Magnesium glycinate: the complete guide
What magnesium glycinate is, what magnesium does, what the sleep research shows, glycinate vs citrate, how much to take and who should check first.
- Written by
- Amy D
- Reviewed by
- Nooroots team
- Last updated
- Reading time
- 10 min read
Quick answer
Magnesium glycinate is magnesium bound to the amino acid glycine, one of the organic forms of magnesium. Magnesium helps reduce tiredness and fatigue and supports normal muscle and nervous system function. Adults need 270 to 300 mg a day, and up to 400 mg from supplements is unlikely to cause harm.
Key points
- Label: look for elemental magnesium, not the glycinate weight.
- Daily need: UK adults need 270 to 300 mg of magnesium.
- Sleep: one 2025 trial found a small benefit from 250 mg a day.
- Forms: organic forms such as citrate and chelates beat oxide.
- Limit: more than 400 mg a day from supplements can cause diarrhoea.
What is magnesium glycinate?
Magnesium glycinate is magnesium joined to glycine, a small amino acid your body also makes. You'll also see it called magnesium bisglycinate, because each magnesium is usually paired with two glycines.
Joining a mineral to an amino acid like this is called chelation. Glycinate is one of the "organic" forms of magnesium, like citrate and malate. Cheaper forms such as magnesium oxide are called inorganic.
Most of its weight is glycine, not magnesium. So always look for the elemental magnesium on the label: the amount of magnesium itself.
What does magnesium do in the body?
Magnesium is a mineral your body needs every day. It's involved in hundreds of processes, from making energy to moving muscles. UK law allows these health claims for it, because the evidence has been formally checked [6]:
- Energy. Magnesium contributes to a reduction of tiredness and fatigue, and to normal energy-yielding metabolism.
- Mind and nerves. Magnesium contributes to normal psychological function and to normal functioning of the nervous system.
- Muscles. Magnesium contributes to normal muscle function and to electrolyte balance.
- Bones and teeth. Magnesium contributes to the maintenance of normal bones and teeth.
- Cells. Magnesium contributes to normal protein synthesis and has a role in the process of cell division.
These apply to magnesium in any form, as long as a product gives enough of it. They are the main reason people take a magnesium supplement.
How much magnesium do you need a day?
The NHS says adults aged 19 to 64 need 300 mg a day for men and 270 mg for women [1].
You should be able to get this from a varied diet. Good sources include spinach, nuts and wholemeal bread [1]. A supplement can help if your diet is low in these foods.
From supplements, 400 mg a day or less is unlikely to cause harm. Taking more than that for a short time can cause diarrhoea [1].
How to read a magnesium glycinate label
Labels show two numbers that are easy to mix up: the weight of the compound and the magnesium in it. Only the second counts towards your daily need.
| On the label | Compound | Magnesium |
|---|---|---|
| Pure magnesium bisglycinate | 1,000 mg | about 140 mg |
| Nooroots Triple Magnesium glycinate, citrate and malate, 3 capsules |
2,150 mg | 301 mg |
| NHS daily need for adults | 270 to 300 mg |
Magnesium glycinate benefits
The firm benefits are the ones above, and they come from magnesium itself. Research on glycinate is newer and smaller. Each finding has a label: Strong (several good trials agree), Moderate, Early (one or two small trials) or Mixed.
Tiredness and energy Strong
Magnesium's role in reducing tiredness and fatigue is an authorised health claim. The evidence behind it covers magnesium in general, not glycinate alone [6].
Sleep Early
In a 2025 German trial, 155 adults aged 18 to 65 who said they slept poorly took magnesium bisglycinate or a placebo every day for 4 weeks. The dose gave 250 mg of magnesium. Sleep scores improved a little more with magnesium, by 3.9 points against 2.3 [2].
A 2026 review of 12 trials of magnesium in various forms found the sleep results were inconsistent, and the evidence was weak [3]. So magnesium for sleep is promising but not settled, and may help most if your diet is low in it.
Muscle cramps: little effect
A 2020 Cochrane review of 11 trials found magnesium is unlikely to make a real difference to night-time leg cramps in older adults. Cramps were barely less frequent than with a placebo [4]. Magnesium still supports normal muscle function.
Mood and stress: authorised claim, little glycinate research
Magnesium contributes to normal psychological function and to the normal functioning of the nervous system. Those are authorised claims for magnesium in any form [6].
Beyond that, there are few good trials of magnesium glycinate on mood or stress in healthy adults. So treat claims that glycinate is a "calming" form with care: the calming link comes from magnesium, not from the glycine.
What the research says
| Study | People | Dose a day | Length | Result |
|---|---|---|---|---|
| Schuster 2025 [2] | 155 adults who slept poorly | 250 mg magnesium as bisglycinate | 4 weeks | Small sleep improvement vs placebo |
| Lopresti 2026, review [3] | 12 trials in adults | Various | Various | Inconsistent sleep results |
| Garrison 2020, Cochrane review [4] | 11 trials, 735 people | Various | Various | Little effect on leg cramps |
| Walker 2003 [5] | 46 healthy adults | 300 mg magnesium in three forms | 60 days | Citrate and chelate absorbed better than oxide |
Who might benefit from magnesium?
Most adults can get enough magnesium from food [1]. A supplement makes most sense if your diet is low in it:
- Few magnesium-rich foods. If you rarely eat leafy greens, nuts, seeds or wholegrains, you may fall short.
- Poor sleep and a low intake. In the bisglycinate trial, people who ate little magnesium seemed to gain most [2].
- Busy weeks and tiredness. Magnesium contributes to a reduction of tiredness and fatigue [6].
If you have symptoms that worry you, such as ongoing tiredness or muscle twitches, see your GP rather than guessing with supplements.
Magnesium glycinate for sleep
The main bisglycinate sleep trial used 250 mg of magnesium a day for 4 weeks [2]. That's within the NHS limit of 400 mg a day from supplements [1].
- Take it in the evening. There's no proof that timing matters, but it fits a wind-down routine.
- Keep it going for 4 weeks. The trial measured its result at 4 weeks [2].
- Look at your diet too. People who ate little magnesium seemed to gain most [2].
Magnesium glycinate vs citrate vs malate
Forms differ mainly in how well they're absorbed. Few trials compare them directly.
| Form | What it is | What the research shows |
|---|---|---|
| Glycinate | Magnesium joined to glycine | Its chelate family was absorbed better than oxide in a 60-day trial [5] |
| Citrate | Magnesium joined to citric acid | Raised blood magnesium the most in the same trial [5] |
| Malate | Magnesium joined to malic acid, found in fruit | Little research comparing it with other forms |
| Oxide | Inorganic, cheap, high in magnesium by weight | Absorbed no better than placebo in that trial [5] |
In practice, an organic form at a sensible dose that you take every day matters more than which one you choose. Some products combine several forms.
Bisglycinate and buffered glycinate
Magnesium glycinate and magnesium bisglycinate usually mean the same thing. "Bisglycinate" just spells out that each magnesium is paired with two glycines.
"Buffered" glycinate is different. It's glycinate mixed with magnesium oxide, which raises the magnesium in each capsule and lowers the cost. Oxide is the form that was absorbed no better than placebo in the 60-day trial [5].
Check the ingredients list. If magnesium oxide appears, the product isn't pure glycinate.
How to choose a supplement
- Check the elemental magnesium. It should be stated per daily dose. Around 200 to 300 mg covers most of an adult's daily need.
- Check the form. The label should name it: glycinate, bisglycinate, or a mix of organic forms.
- Check the dose size. Magnesium glycinate is bulky, so a full dose often takes two to four capsules.
- Stay under 400 mg. Add up all your supplements, including multivitamins [1].
Magnesium glycinate side effects
At normal doses magnesium is well tolerated. The usual side effects are stomach upset and diarrhoea, which become more likely above 400 mg a day [1]. In the Cochrane review, minor side effects, mostly digestive, were a little more common with magnesium than with the placebo [4].
- Kidney problems. Ask your GP first, because your kidneys clear extra magnesium.
- Some medicines. Antibiotics, thyroid medicine and medicines for bone strength may need to be taken a few hours apart. Ask your pharmacist.
- Pregnancy or other regular medicines. Ask your GP or pharmacist first.
Where Nooroots fits
Nooroots Triple Magnesium combines three organic forms: glycinate (1,150 mg), citrate (500 mg) and malate (500 mg). Together they give 301 mg of magnesium, 80% of the daily reference intake, in three capsules a day.
Triple Magnesium's magnesium helps reduce tiredness and fatigue, and supports normal muscle function, the normal functioning of the nervous system and normal psychological function. Food supplements should not replace a varied, balanced diet and a healthy lifestyle.
Coming soon. Triple Magnesium isn't on sale yet.
Frequently asked questions
What are the side effects of magnesium glycinate?
Mostly stomach upset and loose stools, especially above 400 mg a day from supplements [1].
How many mg of magnesium glycinate should I take a day?
Go by the magnesium, not the glycinate. Adults need 270 to 300 mg a day in total, and up to 400 mg from supplements is unlikely to cause harm [1].
Is magnesium glycinate better than citrate?
Neither is clearly better. In one trial, citrate and an amino-acid chelate, the family glycinate belongs to, both beat oxide for absorption, and citrate raised blood levels most [5].
Can I take magnesium glycinate every day?
Yes. Magnesium is needed daily, and up to 400 mg a day from supplements is unlikely to cause harm [1].
Does magnesium glycinate make you sleepy?
Not in the way a sleeping pill does. In the sleep trial, it gave a small improvement in sleep scores over 4 weeks [2].
Is magnesium glycinate good for your muscles?
Magnesium contributes to normal muscle function [6]. For night-time leg cramps in older adults, though, a Cochrane review found little benefit [4].
Is magnesium glycinate better than malate?
There's little research comparing them. Both are organic forms, and some products, like ours, combine glycinate, citrate and malate.
Can you take magnesium glycinate with ashwagandha?
Yes, no interaction is known. See Ashwagandha and magnesium: can you take them together?
Related articles: Ashwagandha and Lion's mane.
References
Every study here is listed so you can read it yourself. This guide is for general information and doesn't replace advice from your GP or pharmacist. We review it when new research is published.
- NHS. Vitamins and minerals: others (magnesium section). Accessed 14 October 2026. nhs.uk/conditions/vitamins-and-minerals/others
- Schuster J et al. (2025). Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep 17: 2027–2040. doi:10.2147/NSS.S524348
- Lopresti AL et al. (2026). Magnesium supplementation for sleep in adults: a systematic review of randomized controlled trials. Journal of Dietary Supplements 23(5): 553–581. doi:10.1080/19390211.2026.2719670
- Garrison SR et al. (2020). Magnesium for skeletal muscle cramps. Cochrane Database of Systematic Reviews 9: CD009402. doi:10.1002/14651858.CD009402.pub3
- Walker AF et al. (2003). Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research 16(3): 183–191. PMID 14596323
- Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register. gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register
