Magnesium Glycinate vs Citrate: Which Form Should You Choose?
An honest comparison of magnesium glycinate and citrate: absorption, gut effects, cost, label reading, NHS dose limits and medicine interactions. GUUDIES contains no magnesium.
By the GUUDIES Editorial Team · Updated 25 October 2026 · Claims checked against the GB Nutrition and Health Claims Register; sources below.
Disclosure: GUUDIES sells a daily gummy pouch. It contains no magnesium, so we have no product in this comparison.
The short answer: magnesium glycinate and magnesium citrate are both well-absorbed forms of magnesium, and both count towards your daily needs in the same way. Citrate is usually cheaper and has more published absorption data, while glycinate is often chosen by people who want a gentler option, although head-to-head research is limited.
Magnesium Glycinate vs Citrate at a Glance
| Magnesium glycinate | Magnesium citrate | Magnesium oxide (for comparison) | |
|---|---|---|---|
| What it is | Magnesium bound to glycine, an amino acid | Magnesium bound to citric acid | Magnesium bound to oxygen |
| Absorption | Generally considered well absorbed; little direct comparison data | Among the forms reported to be better absorbed than oxide | Lower absorption than citrate |
| Effect on the gut | Often described as gentle | Can loosen stools, especially at higher doses | Commonly linked to diarrhoea at higher doses |
| Tablet size | Larger tablets or more capsules for the same elemental dose | Moderate | Smallest, as it is the most concentrated |
| Typical cost | Usually higher | Usually mid-range | Usually lowest |
Absorption information is from the US National Institutes of Health, which notes that forms that dissolve well in liquid, including citrate, tend to be better absorbed than magnesium oxide (NIH ODS).
What Magnesium Does
Whatever the form, the magnesium is the same once it is absorbed. In Great Britain, the authorised health claims say that magnesium contributes to the reduction of tiredness and fatigue, to normal muscle function and to normal psychological function. These claims apply to magnesium in general. There is no authorised claim that one form is better for sleep, stress or anything else, so be wary of labels that suggest otherwise.
When People Choose Magnesium Glycinate
Glycinate (also sold as bisglycinate) is often picked by people who have had stomach upset with other forms, or who simply want a form that is less likely to affect their bowels. It is usually more expensive per milligram of magnesium, and because glycine adds bulk, you may need larger tablets or more capsules to reach the same dose. There is less independent research comparing glycinate directly with citrate than marketing might suggest.
When People Choose Magnesium Citrate
Citrate is widely available, usually cheaper than glycinate, and has more published data showing it is well absorbed. Like other magnesium salts, it can loosen stools at higher doses, because unabsorbed magnesium draws water into the bowel. Some people find that useful; others find it inconvenient. If you get loose stools, try a lower dose, split the dose through the day, or switch forms.
How to Read a Magnesium Label
The number that matters is elemental magnesium: how much actual magnesium each serving provides, not the weight of the whole compound. A capsule labelled "magnesium glycinate 500mg" may provide much less than 500mg of magnesium. Look for the line that gives magnesium in mg and its % NRV (the NRV is 375mg).
- How much do you need? The NHS says adults aged 19 to 64 need about 300mg a day (men) or 270mg a day (women), and most people can get this from food (NHS).
- How much is too much? The NHS says having 400mg or less a day from supplements is unlikely to cause any harm, and more than 400mg for a short time can cause diarrhoea.
- Food first: spinach and other leafy greens, nuts, seeds, wholegrains and pulses are good sources.
Safety and Interactions
Magnesium can reduce the absorption of some medicines, including certain antibiotics (tetracyclines such as doxycycline, and quinolones such as ciprofloxacin) and osteoporosis medicines called bisphosphonates. These usually need to be taken a few hours apart from magnesium (NIH ODS). Some medicines, such as long-term proton pump inhibitors and some diuretics, can lower magnesium levels. People with kidney disease should not take magnesium supplements without medical advice.
If you are pregnant, breastfeeding, take regular medication or have a medical condition, speak to your GP or pharmacist before choosing a magnesium supplement.
Which Should You Choose?
- Sensitive stomach or past loose stools: glycinate is a reasonable first choice.
- Want good value and well-documented absorption: citrate is a sensible choice.
- Either way: compare elemental magnesium, keep supplements to 400mg a day or less unless advised otherwise, and give it a few weeks before judging.
- Think you may be deficient? See your GP rather than guessing. Our guide to the signs of magnesium deficiency explains why.
Where GUUDIES Fits
GUUDIES contains no magnesium. If you want magnesium, choose a separate glycinate or citrate product and check it with your pharmacist if you take any medicines.
GUUDIES is one daily pouch of six pectin-based gummies for adults. The Daily Greens+ gummy carries 14 vitamins and minerals, including vitamin D3, B6 and B12, but no magnesium, iron or calcium. Five of the six gummies are vegan; Marine Collagen contains fish. Every dose is listed on our ingredients page.
Common Questions
Is magnesium glycinate or citrate better?
Neither is better for everyone. Both are well absorbed. Citrate is cheaper and better studied for absorption; glycinate is often chosen for being gentler on the stomach.
Which magnesium is best for sleep?
There is no authorised health claim for magnesium and sleep in Great Britain, and no form has a proven advantage for sleep.
Does magnesium citrate cause diarrhoea?
It can, especially at higher doses. The NHS says more than 400mg of magnesium a day can cause diarrhoea.
Can I take magnesium glycinate and citrate together?
You can, but add the elemental amounts together and keep the total from supplements at 400mg a day or less unless advised otherwise.
Does GUUDIES contain magnesium?
No. GUUDIES contains no magnesium.
Sources
- NIH Office of Dietary Supplements, Magnesium fact sheet for health professionals: ods.od.nih.gov
- NHS, Vitamins and minerals: Others (magnesium): nhs.uk
- GB Nutrition and Health Claims Register: gov.uk
Related Reading
Signs of Magnesium Deficiency · Magnesium Gummies UK Guide · Magnesium Gummies for Sleep · Supplement Label Forms Explained
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