Magnesium Glycinate vs Citrate vs Threonate: Which Is Best? (UK)

Magnesium glycinate vs citrate: which is better?

Magnesium glycinate vs citrate: neither is better for everyone. Glycinate (also sold as bisglycinate) is gentle on the gut, so it suits daily or evening use and sensitive stomachs. Citrate has slightly stronger absorption data and draws water into the bowel, so it suits people who also want help staying regular. Both raise magnesium intake well.

Evopure’s Magnesium Glycinate Sleep Complex contains both: 1,000mg of magnesium bisglycinate and 900mg of magnesium citrate per 4.75g serving, giving 290mg of magnesium (77% NRV).

Magnesium glycinate vs citrate for sleep

Glycinate is usually the choice for a bedtime dose. It is gentle on the stomach and was the form used in a 2025 sleep trial, which found a small effect with 250mg of magnesium a day. Citrate is at least as well absorbed and there’s no evidence it disturbs sleep, but larger doses can loosen stools. Magnesium has no authorised health claim for sleep.

Below: one table comparing glycinate, citrate and threonate, then each pairing head to head, what the research really shows and how to combine forms safely. For a deep dive on one form, see our guides to magnesium glycinate, magnesium citrate and magnesium L-threonate.

Magnesium glycinate vs citrate vs threonate: comparison table

Every magnesium supplement is magnesium bound to a partner molecule. The partner changes how much magnesium you get per gram, how well it is absorbed and how it feels on your stomach.

Labels often show the weight of the whole compound, not the magnesium inside it. A “1,000mg magnesium glycinate” capsule holds only about 140mg of elemental magnesium, so always check the elemental figure. Our percentages are calculated from molecular weights and are approximate; hydrated forms contain a little less. Oxide, malate, taurate and the rest are covered in types of magnesium, and oxide on its own in our magnesium oxide guide.

If glycinate is the form for you, our best magnesium glycinate supplement guide compares UK products on elemental magnesium per serving.

Magnesium glycinate vs threonate

Choose glycinate if you want an everyday, evening-friendly way to raise your magnesium intake. It gives nearly twice the magnesium per gram, costs less per mg and has a recent placebo-controlled sleep trial behind it, though the effect was small.

Choose threonate only if you are specifically curious about the memory and focus research. It was developed to raise magnesium levels in the brain, which it did in rats. The human trials are small, short and funded by the companies behind the ingredient (see the research).

For sleep or anxiety? Glycinate is the usual first pick: cheaper, gentle on the stomach and better suited to topping up low intake. Threonate has two sleep trials with mixed results. Neither form is a treatment for insomnia or anxiety, and magnesium has no authorised health claim for sleep. More in magnesium for sleep and magnesium for anxiety.

Magnesium citrate vs threonate

Is threonate better than citrate? Not for raising your magnesium levels. Citrate has the best head-to-head absorption data of the common forms, gives roughly twice the magnesium per gram and is the most affordable well-absorbed option. Its mild laxative effect is a plus if you are prone to constipation and a drawback if you are not.

Threonate is a specialist form. Choose it only if focus and memory are your main interest and you accept the cost and the early-stage evidence. Nobody has yet compared threonate directly with citrate in a trial.

Magnesium bisglycinate vs citrate: what happens in your gut

Magnesium bisglycinate and magnesium citrate are the two most popular forms in the UK, and both are well absorbed. The real difference is what happens in your gut.

• Glycinate has little effect on the bowel, so it suits sensitive stomachs and a nightly wind-down routine. Glycine is an amino acid in its own right.
• Citrate draws water into the bowel, which is why it helps some people stay regular and why too much can cause loose stools. See magnesium for constipation.

You don’t have to choose: many products, ours included, blend the two for gentleness plus absorption. See magnesium complex vs single forms. Bisglycinate and glycinate are the same thing, by the way: each magnesium is bound to two glycine molecules.

Can you take magnesium glycinate and threonate together?

Yes. Some people take threonate in the morning and glycinate or a glycinate blend in the evening. The rule is to add up the elemental magnesium from everything you take and stay within the NHS guide of 400mg a day or less from supplements.

For example, one serving of our Magnesium Glycinate Sleep Complex (290mg) plus 2g of a threonate supplement (up to about 165mg) comes to roughly 455mg a day, which is over the guide, so you would need a smaller scoop or a lower threonate dose. A multivitamin or another magnesium product counts too, so check every label. The same applies to glycinate with citrate, or all three together.

What the research says about each form

Very few studies compare forms head to head, so it helps to know exactly what each has been tested for, and how strong that evidence is.

Citrate: the best absorption data

In a 60-day randomised, double-blind trial at the University of Reading, 46 healthy adults took 300mg of elemental magnesium a day as citrate, an amino acid chelate or oxide, or a placebo. Citrate gave the highest blood magnesium levels, both citrate and chelate beat oxide, and oxide was no different from placebo. It is one small trial, but it is why citrate is called the best-absorbed common form.

Glycinate: one recent sleep trial, small effect

In a 2025 German trial, 155 adults who reported poor sleep took 250mg of elemental magnesium a day as bisglycinate, or a placebo. After 4 weeks, insomnia scores had fallen a little more with magnesium (3.9 points vs 2.3). The authors called the effect modest. A 2026 systematic review of 12 trials of magnesium for sleep found low to very low certainty evidence and said magnesium should not be seen as a routine treatment for insomnia.

L-threonate: interesting, small and industry-funded

• Rats, 2010: raising brain magnesium with threonate improved learning and memory tests. This is the study that made threonate famous.
• Older adults, 2016: 44 adults aged 50 to 70 with memory complaints scored better on thinking tests after 12 weeks than with placebo. The researchers worked for the company developing it.
• Zhang 2022: 109 healthy Chinese adults took 2g a day of a threonate formula, also containing phosphatidylserine and vitamins C and D, for 30 days. Memory scores improved more than with placebo, but the extra ingredients mean the result can’t be pinned on threonate alone.
• Hausenblas 2024: 80 adults aged 35 to 55 with sleep problems took 1g a day or a placebo for 21 days. Questionnaire and sleep-ring scores were better with threonate. Three of the six authors worked for the ingredient supplier.
• Lopresti 2025: 100 adults aged 18 to 45 took 2g a day or a placebo for 6 weeks. Thinking scores and reaction time improved more with threonate, and some self-reported sleep measures did, but ring-measured sleep did not. The ingredient maker funded it.

So threonate’s results are worth watching, not yet strong. In 2026 magnesium L-threonate monohydrate was added to the permitted forms of magnesium for food supplements in Great Britain (Wales and Scotland in March, England in August). That makes it legal to sell; it is not a health claim.

Which magnesium for sleep, anxiety, constipation and focus?

Whichever form you take, magnesium contributes to a reduction of tiredness and fatigue, normal psychological function, normal functioning of the nervous system and normal muscle function.

Keep expectations realistic. A University of Leeds review of 18 studies found the anxiety research suggestive but of poor quality, and a Cochrane review found magnesium unlikely to make a meaningful difference to night-time leg cramps in older adults. If anxiety, brain fog or constipation is affecting your daily life or keeps coming back, speak to your GP.

How much magnesium to take, and who should check first

The NHS says adults need 300mg a day (men) or 270mg a day (women), and most people can get this from a varied diet. From supplements, 400mg a day or less is unlikely to cause harm; more than that for a short time can cause diarrhoea. The European Food Safety Authority sets a more cautious upper level of 250mg a day from supplements, and the NRV behind the % on labels is 375mg. These are elemental magnesium figures, whichever form you choose. Starting around 100 to 200mg and building up is sensible. More in how much magnesium per day.

Loose stools, nausea and stomach cramps are the most common side effects, more likely with citrate or at high doses. Speak to your GP or pharmacist first if you have kidney disease, take antibiotics (tetracyclines or quinolones), bisphosphonates for osteoporosis, diuretics or long-term acid-reducing medicines, or are pregnant or breastfeeding. See magnesium side effects.

Our supplements are for adults only, and we don’t recommend our products during pregnancy or breastfeeding. Still comparing brands? See the best magnesium supplement in the UK.

Other forms and questions: magnesium malate, magnesium taurate, magnesium orotate, powder vs tablets, how long magnesium takes to work and signs of low magnesium.

Related guides

• Wondering about liposomal glycinate? See Zooki magnesium.
• For one brand that sells both forms in the UK, see Pure Encapsulations magnesium citrate vs glycinate.
• Settled on glycinate? See the best magnesium glycinate powder and how to spot a buffered one.
• Wondering whether bisglycinate is a different form? It isn’t: our magnesium glycinate vs bisglycinate guide explains the two names.
• Want the amino acid on its own? Our guide to glycine for sleep covers the 3g trial dose and how long before bed to take it.
• For what happens after a dose, read how long magnesium stays in your body, including the glycinate half-life question.
• Choosing a form for restless legs? See magnesium glycinate for restless legs for what the small trials used.