Magnesium

All Supplements

What Is Magnesium?

Magnesium is an essential mineral involved in over 300 enzymatic reactions in the body, including energy production, muscle contraction, nerve function, and protein synthesis. Despite its importance, surveys consistently show that a significant proportion of the population does not get enough from diet alone. Rich food sources include dark leafy greens, nuts, seeds, and whole grains.

The Different Forms

Not all magnesium supplements are the same. The form you choose matters significantly for both absorption and effects:

• Magnesium Glycinate — bonded to glycine, an amino acid with calming properties. Best for sleep, relaxation, and recovery. Well absorbed with minimal digestive side effects. This is the top recommendation for most athletes.
• Magnesium Citrate — good general-purpose option with decent absorption. Slightly more likely to cause loose stools than glycinate, which is actually useful if you struggle with regularity.
• Magnesium Oxide — the cheapest and most common form, but poorly absorbed (only ~4% bioavailability). Most of it passes straight through you. Avoid this unless you specifically want a laxative effect.
• Magnesium L-Threonate — may cross the blood-brain barrier more effectively. Some research suggests cognitive benefits, but it is expensive and the evidence is still emerging.

How It Works

Magnesium supports muscle relaxation by regulating calcium flow into muscle cells. When magnesium is low, muscles may contract more than necessary — leading to cramps, tightness, and poor recovery. It also plays a role in melatonin production and GABA receptor activity, which is why supplementing in the evening may help with sleep quality.

What the Research Says

Research supports magnesium supplementation for people who are deficient, which is a large portion of the population. Studies show it can improve sleep quality, reduce muscle cramps, and support exercise performance. The evidence is strongest for correcting deficiency rather than “super-dosing” — once your levels are adequate, more is not better.

Who Should Take It

Anyone who trains regularly, sleeps poorly, or experiences muscle cramps. Hard training increases magnesium loss through sweat, and many diets fall short of the recommended 300-400mg daily intake. If you eat plenty of leafy greens, nuts, and seeds, you may already be getting enough.

Who Should Avoid It

People with kidney disease should consult their doctor, as the kidneys regulate magnesium excretion. If you take antibiotics, bisphosphonates, or certain heart medications, check for interactions. Start with a lower dose (200mg) and increase gradually to assess tolerance.

Vegan?

Magnesium supplements are vegan-friendly. The mineral itself is sourced from natural deposits or synthesised, with no animal-derived ingredients. Check capsule shells if you prefer tablets — some use gelatin, but most brands now offer plant-based cellulose capsules.

Where to Buy

• Myprotein Magnesium Tablets — from £5.99
• Bulk Magnesium Bisglycinate — from £7.99
• Amazon — Nutravita Magnesium Glycinate — from £11.99

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