what-is-magnesium

Mineral Complex Series · Vitality Supplements

What is Magnesium?

Magnesium (symbol Mg, CAS 7439-95-4) is an essential dietary mineral and electrolyte your body can’t make and can’t store much of. It acts as a cofactor in over 300 enzyme reactions — from muscle and nerve function to energy and the reduction of tiredness and fatigue.

Written & reviewed by the Vitality Supplements nutrition team ·

MgElement 12
375mgUK NRV
300+Enzyme reactions
~25gIn the body

Quick Answer

Magnesium is an essential dietary mineral and electrolyte that acts as a cofactor in over 300 enzyme reactions. It contributes to normal muscle and nervous-system function, energy metabolism and the reduction of tiredness and fatigue. The UK NRV is 375mg per day, and it’s found in leafy greens, nuts, seeds, legumes and whole grains. It is a food supplement nutrient, not a medicine.

The basics

What is magnesium?

Magnesium is a mineral — chemical symbol Mg, atomic number 12, CAS number 7439-95-4 — and the eleventh most abundant element in the human body by mass. An adult carries roughly 25 grams of it, with about half to two-thirds locked into bone and most of the rest inside soft tissue and cells. Only around 1% circulates in the blood, which is part of why a simple blood test doesn’t always reflect whole-body status.

It’s classed as an essential nutrient: the body can’t manufacture it, so it has to come from food or supplements. As a cofactor, magnesium is the spark plug for more than 300 enzyme reactions — the chemical steps behind turning food into energy, building proteins, copying DNA, and letting muscles and nerves fire and then relax. It’s also one of the body’s key electrolytes, alongside sodium, potassium and calcium.

Key distinction: in supplements, magnesium is always bound to something else — an amino acid, an organic acid or a simpler salt. That partner changes how much elemental magnesium the compound delivers and how comfortably it’s tolerated. It isn’t about one form being “better” outright — they suit different priorities. See our magnesium forms explained guide for the full breakdown.

  • Chemical symbol: Mg (atomic number 12)
  • CAS number: 7439-95-4
  • Type: essential dietary mineral and electrolyte
  • In the body: roughly 25g, about half to two-thirds in bone
  • Role: cofactor in more than 300 enzyme reactions
  • UK Nutrient Reference Value (NRV): 375mg per day
  • Regulatory status: food supplement (UK)

Authorised functions

What magnesium does

In the UK and EU, only specific, reviewed wording may be used to describe a nutrient’s role. For magnesium, the authorised functions — when intake is sufficient — span energy, muscle and nerve, and structure. These describe contributions to normal function and are not claims to treat, cure or prevent any condition.

Energy & fatigue
Energy and tiredness
Contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue.
Muscle & nerve
Muscle and nervous system
Contributes to normal muscle function, normal functioning of the nervous system, and electrolyte balance.
Structure & mind
Bones, teeth & mind
Contributes to the maintenance of normal bones and teeth, normal protein synthesis, normal psychological function, and a role in cell division.

The full authorised list: normal muscle function · normal functioning of the nervous system · normal energy-yielding metabolism · reduction of tiredness and fatigue · normal protein synthesis · normal psychological function · electrolyte balance · maintenance of normal bones and teeth · a role in the process of cell division. These are the only health claims permitted for magnesium under Regulation (EC) No 432/2012 and its UK-retained equivalent.

Daily intake

How much do you need?

The figure you’ll see on a label is the NRV: 375mg per day. That’s the EU/UK reference used so “% NRV” can be shown consistently. UK dietary reference values are a little lower — around 300mg a day for men and 270mg for women — and requirements shift with age, sex, pregnancy and activity.

There’s also an upper end. The EU Scientific Committee on Food set a tolerable upper intake level of 250mg per day for magnesium taken from supplements and fortified foods — separate from the magnesium naturally present in food and water — while the UK’s Expert Group on Vitamins and Minerals set a guidance level of 400mg per day. The basis for these limits is mainly a laxative effect from large doses of certain readily dissociable salts, not systemic toxicity in healthy people.

Practical takeaway: stay within the dose printed on any supplement you take, and don’t exceed it. If you have kidney problems, take prescription medication, or are pregnant or breastfeeding, check with your doctor or pharmacist before supplementing.

Dietary sources

Where to get it

Magnesium is widespread in whole, minimally processed foods — it sits at the centre of the chlorophyll molecule, so green plants are a reliable source. Refining and processing strip much of it out, which is one reason modern diets can run lower than older ones.

  • Pumpkin & chia seeds — among the most concentrated everyday sources
  • Almonds & cashews — convenient, magnesium-dense snacks
  • Spinach & chard — leafy greens carry magnesium in chlorophyll
  • Black beans & lentils — legumes pair magnesium with fibre and protein
  • Whole grains — oats, brown rice and wholemeal retain the bran
  • Dark chocolate (70%+) — a genuinely useful, and popular, source
Food (typical serving) Magnesium % NRV
Pumpkin seeds (28g) ~156mg 42%
Chia seeds (28g) ~95mg 25%
Almonds (28g) ~80mg 21%
Spinach, boiled (½ cup) ~78mg 21%
Cashews (28g) ~74mg 20%
Dark chocolate 70%+ (28g) ~65mg 17%
Black beans, cooked (½ cup) ~60mg 16%
Quinoa, cooked (½ cup) ~60mg 16%

Approximate values; magnesium content varies by variety, soil and portion. Figures based on published food-composition data (NIH ODS). NRV = 375mg.

Worth knowing: UK National Diet and Nutrition Survey (NDNS) data suggest a proportion of some age groups, particularly teenagers and younger adults, have magnesium intakes below the lower reference nutrient intake — usually linked to diets heavier in refined and processed foods.

Supplement forms

The different forms

Because the “partner” molecule changes both elemental content and tolerability, supplement forms fall into three broad groups. Each has a slightly different profile, which is why some products combine several rather than relying on one.

Chelated
Bisglycinate & taurate
Magnesium bound to an amino acid. Generally the gentlest on digestion and well tolerated, which is why they’re popular for daily use.
Organic salts
Citrate, malate, orotate
Bound to organic acids. Well absorbed; high-dose citrate can have a mild laxative effect in some people.
Inorganic salts
Oxide & carbonate
High in elemental magnesium but less well absorbed, and oxide is the most likely to loosen the bowels at higher doses.
Mineral Complex Series · Deep dive Magnesium forms explained Bisglycinate vs citrate vs oxide and the rest — absorption, tolerability and what each form is best suited to. Mineral Complex Series · Vitality Supplements Ultimate 8 Magnesium Eight forms in one capsule — 375mg elemental magnesium (100% NRV) per serving, every dose printed on the label.

People also ask

Common questions about magnesium

What does magnesium do?

Under authorised nutrient claims, magnesium contributes to normal muscle and nervous-system function, normal energy-yielding metabolism, electrolyte balance, normal bones and teeth, and the reduction of tiredness and fatigue. It is a food supplement nutrient, not a medicine, and does not treat any disease.

Which form of magnesium is best?

There is no single “best” form — it depends on your priorities. Chelated forms like bisglycinate are gentlest; organic salts like citrate and malate are well absorbed; oxide is high in elemental magnesium but less absorbed. See our forms comparison for the detail.

Can you get enough magnesium from food?

A varied diet rich in greens, nuts, seeds, legumes and whole grains can supply magnesium. However, UK survey data show a proportion of some age groups fall below recommended intakes, often linked to more refined, processed diets.

How long does magnesium take to work?

Magnesium status responds to consistent daily intake rather than one-off use. There is no instant effect to expect; it’s best thought of as a steady, everyday part of your routine.

Usage

How to take magnesium

Vitality Supplements Ultimate 8 Magnesium provides a 1,000mg 8-form complex per serving — delivering 375mg of elemental magnesium, 100% of the UK NRV — across 2 vegan HPMC capsules. Each pouch contains 60 capsules providing 30 servings.

  • Take 2 capsules daily with water, ideally with food
  • Consistent daily use is recommended
  • Do not exceed the stated recommended daily dose
  • Consult your GP before use if pregnant, breastfeeding, on medication, or have a health condition
🔬3rd Party TestedEvery batch
🇬🇧UK ManufacturedPremium quality
🌱100% VeganHPMC capsules
↩60-Day GuaranteeNo questions asked

Full FAQ

Frequently asked questions

What is magnesium?

Magnesium (chemical symbol Mg, atomic number 12) is an essential dietary mineral and electrolyte. The adult body contains roughly 25g, with around half to two-thirds stored in bone. It acts as a cofactor in more than 300 enzyme reactions involved in energy metabolism, muscle and nerve function, and protein synthesis. It is a food supplement nutrient, not a medicine.

What does magnesium do in the body?

Under EU/UK-authorised nutrient health claims, magnesium contributes to normal muscle function, normal functioning of the nervous system, normal energy-yielding metabolism, normal protein synthesis, normal psychological function, electrolyte balance, the maintenance of normal bones and teeth, the reduction of tiredness and fatigue, and has a role in the process of cell division.

How much magnesium do I need per day?

The UK Nutrient Reference Value (NRV) used on supplement labels is 375mg per day. UK dietary reference values are lower, around 270 to 300mg for adults. Requirements vary with age, sex and life stage.

Which foods are highest in magnesium?

Good dietary sources include leafy green vegetables such as spinach and chard, nuts (almonds, cashews), seeds (especially pumpkin and chia), legumes such as beans and lentils, whole grains, and dark chocolate.

What are the different forms of magnesium?

Common supplement forms include magnesium bisglycinate, citrate, malate, L-threonate, taurate, orotate, aspartate, carbonate and oxide. They differ in how much elemental magnesium they provide and in how well they are tolerated. See our magnesium forms explained guide for a full comparison.

How much magnesium is too much from supplements?

The EU Scientific Committee on Food set a tolerable upper intake level of 250mg per day for magnesium from supplements and fortified foods, separate from magnesium naturally present in food and water. The UK Expert Group on Vitamins and Minerals set a guidance level of 400mg per day. High doses of certain readily dissociable salts can have a laxative effect. Always follow the dose on the label and do not exceed it.

When is the best time to take magnesium?

There is no single required time. Many people take magnesium with an evening meal, but morning or split dosing with food is also fine. Consistency day to day matters more than timing.

Is magnesium a medicine?

No. Magnesium taken as a supplement is a food supplement. It does not treat, cure or prevent any disease or medical condition. If you have a health concern, consult your GP.

What dose of magnesium does Vitality Supplements provide?

Vitality Supplements Ultimate 8 Magnesium provides a 1,000mg 8-form complex per serving, delivering 375mg of elemental magnesium (100% of the UK NRV), across 2 vegan HPMC capsules. Each pouch contains 60 capsules providing 30 servings.

Is Vitality Supplements Ultimate 8 Magnesium vegan?

Yes. It is encapsulated in HPMC vegan capsules and is free from gluten, GMOs, dairy, soy, artificial colours and preservatives.

Sources

References & further reading

This guide draws on peer-reviewed reviews and official UK/EU nutrition references. It is informational and not a substitute for professional medical advice.

  1. de Baaij JH, Hoenderop JG, Bindels RJ. Magnesium in man: implications for health and disease. Physiological Reviews. 2015;95(1):1–46. PubMed
  2. Schwalfenberg GK, Genuis SJ. The Importance of Magnesium in Clinical Healthcare. Scientifica. 2017;2017:4179326. PMC
  3. Barbagallo M, Veronese N, Dominguez LJ. Magnesium in Aging, Health and Diseases. Nutrients. 2021;13(2):463. PMC
  4. Commission Regulation (EU) No 432/2012 — list of permitted health claims made on foods.
  5. NIH Office of Dietary Supplements. Magnesium — Fact Sheet for Health Professionals.

Mineral Complex Series · Vitality Supplements

Ultimate 8 Magnesium

1,000mg 8-form complex · 375mg elemental (100% NRV) · 60 vegan capsules · 30 servings · Third-party tested · UK manufactured · 60-day guarantee

Shop Ultimate 8 Magnesium

This page is for informational purposes only. Magnesium taken as a supplement is a food supplement. Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. Magnesium is not a medicine and does not treat, cure or prevent any disease. The authorised nutrient functions described here apply when intake is sufficient. If you are pregnant, breastfeeding, taking medication, or have a medical condition, consult your GP before use. Store out of reach of children.