Magnesium is one mineral, but it is almost never sold as one. It is sold as magnesium something — glycinate, citrate, malate, oxide, taurate — and the something matters more than most labels let on.
If you have been comparing a night magnesium supplement in the UK against half a dozen others and found the labels unhelpful, this is why. Here is the plain version.
Magnesium is never on its own
Elemental magnesium is a reactive metal. You cannot put it in a capsule. So it is always bound to something else — a salt, an acid, or an amino acid — and that partner molecule changes three things:
- How much actual magnesium you get. The partner has weight too. A 500mg capsule of magnesium citrate is not 500mg of magnesium.
- How much of it your body absorbs. Forms differ substantially here.
- How your gut handles it. Some forms draw water into the bowel. That is a well-known property of certain magnesium salts, and it is why some are used as laxatives.
The common forms
| Form | Bound to | What that means in practice |
|---|---|---|
| Oxide | Oxygen | High magnesium by weight, and cheap. Poorly absorbed compared with the others. Long used as a laxative and an antacid. |
| Citrate | Citric acid | Better absorbed than oxide. Also osmotic — at higher doses it has a laxative effect, which is sometimes the point and sometimes not. |
|
Glycinate (bisglycinate) |
Glycine, an amino acid | Well absorbed and generally the gentlest on the gut. Lower magnesium by weight, so capsules tend to be bigger or dosed more often. |
| Malate | Malic acid | Well absorbed. Malic acid occurs naturally in fruit and is part of normal energy metabolism. |
Why a “complex” exists at all
A multi-form product is a compromise, and an honest one. Oxide is dense but poorly absorbed. Glycinate absorbs well but is bulky. Citrate sits in between and can loosen things up.
Blending forms lets a formulator balance the amount of magnesium delivered against absorption and tolerability, rather than maxing out one and living with its downside. That is the entire argument for a triple complex. It is a formulation trade-off, not a magic trick, and any brand telling you a blend is categorically superior is overselling it.
The number that actually matters
Ignore the headline milligrams on the front. Look for elemental magnesium and the %NRV on the back.
NRV is the Nutrient Reference Value — the daily benchmark. It matters for a reason most shoppers never hear: under GB rules, a product may only make a nutrient claim if it contains a significant amount, defined as at least 15% of the NRV per serving.
This is a real threshold with real consequences. Our own Night Ease contains 50mg of magnesium per capsule, which is 13% NRV. That is under the line. So we make no magnesium claim for it, and we say so on the page rather than hoping nobody checks.
What magnesium is authorised to claim
Unlike botanicals, magnesium is a mineral with a proper entry on the GB register. Where a product contains a significant amount, these are among the authorised claims, in approved wording:
- Magnesium contributes to normal muscle function.
- Magnesium contributes to the reduction of tiredness and fatigue.
- Magnesium contributes to normal functioning of the nervous system.
- Magnesium contributes to normal psychological function.
- Magnesium contributes to electrolyte balance.
Now the part you will not read on many competitor pages. Plenty of people search for magnesium for sleep. There is no authorised claim linking magnesium to sleep. Not a weak one. None.
So when a UK page tells you magnesium will help you sleep, it is making a claim it is not permitted to make. We are not going to, and you should treat sites that do with some suspicion — if they are relaxed about that rule, what else are they relaxed about?
Our Night Magnesium
Night Magnesium is a triple magnesium complex — three forms of magnesium in one daily supplement, for the balance reasons above.
We are publishing its full panel, with elemental magnesium and %NRV per serving, on the product page. Until that is up, we are not quoting claims for it, because we will not cite a claim we have not shown you the numbers for. That is the same standard we applied to Night Ease.
If you would like the wider context on what an evening formulation can and cannot say, we wrote about that in melatonin and UK sleep supplements.
Educational only, not medical advice. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle. Do not exceed the stated dose. Keep out of reach of young children. This product is not intended to diagnose, treat, cure or prevent any disease. If you are pregnant, breastfeeding, taking medication or under medical supervision, consult your doctor before use.