Which magnesium is best?

So, which magnesium is actually best?

It depends on what you want it to do.

Full disclosure: we're biased. We sell magnesium you spray on, rub in and soak in, so take this with a pinch of (magnesium) salt. But we promise to be fair to the others too.

Magnesium works as an ion

Magnesium is biologically active in its ionic form. Only once it's been freed from whatever it's bound to can your body put it to use.

Food and supplements contain magnesium in different chemical compounds. These have to dissolve on their way through your stomach and gut to release the active magnesium ions. And that's where the compounds differ. A lot.

Through your stomach or through your skin?

Magnesium you swallow goes through your digestive system. How much gets released depends on the compound.

Magnesium on your skin goes where you put it. Tight calves or stiff shoulders? That's where the spray goes.

The rest carries on into circulation without passing through your digestive system, so it never gives you loose stools.

It's not either-or. Magnesium on the skin is a good complement to the magnesium supplements you swallow.

Magnesium oxide

Magnesium oxide (MgO) is magnesium and oxygen. It's a fairly insoluble compound that doesn't release much magnesium in the body.

What it does do is draw in water. That makes it an excellent laxative for constipation. Good to know if that's what you're after. Less good if it wasn't.

Magnesium citrate

Magnesium citrate is magnesium bound to citric acid. It dissolves well and is absorbed much better than magnesium oxide.¹

It's one of the most common forms in tablets and effervescent tablets. At higher doses it can be laxative too, but more gently than oxide.

Magnesium malate

Magnesium malate is magnesium bound to malic acid. Malic acid is part of your cells' own energy production, which is why malate is often marketed as an "energy magnesium."

Sounds logical, but the research behind it is thin. A perfectly reasonable magnesium. An energy miracle it's not.

Magnesium bisglycinate

Bisglycinate is magnesium bound to two molecules of the amino acid glycine. It's what supplement labels often call chelated magnesium.

The bond makes it gentle on the stomach, so it's a common pick for people who get loose stools from other forms.

Magnesium threonate

Magnesium L-threonate is the newest on the list. It was developed by researchers at MIT, and animal studies suggest it reaches the brain more easily than other forms. Human studies are still few.

Threonate is also a big molecule, so there isn't much magnesium per capsule. Exciting, but pricey per milligram.

Check how much magnesium you're actually getting

One thing applies to every form: magnesium is always bound to something, and the partner has weight. Magnesium oxide is about 60 percent magnesium. Threonate, less than 10 percent.

So look at how much elemental magnesium the label lists, not how much magnesium citrate or bisglycinate.

Magnesium sulfate, a.k.a. Epsom salt

Magnesium sulfate (MgSO₄) is magnesium, oxygen and sulfur. It's called Epsom salt after the spring in Epsom, England, where it was discovered in 1618.

Epsom salt is used for relaxing baths, especially foot baths. But it can sometimes cause loose stools. You can also take it by mouth as a laxative, but it's extremely bitter.

Magnesium chloride

Magnesium chloride (MgCl₂) is made of two electrolytes: magnesium and chloride. It dissolves fast in water and becomes fully ionized.

The small ions can make their way in through the skin and be taken up by muscle cells, for example, or carry on into circulation.

In water, magnesium chloride releases hydrogen ions. That lowers the pH to around 4.4 and makes the solution a weak acid.

That might sound a little scary. But it's exactly why it exfoliates the skin. That's good in itself, and it also helps the magnesium ions get through the top layer of skin more easily.

Magnesium chloride is what's in everything from Ancient Minerals: the oil, the lotion, the gel and the bath flakes.

So, which one is best?

Want magnesium in tablet form? Citrate is well absorbed, and bisglycinate is the gentlest on your stomach.

Want something for constipation? Magnesium oxide is your magnesium.

Want magnesium where you can feel it, on a tight muscle or in a warm bath? Magnesium chloride on the skin is the easiest way.

And want both? Combine them. Experiment and see what works for you.