Magnesium glycinate is a form of magnesium bound to glycine, an amino acid. It is also called magnesium bisglycinate, because each magnesium ion is bound to two glycine molecules.

It is one of several forms used in supplements, alongside citrate, oxide, malate and others.

Yes. The two names describe the same compound and are used interchangeably on labels.

Bisglycinate is the more precise chemical name, and glycinate is the more common name on the front of a pack.

Elemental magnesium is the weight of the magnesium itself, not the weight of the compound it is bound to. It is the figure that tells you how much magnesium you are actually taking.

Pure magnesium bisglycinate is only around 14% magnesium by weight, so a capsule with 500mg of the compound would normally provide roughly 70mg of magnesium.

They are different compounds. Citrate is bound to citric acid and is often used for its laxative effect at higher doses, while glycinate is generally considered gentler on digestion.

We are not aware of strong head-to-head trials showing that one is clearly better absorbed or more effective than the other.

Magnesium oxide contains a much higher percentage of magnesium by weight but is generally considered less well absorbed and more likely to loosen stools.

Some glycinate products are "buffered" with oxide to reach a higher elemental figure, which should be declared in the ingredients.

Magnesium contributes to normal energy-yielding metabolism, normal muscle function, normal functioning of the nervous system and normal psychological function, and to a reduction of tiredness and fatigue.

It also contributes to electrolyte balance, normal protein synthesis and the maintenance of normal bones and teeth, and has a role in cell division.

The best choice depends on what matters to you. Our overall pick is Charava Magnesium Glycinate, because it is the simplest to take: one vegan, UK-made capsule a day with a stated 100mg of magnesium. The Longevity Shop is commercially connected to Charava, which you should weigh when reading our rankings.

For an oxide-free 200mg, look at Cytoplan. For the best value capsule, Pure Encapsulations. For the lowest price, Bulk.

Look for a stated elemental magnesium figure, a disclosed form with any added oxide declared, a sensible daily amount, few other ingredients and clear manufacturing and testing information.

Also check how many capsules or tablets make up a serving, because that changes both convenience and cost.

Not necessarily, but it is a different product from a pure glycinate. Oxide raises the elemental magnesium per capsule, and some buyers prefer a single-form product.

What matters is that the label declares it. Cytoplan states that its product is unbuffered, and Bulk declares that its tablets are buffered.

No. Most people can meet their needs from food plus a modest top-up, and high doses of any magnesium can cause diarrhoea.

UK guidance treats 400mg or less a day from supplements as unlikely to cause harm, so more is not automatically better.

The elemental magnesium you take matters, not the number of capsules. One capsule is simply easier to keep up as a daily habit.

In this guide Charava and Pure Encapsulations provide a serving in one capsule, while Cytoplan, Viridian and Bulk need two capsules or tablets.

At the time of writing, Charava is £14.99 for 60 capsules, Cytoplan £14.99 for 60 capsules, Viridian about £16.05 for 60 capsules, Pure Encapsulations about £17.76 for 90 capsules and Bulk £5.99 for 60 tablets.

Compare cost per 100mg of magnesium as well as per bottle: we calculate roughly £0.25 for Charava and Cytoplan, £0.16 for Pure Encapsulations, £0.27 for Viridian and £0.10 for Bulk.

Follow the directions on the product you choose. UK guidance is that adults need 300mg (men) or 270mg (women) of magnesium a day from all sources, and that 400mg or less a day from supplements is unlikely to cause harm.

Remember to count magnesium from every supplement you take, including multivitamins.

There is no good evidence that timing matters. Charava suggests an afternoon or evening capsule, and Cytoplan suggests taking it with food.

The best time is whenever you will remember it every day.

Directions differ between brands, and several suggest taking it with food. Taking it with a meal is a sensible choice if your stomach is sensitive.

Follow the instructions on the product you buy.

Magnesium is a mineral supplement, not a medicine, and it does not work on a fixed timetable. Responses vary, and some people notice nothing.

Studies of magnesium for sleep ran for weeks, not days, so do not expect a quick effect.

Magnesium can interact with some medicines, including some antibiotics and bisphosphonates, and may need to be taken at a different time of day.

If you take prescribed medication or have a health condition, check with your pharmacist or GP before starting.

The evidence is limited. A 2021 systematic review of three small trials in 151 older adults with insomnia found people fell asleep about 17 minutes faster on magnesium than on placebo, but judged the evidence to be of low quality.

No health claim for sleep is authorised for magnesium, and the trials did not test glycinate specifically.

The authorised wording is that magnesium contributes to normal psychological function. That is not the same as treating stress or anxiety.

If you are struggling with anxiety or low mood, speak to your GP rather than relying on a supplement.

Magnesium contributes to normal muscle function, but evidence that supplements prevent cramps is mixed, and results differ between groups of people.

If you have frequent or severe cramps, speak to your GP, because they can have causes that a supplement will not address.

Yes. Magnesium has authorised claims including contributing to a reduction of tiredness and fatigue, normal muscle function, normal functioning of the nervous system and normal psychological function.

A product must provide at least 15% of the nutrient reference value per daily serving, about 56mg, to use them. Claims about sleep quality or stress relief are not authorised.

For most healthy adults, UK guidance is that 400mg or less a day of magnesium from supplements is unlikely to cause harm.

There is not enough evidence to say what the effects might be of taking high doses for a long time.

The most common side effect of high doses of any magnesium is diarrhoea, and some people also report nausea or stomach discomfort. Glycinate is generally considered gentler than some other forms.

If you have side effects, reduce the dose or stop, and speak to a pharmacist if they persist.

Speak to your GP or pharmacist first if you have kidney problems, are pregnant or breastfeeding, are under 18, take prescribed medication or are being treated for a medical condition.

The kidneys remove excess magnesium, so reduced kidney function raises the risk of taking too much.

Many people take it daily within the amounts on the label, and UK guidance treats 400mg or less a day from supplements as unlikely to cause harm.

It is worth asking whether you need it at all, because most people can get what they need from a varied diet.

Glycine used in supplements is usually made synthetically, so the compound itself need not be animal-derived. The capsule or tablet matters: Charava uses a vegetable (hypromellose) capsule and Viridian is described as vegan.

Check the label of any other product for capsule and ingredient details.

Charava is the simplest product here to take: one vegan, UK-made capsule a day with a stated 100mg of elemental magnesium, and a large base of customer reviews on its own site.

It is not the strongest or the cheapest per 100mg, and the product page does not say whether another magnesium compound is used. The Longevity Shop is commercially connected to Charava, which is disclosed at the top of this page.

No. The Longevity Shop is commercially connected to Charava and may earn revenue from purchases made through links on this page.

We disclose that relationship, explain our assessment criteria and state the trade-offs of every product, including Charava's, so you can make your own judgement.

We selected magnesium glycinate and bisglycinate supplements available to UK buyers that represent the main choices: a simple single-capsule product, a well-known practitioner brand, an unbuffered 200mg, a vegan high-potency option and a low-cost buffered tablet.

Each was assessed on elemental dose, form, ingredients, manufacturing information and value, using manufacturer and retailer information available in October 2026.