Which Form of Magnesium Should You Take? Five Forms Compared

"Which magnesium should I take" is one of the most common supplement questions I am asked, and most of the answers online are more confident than the evidence justifies. Here is a more honest version.

First, the Thing Almost Every Article Gets Wrong

The nine authorised health claims for magnesium apply to magnesium. They do not apply differently to glycinate than to citrate. Once magnesium is absorbed, it is magnesium.

• Magnesium contributes to a reduction of tiredness and fatigue.
• Magnesium contributes to normal muscle function.
• Magnesium contributes to the normal functioning of the nervous system.
• Magnesium contributes to normal psychological function.
• Magnesium contributes to normal energy-yielding metabolism.
• Magnesium contributes to normal protein synthesis.
• Magnesium contributes to electrolyte balance.
• Magnesium contributes to the maintenance of normal bones and teeth.
• Magnesium has a role in the process of cell division.

Where forms genuinely differ is in how much magnesium they deliver and how well you tolerate them. Those are real differences and they are worth understanding. Claims that one form does something unique to your brain, your sleep or your anxiety go beyond what is authorised, and usually beyond what is demonstrated.

Elemental Magnesium: The Number That Actually Matters

A magnesium compound is magnesium bound to something else. The bound partner has weight. So "1000mg magnesium glycinate" does not mean 1000mg of magnesium — it means 1000mg of the compound, of which magnesium is a fraction.

This is the single most common way magnesium labels mislead. Always look for elemental magnesium, and be suspicious of any product that does not state it. The UK Reference Nutrient Intake for adults is around 270–300mg daily, which gives you a sense of scale.

The Five Forms

Magnesium glycinate (bisglycinate)

Magnesium bound to glycine. Generally well absorbed and notably gentle on the digestive system, which makes it a sensible default for people who have had trouble with other forms. This is why it is the form we use in our single-form product.

Magnesium citrate

Bound to citric acid. Well absorbed and one of the most extensively studied supplemental forms. It has a more pronounced osmotic effect in the gut than glycinate, which is precisely why it is also used at higher doses as a laxative. At supplemental doses most people are fine; some are not.

Magnesium malate

Bound to malic acid, a compound involved in the body's energy-producing pathways. Reasonably absorbed. The specific claims often attached to it are more mechanistic speculation than demonstrated outcome.

Magnesium taurate

Bound to taurine, an amino acid found naturally in the body. Less studied than citrate or glycinate.

Magnesium threonate

Bound to threonic acid, and the newest of the group. It attracts a great deal of attention online. The human evidence base is small, and I would treat confident claims about it with caution.

And magnesium oxide, which you should probably avoid

Cheap, high in elemental magnesium by weight, and poorly absorbed. It dominates supermarket shelves for cost reasons. If a magnesium product is unusually cheap, check whether it is oxide.

So What Should You Take?

For most people, the honest answer is: a well-absorbed form, at a meaningful elemental dose, taken consistently. Consistency matters more than the choice between glycinate and citrate.

• Sensitive digestion, or you have reacted to magnesium before — glycinate.
• You want breadth across forms — a complex. Our Magnesium Complex 5-in-1 provides 400mg across all five forms above.
• You want one thing, simply — Magnesium Glycinate at 300mg elemental.

Practical Notes

• Loose stools are the usual sign of too much. Reduce the dose rather than stopping altogether.
• Magnesium can interfere with the absorption of certain antibiotics and other medicines — separate doses by a few hours and check with your pharmacist.
• If you have reduced kidney function, speak to your GP before supplementing magnesium at all.