Last updated: October 2026
A magnesium complex is a supplement that combines two or more forms of magnesium, such as glycinate and citrate. Its benefits are those of magnesium itself, such as contributing to the reduction of tiredness and fatigue. There’s no proof a blend absorbs better than one good form; what matters is the forms used and the total magnesium.
Below: what’s in a typical complex, the benefits, complex vs single form, how to read the label, and exactly what’s in ours.
What’s in a magnesium complex?
| Form | Why it’s included |
|---|---|
| Glycinate (bisglycinate) | Well absorbed, gentle on the stomach |
| Citrate | Well absorbed; adds magnesium cheaply; can loosen stools at higher doses |
| Malate | Often marketed for energy; no better evidence than other forms |
| L-threonate | Marketed for the brain; very little magnesium per dose |
| Oxide | Packs in a big number cheaply but is poorly absorbed; a warning sign if it’s the main form |
Many complexes also add other ingredients such as L-theanine, glycine, B6 or herbs. See types of magnesium.
Magnesium complex benefits
Magnesium has authorised health claims in the UK. It contributes to:
- the reduction of tiredness and fatigue
- normal muscle function
- normal functioning of the nervous system
- normal psychological function
- electrolyte balance and normal energy-yielding metabolism
- the maintenance of normal bones and teeth
Beyond these, research on magnesium for sleep, anxiety and cramps is small and mixed. See magnesium for sleep, magnesium for anxiety, magnesium for muscle pain and magnesium for bloating.
Complex vs a single form
| Magnesium complex | Single form | |
|---|---|---|
| Absorption | Depends on the forms; no proof blends beat one good form | Glycinate or citrate alone are well absorbed |
| Stomach comfort | Mixing glycinate with citrate can balance gentleness and dose | Glycinate is gentlest; citrate can loosen stools |
| Extras | Often includes other ingredients | Usually just magnesium |
| Watch out for | Oxide used to bulk up the number | Low doses per capsule |
For a full comparison, see glycinate vs citrate vs threonate and why many magnesium supplements are wasted.
How to read a magnesium complex label
- Find total elemental magnesium in mg and %NRV in the nutrition table.
- Check which forms are listed first; ingredients are listed by weight.
- Watch for oxide as the main form.
- Check the extras against any medicines you take.
What’s in our Magnesium Glycinate Sleep Complex
Our Magnesium Glycinate Sleep Complex is a powder drink for the evening. Each serving gives 148mg of magnesium from bisglycinate and citrate, with glycine, L-theanine, chamomile, passionflower, hops and oat straw, natural berry flavour, beetroot powder, stevia and inulin. It contains no oxide and no threonate, and it’s vegan.
Dose and safety
- Daily needs: 300mg (men) or 270mg (women), mostly from food, says the NHS.
- Supplements: 400mg a day or less is unlikely to cause harm.
- How long: give it a few weeks. See how long magnesium takes to work.
- Check first if you have kidney disease, or take antibiotics or osteoporosis medicines.
- Pregnancy and breastfeeding: we don’t recommend our products during pregnancy or breastfeeding.
FAQs
What is a magnesium complex?
A supplement that combines two or more forms of magnesium, such as glycinate and citrate, often with other ingredients.
Is a magnesium complex better than magnesium glycinate?
Not necessarily. There’s no proof blends absorb better than one good form. The forms used and the total magnesium matter more.
What are the benefits of a magnesium complex?
Magnesium contributes to the reduction of tiredness and fatigue, normal muscle function and normal psychological function.
Does a magnesium complex help with bloating?
Citrate can ease constipation, which sometimes causes bloating, but magnesium isn’t proven for bloating itself. See our guide to magnesium for bloating.
When should I take a magnesium complex?
Any time of day; many people take it in the evening. Consistency matters more than timing.
Sources
- NHS. Vitamins and minerals: magnesium.
- Walker AF et al. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnes Res, 2003.
- Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res, 2001.
