioning of the nervous system, normal energy-yielding metabolism, the reduction of tiredness and fatigue, normal psychological function, and the maintenance of normal bones and teeth. Food supplements are not a substitute for a varied and balanced diet and a healthy lifestyle.