Last updated: October 2026
Magnesium glycinate is magnesium bound to the amino acid glycine. It is one of the best-tolerated forms of magnesium: well absorbed and unlikely to upset your stomach. Magnesium contributes to the reduction of tiredness and fatigue, normal muscle function and the normal functioning of the nervous system, and many people take glycinate in the evening as part of their wind-down.
This guide covers what magnesium glycinate is, its benefits (including for women), when to take it, how much, side effects, how it compares with other forms, and how to choose a good one in the UK.
What is magnesium glycinate?
Magnesium on its own is not stable, so supplements bind it to another compound. In magnesium glycinate, each magnesium is bound to glycine, an amino acid your body also makes and uses.
- Glycinate and bisglycinate are the same thing. Bisglycinate means each magnesium is bound to two glycine molecules, which is how most glycinate supplements are made.
- It is gentle. Unlike citrate and oxide, glycinate rarely loosens stools, so it suits sensitive stomachs and evening use.
- Only part of it is magnesium. Glycinate is roughly 14% magnesium by weight, so check the “elemental magnesium” figure on the label (more on this below).
Magnesium glycinate benefits
In the UK, the health benefits of magnesium that have been officially approved are that it contributes to:
- a reduction of tiredness and fatigue
- normal functioning of the nervous system
- normal psychological function
- normal muscle function
- normal energy-yielding metabolism
- electrolyte balance
- the maintenance of normal bones and teeth
Here is the honest part most brands skip: these benefits come from magnesium itself, and most research uses magnesium in general rather than glycinate specifically. What makes glycinate stand out is not a special effect but that it is well absorbed and easy to take every day, which is what actually gets magnesium into your routine.
Magnesium glycinate benefits for women
Women make up a large share of magnesium glycinate buyers, and a few times of life stand out:
PMS, bloating and water retention
In a University of Reading trial, women who took 200mg of magnesium a day for two cycles had fewer premenstrual fluid retention symptoms by the second month, including bloating, swollen hands and feet, and breast tenderness. Read more in our guides to magnesium for water retention and magnesium for PMS.
Period cramps
Magnesium is widely used for period cramps because it supports normal muscle function. Research on it for period pain is limited and mostly small, so treat it as a gentle extra rather than a replacement for pain relief.
Perimenopause and menopause
Broken sleep, tiredness and low mood are common in perimenopause. Magnesium contributes to the reduction of tiredness and fatigue and to normal psychological function, and glycinate is easy to take in the evening. See magnesium for menopause for more.
Pregnancy and breastfeeding
Magnesium needs are similar in pregnancy, but always check with your midwife or GP before taking any supplement. Our magnesium in pregnancy guide explains more.
Read more: magnesium benefits for women
Magnesium glycinate for sleep, stress and muscles
Sleep
Glycinate is the form most people choose for sleep. In a 2025 trial, adults who slept poorly and took 250mg of magnesium as bisglycinate every day had a small but real improvement in insomnia scores after four weeks compared with a placebo, with the biggest gains in people who ate the least magnesium. It is not a sleeping pill, but it can be a useful part of an evening routine. Our full guide to magnesium for sleep covers dose and timing.
Stress
Stress often shows up physically: tight shoulders, a clenched jaw, restlessness. Magnesium contributes to the normal functioning of the nervous system and normal psychological function, which is why many people make it part of a daily calm routine.
Muscles, cramps and recovery
Magnesium contributes to normal muscle function, so people who train hard, sweat a lot or get night-time cramps often take it. If restless legs are your issue, see our guide to magnesium for restless legs.
When to take magnesium glycinate
- For sleep or winding down: 30 to 60 minutes before bed.
- For general top-up or tiredness: any time of day that you will remember. Consistency matters more than the exact time.
- With food if you have a sensitive stomach.
- Away from certain medicines: magnesium can reduce how well some antibiotics, osteoporosis medicines and thyroid medicine (levothyroxine) are absorbed. Ask your pharmacist how far apart to take them.
Most people notice a difference over two to four weeks of taking it daily. For more, see the best time to take magnesium and how long magnesium takes to work.
How much magnesium glycinate should you take?
The NHS says adults aged 19 to 64 need 300mg of magnesium a day (men) or 270mg (women), mostly from food, and that 400mg or less a day from supplements is unlikely to cause harm.
The key is to read the elemental figure. Because glycinate is only about 14% magnesium, a capsule labelled “500mg magnesium glycinate” gives roughly 70mg of actual magnesium. Most people take 100 to 300mg of elemental magnesium a day, and sleep studies typically used 200 to 400mg.
Our Magnesium Glycinate Sleep Complex combines bisglycinate and citrate and gives 148mg of elemental magnesium per serving.
Magnesium glycinate side effects and who should check first
Glycinate is the gentlest form, and most people take it without problems. Possible side effects, usually at higher doses, include loose stools, nausea, stomach cramps and, occasionally, headaches or vivid dreams. Lowering the dose or taking it with food usually helps.
Speak to your GP or pharmacist first if you:
- have kidney disease, as your kidneys clear excess magnesium
- take antibiotics, osteoporosis medicines, thyroid medicine or any regular prescription
- are pregnant or breastfeeding
Magnesium glycinate vs other forms
| Form | Gentle on the gut? | Best for |
|---|---|---|
| Glycinate / bisglycinate | Yes, very | Daily use, evenings, sensitive stomachs |
| Citrate | Can loosen stools | Constipation and bloating |
| L-threonate | Yes | Interest in focus and memory (early research) |
| Malate | Yes | Daytime routines |
| Oxide | Often loosens stools | Cheap, poorly absorbed |
Plain “magnesium” on a label usually means oxide or a mix. For every form side by side, see our guide to the types of magnesium, or read magnesium L-threonate and magnesium for bloating for the citrate side.
How to choose the best magnesium glycinate in the UK
- Check the elemental magnesium per serving, not just the compound weight.
- Look for third-party lab testing and a brand that publishes its results.
- Choose a format you will actually take: capsules are quick, while powders double as an evening drink.
- Read the full ingredients. Blends may add other forms of magnesium or calming ingredients, so make sure they suit you.
- Avoid unnecessary fillers and artificial sweeteners if that matters to you.
Our Magnesium Glycinate Sleep Complex is a berry powder combining magnesium bisglycinate and citrate with L-theanine, glycine, chamomile, passionflower, hops and oat straw. It is made in the UK, vegan and third-party lab tested. Some people pair it with Sleep CBD Oil or reishi cacao in the evening, or with Flow CBD Oil during the day.
FAQs
What is magnesium glycinate good for?
Magnesium contributes to the reduction of tiredness and fatigue, normal muscle function and the normal functioning of the nervous system. Glycinate is chosen because it is well absorbed and gentle on the stomach, and many people take it in the evening to wind down.
Is magnesium glycinate better than magnesium citrate?
They suit different needs. Glycinate is gentler and better for daily or evening use. Citrate has a mild laxative effect, which makes it better if you are also constipated.
Should I take magnesium glycinate in the morning or at night?
Take it 30 to 60 minutes before bed if you want it for sleep or winding down. Otherwise, any consistent time works. Taking it every day matters more than the exact time.
How long does magnesium glycinate take to work?
Some people feel calmer within a few days, but most notice a difference after two to four weeks of daily use. Sleep studies measured results after four to eight weeks.
Can I take magnesium glycinate every day?
Yes. Most healthy adults can take it daily within the NHS guide of 400mg or less a day from supplements. Check with your GP if you have kidney problems or take regular medicines.
What are the benefits of magnesium glycinate for women?
Women often use it for premenstrual bloating and water retention, where a University of Reading trial found magnesium helped by the second month, as well as for sleep and tiredness in perimenopause. Check with your midwife or GP if you are pregnant or breastfeeding.
Can I take magnesium glycinate with CBD?
Yes, magnesium and CBD are often taken together in an evening routine. If you take prescription medicines, check with your pharmacist first, as CBD can interact with some of them.
Sources
- NHS. Vitamins and minerals: magnesium.
- Schuster J et al (2025). Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep.
- Walker AF et al (1998). Magnesium supplementation alleviates premenstrual symptoms of fluid retention. Journal of Women’s Health.
- Pattanittum P et al (2016). Dietary supplements for dysmenorrhoea. Cochrane Database of Systematic Reviews.
This guide is general information, not medical advice.
