Types of Magnesium: Which One Should You Take?
Oxide, citrate, glycinate, threonate… a plain-English guide to the types of magnesium, how to read a label, and which form suits most people.
In this guide
You walk into a pharmacy for “some magnesium” and walk out ten minutes later, slightly dazed, holding a tub labelled magnesium citrate. Or was it oxide? Or that “complex” with a big number on the front?
Sound familiar? You’re not alone. There are at least nine common types of magnesium on UK shelves, and most labels don’t tell you what actually matters.
So here’s the plain-English version: what each form is, what it’s known for, how to read a label in 30 seconds, and which one we think suits most people.
First, why are there so many types?
Magnesium doesn’t sit in a capsule on its own. It’s always bound to something else – an amino acid, an acid or a salt. That partner gives each form its name (glycinate, citrate, oxide…) and changes how it behaves: how much magnesium you get per gram, how well it dissolves, and how your stomach feels about it afterwards.
Research reported by the US National Institutes of Health says forms that dissolve well in liquid tend to be more completely absorbed in the gut than less soluble ones. Same mineral, very different experience.
The types of magnesium, one by one
- Magnesium oxide. The cheap one. It packs a lot of magnesium into a small amount of powder, which is why it’s used to make big numbers on the front of a tub. The catch? In one study of US supplements, only about 4% of the magnesium in oxide was absorbed, and the NIH lists oxide among the forms most commonly reported to cause diarrhoea.
- Magnesium citrate. Magnesium bound to citric acid. Research reports it’s among the better-absorbed forms, but it’s also used as a laxative and in bowel preparation before a colonoscopy. Great if that’s what you’re after. Less great before a long meeting.
- Magnesium glycinate (or bisglycinate). Magnesium bound to the amino acid glycine. It isn’t on the NIH’s list of forms most commonly linked to diarrhoea, which is a big reason people who’ve had a bad time with oxide or citrate switch to it. It’s also popular in evening routines – more on that in our magnesium for sleep guide.
- Magnesium malate. Magnesium bound to malic acid, the acid found in apples. Often taken in the morning by people who like to split their magnesium across the day.
- Magnesium taurate. Magnesium bound to taurine, an amino acid. A niche form you’ll mostly see in specialist ranges.
- Magnesium L-threonate. A newer form, bound to threonic acid. It’s the magnesium we chose for our Sleepy Time night-time blend.
- Magnesium chloride. Good bioavailability in studies, but it’s also on the NIH diarrhoea list. You’ll usually find it in sprays, oils and bath flakes.
- Magnesium sulphate. Better known as Epsom salts. One for the bath, not your breakfast – the NIH notes it’s less bioavailable than forms like citrate and chloride when taken by mouth.
- Magnesium “complexes”. A mix of several forms in one product. Sounds thorough. Often it’s a little of a fancy form for the label, plus a lot of cheap oxide to hit a big number.
Types of magnesium at a glance
| Form | Known for | Gentle on the stomach? | Where you’ll find it |
|---|---|---|---|
| Glycinate (our pick) | Everyday magnesium, bound to glycine; popular in evening routines | Not on the NIH list of forms most linked to diarrhoea | Capsules, like our Magnesium Glycinate |
| Oxide | Cheap, big numbers on the label; about 4% absorbed in one study | Among the forms most often reported to cause diarrhoea | Budget tablets and many “complexes” |
| Citrate | Well absorbed in studies | Also used as a laxative and bowel prep | Tablets, powders, fizzy drinks |
| Malate | Bound to malic acid; often a morning pick | Less studied | Capsules, blends |
| Taurate | Bound to taurine | Less studied | Specialist ranges |
| L-threonate | Newer form, often in night-time blends | Less studied | Our Sleepy Time capsules |
| Chloride | Good bioavailability in studies | On the NIH diarrhoea list | Sprays, oils, bath flakes |
| Sulphate | Epsom salts | For the bath, not for swallowing | Bath salts |
| Complexes | A mix of forms, often padded with oxide | Depends what’s in the mix | Multi-form tablets |
Magnesium glycinate vs citrate: which is better?
This is the big one people Google. Both are popular. The difference is what happens after you swallow them. Citrate is so good at drawing water into the gut that it’s used as a laxative. Glycinate isn’t known for that, which is why it’s the form most people can take every day without planning their morning around the nearest loo.
Taking magnesium in the evening as part of a wind-down? Glycinate is the one you’ll see in most evening routines. Citrate is better left for when you actually want things moving.
Magnesium oxide vs glycinate
Oxide wins on price and on the number printed on the front. Glycinate wins on almost everything else. If a cheap tub says “1,000mg magnesium” but most of it is oxide, ask yourself: how much of that is your body actually going to use?
Elemental magnesium, explained simply
“Elemental magnesium” just means the actual magnesium, not the weight of the whole compound it’s bound to. A capsule of magnesium glycinate weighs more than the magnesium inside it, because glycine is in there too.
Some labels show the compound weight in big letters and hide the elemental figure in the small print. That’s how a product can look like it gives you double what it really does. Ours is simple: 2 capsules give you 300mg of actual magnesium – 80% of your NRV (the daily reference amount on UK labels).
How does that compare with what you need? The NHS says adults aged 19 to 64 need 300mg a day (men) or 270mg a day (women), and that taking 400mg or less a day from supplements is unlikely to cause harm.
Do I need a magnesium complex?
Probably not. A complex isn’t automatically bad, but it’s the easiest place to hide cheap oxide behind a long ingredients list. If a complex doesn’t tell you how much elemental magnesium comes from each form, that’s your answer.
Check the label in 30 seconds
Look for “elemental magnesium” or “magnesium” per serving, not the weight of the compound.
Is that number for 1 capsule, or for 4? Big numbers sometimes need a handful.
Glycinate, citrate, oxide? If it just says “magnesium” or “marine magnesium”, ask why.
In a complex, see whether oxide is listed first. Ingredients are listed by weight.
Capsule or tablet? Any fillers, binders or anti-caking agents you didn’t ask for?
Why a capsule, not a tablet?
Tablets have to be pressed into shape, and that usually means binders and coatings to hold them together. Our magnesium comes in a simple vegan capsule with no fillers and no silicon dioxide. Just the magnesium glycinate you came for.
What does magnesium actually do?
Whichever form you choose, magnesium contributes to the reduction of tiredness and fatigue, normal muscle function, normal functioning of the nervous system, normal psychological function, electrolyte balance, normal energy-yielding metabolism and the maintenance of normal bones and teeth. If you’re pregnant, on medication or managing a health condition, have a quick chat with your GP or pharmacist before starting a supplement.
Questions people ask
Which type of magnesium is best?
For most people, magnesium glycinate. It’s an everyday form that isn’t on the NIH list of types most linked to diarrhoea, and it fits easily into an evening routine.
Is magnesium glycinate or citrate better for sleep?
Glycinate is the form you’ll see in most evening routines, because citrate is also used as a laxative. Our magnesium for sleep guide goes deeper.
What’s the difference between magnesium and magnesium glycinate?
Magnesium is the mineral. Magnesium glycinate is magnesium bound to the amino acid glycine – it’s one form of the same mineral.
Is magnesium oxide bad for you?
Not bad, just not much of it gets absorbed: about 4% in one study. It’s also among the forms most often reported to cause diarrhoea.
Can I take magnesium every day?
Yes. The NHS says 400mg or less a day from supplements is unlikely to cause harm, and that higher doses for a short time can cause diarrhoea. Our 2-capsule serving gives 300mg.
When is the best time to take magnesium glycinate?
Whenever you’ll remember it. Lots of people take it in the evening as part of winding down.
Can I take magnesium glycinate and Sleepy Time together?
Sleepy Time contains magnesium threonate, so add up the magnesium from both and keep your supplement total sensible. If in doubt, ask your pharmacist.
Our pick
For most people, it’s glycinate. Our Magnesium Glycinate gives you 300mg of elemental magnesium in 2 vegan capsules (80% NRV), with no fillers, no oxide padding and no maths required. Magnesium contributes to the reduction of tiredness and fatigue and to normal muscle function.
Want a full wind-down blend instead? Sleepy Time is our threonate option, with L-theanine, valerian root, lemon balm, magnolia bark and vitamin B6, taken 30–45 minutes before bed.
Related Reading
Sources & Further Reading
