Which Magnesium Should You Choose? A Clear Guide to Forms and Dosages
STATE editorial team · Updated Oct 2, 2026
In this article
Two bottles can both say “magnesium” in large letters and still contain very different formulas. One uses citrate, another bisglycinate, a third oxide. The figure on the front may refer to the weight of the whole compound rather than the magnesium it actually supplies. To choose clearly, start with three questions: which form, how much elemental magnesium, and in how many capsules per day?
Elemental magnesium: the first number to check
A magnesium compound combines the mineral with another substance. In citrate, it is associated with citric acid; in bisglycinate, with glycine. The weight of that compound is therefore different from the weight of magnesium itself.
If a label says “1,000 mg magnesium bisglycinate,” it does not necessarily mean “1,000 mg magnesium.” Find the magnesium line in the nutrition table, expressed in milligrams per daily serving, and its percentage of the nutrient reference value (NRV). In the EU, the labelling NRV for magnesium is 375 mg. It helps compare products; it is not a universal daily supplement dose.
Bisglycinate, citrate and oxide: what differs?
Bisglycinate binds magnesium to two glycine molecules and is used in many daily formulas. Read the full ingredients list: “buffered” can mean that bisglycinate is combined with another form, often oxide. The word alone does not tell you their proportions.
Citrate is another common form. Small comparative studies have found greater absorption from citrate than from oxide under specific conditions. That does not establish a definitive ranking of every product: dose, formulation and individual tolerance still matter.
Oxide contains a high proportion of elemental magnesium by weight. An impressive label figure does not tell the whole story about absorption. Its solubility and uptake may differ from citrate, and digestive tolerance varies with dose. Compare complete products, not isolated ingredients.
A simple checklist for reading a bottle
- Daily serving: one or two capsules, one sachet or several tablets?
- Elemental magnesium per serving: how many milligrams and what percentage of NRV?
- Exact forms: bisglycinate alone, a blend, citrate or oxide?
- Other ingredients and instructions for use.
- Your circumstances: diet, medicines, digestive sensitivity and any professional advice.
At STATE, Calm Core lists 250 mg elemental magnesium in two capsules, equal to 67% of the NRV, as buffered bisglycinate. This precise declaration makes comparison easier. You can also read the STATE science standard for our approach to ingredients and traceability.
Should “bioavailability” decide everything?
No. Bioavailability describes how much of a nutrient the body can use, but it depends on the compound, the full formulation, the amount taken and the person. Comparative trials often study particular products in relatively small groups. Treat a claim of “maximum absorption” without context or evidence on the exact formula with care.
Food remains the starting point: pulses, seeds, nuts and whole grains provide magnesium alongside other nutrients. A supplement may have a place when your diet and circumstances warrant it. It does not replace a varied diet or personalised health advice.
Frequently asked questions
Is bisglycinate always the only magnesium source?
No. Some products blend several sources. Check the full ingredients list, especially when the label says “buffered.”
Does 250 mg bisglycinate mean 250 mg magnesium?
Not necessarily. Distinguish the weight of the compound from the elemental magnesium declared in the nutrition table.
Which magnesium should I choose for persistent fatigue?
Magnesium contributes to the reduction of tiredness and fatigue under authorised EU claims, but persistent fatigue can have many causes. Speak to a healthcare professional if it continues or worsens.
Read next: foods rich in magnesium and when to take magnesium.
Sources and review
Updated 28 September 2026. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle. Do not exceed the recommended daily dose.
