Walk into any UK health shop and you'll see five or six magnesium supplements side by side, at prices from £4 to £40, labelled with half a dozen different forms: citrate, glycinate, bisglycinate, malate, taurate, oxide, sulphate. It's one of the most confusing supplement aisles to navigate.
The short answer is that the form matters a great deal, and not every form delivers the same magnesium to the places your body uses it. Here's the comparison.
Why magnesium is worth getting right
Magnesium is a cofactor in more than 600 enzymatic reactions in the body — a fact established in the standard physiological literature [1]. It holds a full set of authorised EU and UK health claims — it contributes to a reduction of tiredness and fatigue, to normal muscle function, to the normal functioning of the nervous system, to normal psychological function, to normal energy-yielding metabolism, to electrolyte balance, to normal protein synthesis, and to the maintenance of normal bones and teeth [2]. That's a fuller authorised claims profile than almost any other single nutrient on the market — because the biology behind magnesium is genuinely that broad.
Modern diets often fall short. Magnesium is abundant in leafy greens, nuts, seeds, legumes and whole grains, but modern food processing strips much of it, and the intensive agriculture that produces most of our vegetables has been running on depleted soil for decades. National surveys consistently find a substantial slice of UK adults below the recommended daily intake [3].
Organic vs inorganic — the first decision
The first thing on a magnesium label is not the dose; it is the chemical form. These split into two families:
- Organic salts — magnesium bonded to an organic acid or amino acid: citrate, glycinate/bisglycinate, malate, taurate, lactate, gluconate, aspartate.
- Inorganic salts — magnesium bonded to simple inorganic groups: oxide, carbonate, chloride, sulphate.
Organic forms are generally better absorbed than inorganic ones — often substantially so. That's the single most important consumer-level takeaway. A 400 mg dose of magnesium oxide and a 400 mg dose of magnesium bisglycinate do not deliver the same amount of usable magnesium [1].
The main forms, compared
Magnesium bisglycinate (glycinate) — the most popular form in the modern supplement category. Magnesium bonded to two molecules of the amino acid glycine. Absorbs well, tends to be gentle on the stomach, and is the form most people reach for when they want magnesium without digestive trade-offs. Used across the research literature on sleep and general wellbeing in adults — for instance, an 8-week RCT in elderly adults with primary insomnia found that 500 mg/day of magnesium improved Insomnia Severity Index, sleep efficiency, sleep onset latency and serum melatonin versus placebo [4].
Magnesium citrate — magnesium bonded to citric acid. Excellent absorption and bioavailability, water-soluble, and the most commonly used form in clinical research. At higher doses it can have a mild laxative effect, which is sometimes desired and sometimes not.
Magnesium malate — magnesium bonded to malic acid, a compound that plays a role in the body's energy-production cycle. Popular in supplements aimed at people with active, demanding lifestyles, partly because of the malate end of the molecule rather than the magnesium.
Magnesium taurate — magnesium bonded to the amino acid taurine. Reasonably well absorbed. Taurine itself is an interesting compound, and this combination is often chosen by people who want both at once.
Magnesium lactate — magnesium bonded to lactic acid, structurally similar to forms that occur naturally in food. Well tolerated, often chosen by people sensitive to other forms.
Magnesium chloride — an inorganic salt, but one of the better-absorbed inorganic forms. Found mostly in topical products (magnesium oil) and some oral supplements.
Magnesium oxide — the cheapest form to manufacture and the most common in budget supplements. Poorly absorbed compared with organic forms — studies have measured fractional absorption as low as 4%. If you see a high-milligram low-price magnesium capsule, it's almost certainly oxide.
Magnesium sulphate (Epsom salts) — mostly topical, in bath soaks. Not a meaningful oral supplement form.
Magnesium carbonate — slowly absorbed, mostly used for its antacid effect rather than as a supplement form.
The case for a multi-form blend
Once you look at the comparison, a reasonable question follows: if each organic form has slightly different strengths, why pick one?
That's the reasoning behind our MagActive. We blend four organic magnesium forms — citrate, bisglycinate, malate, and taurate — to deliver a total of 300 mg of elemental magnesium per serving, in the forms with the best absorption profile, from the sources the body handles most predictably.
We also include vitamin B6. That's a deliberate choice: B6 contributes to the regulation of hormonal activity, to normal red blood cell formation, and — shared with magnesium — to the reduction of tiredness and fatigue and normal psychological function [2]. B6 and magnesium share enough biochemistry that they appear together in a lot of the clinical literature, and in EU authorised claims the two nutrients support overlapping functions.
No fillers, no anti-caking agents, no colourings, no glazing agents. Capsules are straightforward — magnesium, B6, and a plant-cellulose shell.
How much magnesium do you need
The UK reference nutrient intake (RNI) for adults is roughly 300 mg per day for men and 270 mg per day for women. The EU Nutrient Reference Value (NRV) used on labels is 375 mg [3]. Most adults sit somewhere below these numbers from diet alone — particularly anyone eating a processed-food-heavy diet, drinking much alcohol, or under chronic physical or psychological load.
Supplemental doses typically run from 100 mg (top-up) to 400 mg (more substantial supplementation) of elemental magnesium per day. The "elemental" part matters — it's the actual magnesium content, not the weight of the salt. A 1,000 mg magnesium citrate capsule contains about 160 mg of elemental magnesium.
Timing. Magnesium is generally easy to take with food. Many people prefer an evening dose — consistent with magnesium's contribution to normal nervous-system function and muscle function. Splitting a larger daily dose across meals reduces any mild digestive effect.
Signs a deficit might be in play
The classic clinical-literature signs of low magnesium status include muscle cramps and twitches, daytime fatigue, disrupted sleep, and low mood [1]. None of these signs is specific — most have other common causes. Magnesium is one of the nutrients where a decent blood test (serum magnesium or, better, RBC magnesium) combined with a review of your diet gives a more useful answer than a symptom checklist.
Who should be careful
- Kidney disease. Magnesium is excreted by the kidneys. Anyone with significantly impaired kidney function should discuss supplementation with their doctor.
- Certain medications. Magnesium can interact with some antibiotics (notably tetracyclines and quinolones) and bisphosphonates by reducing their absorption. Space the doses two to four hours apart.
- Very high single doses. More than about 400 mg of well-absorbed magnesium in one go can cause loose stools. Split the dose if you need more.
In practice
The form matters more than the milligrams on the front of the pack. For everyday supplementation, an organic-salt blend — citrate, bisglycinate, malate, and taurate — gives you better absorption, better tolerability, and fuller coverage than any single form alone.
If you want that in one capsule, our MagActive pairs all four of those organic forms with vitamin B6, at 300 mg of elemental magnesium per serving, with no excipients beyond the capsule shell.
References
- de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiol Rev. 2015;95(1):1–46. PubMed: 25540137
- European Commission. EU Register of Nutrition and Health Claims Made on Foods. ec.europa.eu
- NHS. Vitamins and minerals — Others (including magnesium). nhs.uk
- Abbasi B, Kimiagar M, Sadeghniiat K, Shirazi MM, Hedayati M, Rashidkhani B. The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial. J Res Med Sci. 2012;17(12):1161–1169. PubMed: 23853635
Leave a comment
This site is protected by hCaptcha and the hCaptcha Privacy Policy and Terms of Service apply.