Magnesium Glycinate vs Citrate: Which One to Choose?

Why the Form Matters More Than the Number on the Jar

Magnesium is the most confusing category on the supplement shelf. Two jars can both promise "400 mg", but one means 400 mg of elemental magnesium and the other means 400 mg of a magnesium compound of which the actual mineral is about a sixth. The form decides three things at once: how much mineral is really in a capsule, how much of it gets through the gut, and what else you swallow alongside the magnesium.

Two forms dominate both our magnesium selection and the pharmacy shelf: magnesium bisglycinate (usually labelled just "glycinate") and magnesium citrate. Choosing between them is not a matter of taste. They behave differently in the digestive tract, they cost differently per day, and honestly they suit different people.

Let's go behind the label. What the studies actually measured, how much glycine a bisglycinate dose really delivers, what a day of each form costs in Estonia, and when you should not start with either.

Magnesium Bisglycinate: What "Chelate" Actually Means

In bisglycinate, one magnesium atom is bound to two glycine molecules. Glycine is the smallest amino acid, and the body can take it up through amino acid transporters rather than only through mineral channels. That is the real point of a chelate: the molecule does not have to compete in the gut with calcium, zinc and iron for the same transport system.

In practice this means two things. First, bisglycinate is usually the gentlest form — it does not osmotically pull water into the intestine, so it does not produce the "straight to the bathroom in the morning" effect that citrate or oxide can. Second, you get the glycine itself, which has its own action in the central nervous system.

But here is the catch the labels do not mention: a great many "magnesium bisglycinate" products are buffered. That means part of the magnesium actually comes from magnesium oxide, added so the elemental magnesium number on the label looks better. A buffered product is cheaper to make, but it throws away exactly the advantage you bought bisglycinate for. If the ingredient list says only "magnesium bisglycinate", you have the full form. If it says "magnesium bisglycinate, magnesium oxide", you have a blend.

By weight, pure bisglycinate is roughly 14% magnesium. To deliver 100 mg of elemental magnesium a capsule has to contain nearly 715 mg of the salt — which is why serious bisglycinate products come in large capsules and why the daily serving is typically 2-4 capsules, not one.

Magnesium Citrate: Cheap, Fast, and Honest About Its Side Effect

In citrate, magnesium is bound to citric acid. It dissolves well in water, which is why powders and drink mixes are almost always citrate-based — bisglycinate simply does not dissolve well enough to make a drinkable product.

That same solubility is why citrate loosens stool. Dissolved magnesium that stays unabsorbed in the intestine drags water with it. This is not a defect or poor quality, it is chemistry. For some people it is a bonus; for others it is precisely the reason they abandoned magnesium in the first place.

By weight, citrate carries more magnesium than bisglycinate (about 16% anhydrous, less in the hydrated commercial forms), and combined with cheaper raw material that makes citrate clearly the most affordable sensible choice. And unlike some other "premium forms", citrate has genuinely been measured in humans — Walker et al. (2003) compared 300 mg elemental magnesium a day over 60 days, and citrate raised red blood cell and salivary magnesium better than oxide and better than an amino acid chelate. That is an inconvenient result if you sell chelates, but it exists.

Head-to-Head Comparison

What the Research Actually Shows — and One Inconvenient Result

The strongest evidence-based claim in this whole topic is not "glycinate is best", it is "oxide is bad". Firoz and Graber (2001) measured absorption from commercial magnesium preparations and magnesium oxide landed around 4%, while the more soluble forms were several times better. If you swap a pharmacy oxide tablet for either of the forms discussed here, you have already captured most of the available benefit.

The head-to-head between bisglycinate and citrate is far weaker than the marketing implies. In Walker et al. (2003), a double-blind trial, citrate outperformed the amino acid chelate. The review by Barbagallo et al. (2021) stresses the same thing any honest retailer should say: the differences between forms are smaller than the difference between taking magnesium consistently and not. Three months of citrate every day beats three weeks of bisglycinate followed by a forgotten jar.

Where glycinate genuinely stands apart is not the magnesium, it is the glycine. Bannai and Kawai (2012) gave 3 g of glycine before bed and subjective sleep quality improved while daytime fatigue fell. Kawai et al. (2015) showed the mechanism: glycine lowers core body temperature via NMDA receptors in the suprachiasmatic nucleus, which is exactly the physiological signal that triggers sleep onset. That is real science — but it is science about glycine, not about magnesium.

The Glycine Calculation the Label Does Not Do for You

Here is a practical nuance I have never seen printed on a jar.

Pure magnesium bisglycinate is about 86% glycine by weight. If you take a dose delivering 400 mg of elemental magnesium, you have swallowed roughly 2.8 g of the salt, of which about 2.4 g is glycine. That is quite close to the 3 g dose used by Bannai and Kawai (2012). One honest caveat right here: 400 mg from a supplement is above the 250 mg upper level described below, so at a genuinely sensible 250 mg dose you get about 1.5 g of glycine — less than the 3 g used in the sleep work, but still several times what a buffered product delivers.

Now the buffered product. If half the magnesium comes from oxide, the same 400 mg elemental dose carries only about 1.2 g of glycine — half as much, and far from what was studied. You pay the glycinate price and get half a glycinate.

That is why this is one of the few times it genuinely pays to read the ingredient list, and why large capsule counts (180 or 240) are the rule for this form rather than greed. The same logic is spelled out in Magnesium Glycinate: Why It Is the Best Form for Sleep and Recovery.

What a Day of Magnesium Costs in Estonia

Supplements are worth comparing per day, not per jar. Here is the arithmetic from our shelf at the prices at the time of writing.

OstroVit Magnesium citrate 400mg + B6 90tabs costs 9.90 euros, which is 11 cents per tablet — about 22 cents a day on a two-tablet serving. This is the cheapest way in Estonia to take a sensible magnesium form consistently.

MST Magnesium Citrate 200mg 180tabs costs 25.90 euros, or 14 cents per tablet. The bigger jar means you are not back reordering every month — for consistency, that is actually a stronger argument than a couple of cents of price difference.

VitalHarmony Magnesium bisglycinate 90caps costs 12.90 euros, or 14 cents per capsule. A typical bisglycinate serving is 2-3 capsules, so about 30-45 cents a day — realistically twice the cost of citrate, which is the honest price of this form.

NOW Magnesium Glycinate 180tabs costs 29.90 euros, or 17 cents per tablet. The highest daily cost on this list, but also the longest supply.

So the range runs from roughly 20 to 50 cents a day. Over a year that is 70 to 180 euros, and that gap is exactly what you should think about before buying a form whose advantage you may not notice in your own body.

A Practical Protocol: Dose, Timing, and What Not to Combine

EFSA has set the adequate intake for adults at 350 mg a day for men and 300 mg for women (EFSA NDA Panel, 2015). That is the whole-day figure including food — an adult who eats oats, legumes, seeds and rye bread already covers a meaningful share of it. A supplement is there to top up what food leaves missing, not to carry the entire requirement. And here is the number that is almost never printed on the jar: for readily dissociable magnesium salts (exactly the ones this article is about) the tolerable upper intake level in the EU is 250 mg of elemental magnesium a day, and it applies to supplements only, not to food (EFSA NDA Panel, 2015). Magnesium from meals does not count against it. In practice that means a sensible supplemental dose is 200-250 mg a day in split servings, and 250 mg is where loose stool starts and where a long-running excess begins to push work onto the kidneys. If you have a reason to take more, that is a doctor's call, not a label's.

Timing. Citrate suits the morning or daytime. Bisglycinate suits 60-90 minutes before bed, because glycine's temperature-lowering effect then coincides with your natural sleep-onset window. If you want to try both, do not start them at the same time — change one variable at a time, or in two weeks you will not know which one did anything. Timing is covered in more depth in When to Take Magnesium: The Best Time and Form.

Start at half the dose and increase after a week. This matters especially for citrate: 400 mg at once on an empty stomach is the usual reason people conclude they "cannot tolerate magnesium". Split the dose.

What to keep apart. Magnesium reduces the absorption of tetracycline and quinolone antibiotics and of bisphosphonates — leave at least 2 hours before or 4 hours after. A large single dose of zinc or iron competes with citrate for the same transport system, so there is no point putting them in the same glass. If you use separate electrolytes for sweaty training, check how much magnesium is already in them and count it toward your daily total. The same goes for vitamin complexes, where magnesium is almost always present in some amount.

Where These Two Forms Fit Estonian Reality

A couple of local factors make this choice slightly different in Estonia than in generic English-language guides.

First, the pharmacy shelf. In an Estonian pharmacy the cheapest and most visible magnesium is still often oxide or an oxide blend, because it is cheap to produce and the number on the tablet looks impressive. If your experience with magnesium so far has been "I took it, nothing happened", there is a fair chance it was oxide, and the Firoz and Graber (2001) result explains why. Changing form is a bigger step here than raising the dose.

Second, sauna and sweat. Estonians sweat far more regularly than the average European the intake guidance was written for, but sweat mainly costs you sodium and chloride; relatively little magnesium is lost. That distinction matters: if you feel weak and crampy after a long sauna evening or a hard session, the answer is not automatically magnesium. Start with fluid and sodium, and use magnesium as steady background support rather than an acute fix.

Third, winter. In Estonia the dark-season conversation revolves almost entirely around vitamin D, which is justified, but it also means magnesium often ends up hidden inside a combination jar. If you take several supplements through the winter, add up the magnesium before you buy more.

And fourth: bisglycinate and citrate are not the only forms, just the two most sensible defaults. Malate is popular in the energy and muscle context and sits between citrate and bisglycinate on tolerability. L-threonate is sold under a brain and cognition banner, is clearly the most expensive, and has a much thinner human evidence base than the advertising suggests. Oxide has its place as a laxative, not as a general top-up. If you are weighing a more specialised form, it is worth first checking whether you can take a basic one consistently for three months.

Who Should Skip Both Forms

Anyone with reduced kidney function. Magnesium is cleared by the kidneys and can accumulate when their function is impaired. If you have diagnosed chronic kidney disease, a magnesium supplement is not a self-service decision — it goes through your doctor.

Anyone regularly taking medications whose absorption is sensitive. Thyroid medication, certain antibiotics, bisphosphonates, some cardiac drugs. No form rescues you here; timing does, and that call belongs to a doctor or pharmacist.

Anyone with inflammatory bowel disease or chronic diarrhea should skip citrate. You would be adding osmotic load to a system that is already overloaded. Bisglycinate is the only sensible option there, and even then at a small starting dose.

And an honest point a supplement shop rarely makes: if your sleep problem is persistent and serious, magnesium is not the solution. It sits alongside sleep hygiene and, when needed, a medical assessment — it does not replace them.

Common Mistakes

Confusing elemental magnesium with the amount of salt. "500 mg magnesium citrate" is not 500 mg of magnesium. Look for the line that says "of which magnesium" — and if that line is missing, that itself is information.

Taking one capsule and waiting for a result. Most serious forms are dosed in 2-4 capsules. One capsule a day is often 50-80 mg of elemental magnesium, a fifth of what you thought you were buying.

Switching form every two weeks. Red blood cell magnesium changes slowly and the studies measure over 30-60 days. Give one form at least a month.

Buying buffered bisglycinate at glycinate prices. Read the ingredients, not the product name.

Buying magnesium "for cramps" without checking anything else. Training cramps correlate more often with fluid, sodium and fatigue than with magnesium. If cramps only show up on long sweaty sessions, start with sodium. For the wider picture on forms, see Magnesium Types: Citrate, Glycinate and Oxide Compared.

FAQ

Can I take both forms on the same day?

Yes, and many people do: citrate in the morning, bisglycinate in the evening. Watch the total, though: 200 mg elemental from each is 400 mg a day, clearly above the 250 mg upper level the EU sets for supplemental magnesium (EFSA NDA Panel, 2015). A better split is 100-125 mg of citrate in the morning and 100-125 mg of bisglycinate in the evening, keeping the supplemental total inside 250 mg.

How long before I notice anything?

For sleep and relaxation, the glycine effect can show up within the first few nights. Restoring magnesium stores themselves is slow — measurable changes in red blood cell levels appeared over 60 days in Walker et al. (2003). Judge the result after a month, not a week.

Will citrate ruin my day with diarrhea?

At a normal, split dose, usually not. The risk rises sharply if you take 400 mg at once on an empty stomach. Start at half a dose with food.

Why is bisglycinate twice the price?

Producing a chelate costs more and the magnesium share is lower, so the same elemental dose needs more raw material and bigger capsules. That is a raw-material cost, not a brand markup.

Is powder better than capsules?

Not better, just different. Powders are almost always citrate-based because of solubility, which means that by choosing a powder you have already chosen the form. If you want bisglycinate, you want capsules.

Does magnesium help with muscle cramps?

The evidence is mixed and weak in the general population. If your diet is low in magnesium, topping up is a reasonable step; if it is not, look at fluid and sodium balance and training load first.

References

• Firoz, M. & Graber, M. (2001). Bioavailability of US commercial magnesium preparations. Magnesium Research, 14(4), 257-262. https://pubmed.ncbi.nlm.nih.gov/11794633/
• Walker, A.F., Marakis, G., Christie, S. & Byng, M. (2003). Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research, 16(3), 183-191. https://pubmed.ncbi.nlm.nih.gov/14596323/
• Bannai, M. & Kawai, N. (2012). New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep. Journal of Pharmacological Sciences, 118(2), 145-148. https://pubmed.ncbi.nlm.nih.gov/22293292/
• Kawai, N., Sakai, N., Okuro, M., Karakawa, S., Tsuneyoshi, Y., Kawasaki, N., Takeda, T., Bannai, M. & Nishino, S. (2015). The sleep-promoting and hypothermic effects of glycine are mediated by NMDA receptors in the suprachiasmatic nucleus. Neuropsychopharmacology, 40(6), 1405-1416. https://pubmed.ncbi.nlm.nih.gov/25533534/
• EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). (2015). Scientific Opinion on Dietary Reference Values for magnesium. EFSA Journal, 13(7), 4186. https://doi.org/10.2903/j.efsa.2015.4186
• Barbagallo, M., Veronese, N. & Dominguez, L.J. (2021). Magnesium in aging, health and diseases. Nutrients, 13(2), 463. https://pubmed.ncbi.nlm.nih.gov/33573164/