Magnesium glycinate vs citrate: what's actually different

Magnesium glycinate and magnesium citrate are both common supplement forms, but they differ in elemental magnesium per gram and in the human evidence behind them. Citrate is about 16% magnesium by weight and is the only form with a positive absorption trial against oxide in healthy adults; glycinate is about 11–14% and has not beaten citrate in the one trial that compared them directly.

The two forms, side by side

Magnesium glycinate and magnesium citrate compared on chemistry, typical use and evidence.

	Magnesium glycinate	Magnesium citrate
Formula	C4H8MgN2O4	Mg3(C6H5O7)2
Molar mass	172.42 g/mol (PubChem CID 84645)	451.12 g/mol (PubChem CID 6099959)
Elemental magnesium by weight	~11–14%	~16%
Typically sold for	General daily supplementation	General daily supplementation; concentrated liquid citrate is also sold as an OTC saline laxative at much higher single doses
Best head-to-head result	Did not outperform citrate in the one trial that compared them	Highest blood magnesium of the forms tested, at both 24 hours and 60 days
Watch out for	Marketed as gentler than citrate, without a trial showing that	The laxative-strength citrate product and a daily supplement capsule are different doses of the same compound

What the head-to-head evidence shows

The most relevant human trial is a 2003 randomized, double-blind, placebo-controlled study that gave 46 healthy adults 300 mg of elemental magnesium a day, as citrate, an amino-acid chelate, or oxide, for 60 days. Citrate produced the greatest rise in blood magnesium both 24 hours after the first dose and after 60 days, and the greatest salivary magnesium after 60 days. The amino-acid chelate did not outperform citrate on any measure, and oxide didn't differ from placebo at all.

A 2024 crossover study in 40 healthy adults measured plasma magnesium after single doses of citrate, oxide, and magnesium bisglycinate. Magnesium levels rose significantly after citrate and after oxide; they did not rise significantly after bisglycinate at any timepoint. That study was funded by a competing magnesium-ingredient maker, which is a real reason to discount its size, but the direction of the result — citrate performing at least as well as glycinate — lines up with the 2003 trial.

A 2017 review of the broader absorption literature concludes that the type of magnesium salt matters less than is commonly assumed, and that where organic forms outperform inorganic ones, the effect isn't consistent across studies. Nothing in that literature shows glycinate outperforming citrate.

What each is typically used for

Both are sold as general-purpose daily magnesium supplements. Citrate has a second, separate use: concentrated liquid magnesium citrate (like the bottles sold for bowel prep before a colonoscopy) is an over-the-counter saline laxative at a dose far higher than a daily supplement capsule. That's a different product used for a different purpose — it doesn't mean a citrate supplement capsule works as a laxative at typical daily doses, though loose stools are the most common side effect of any magnesium form taken above what the gut can absorb.

Glycinate doesn't have that secondary drug use. It's marketed mainly on two claims — sleep support and being gentler on the stomach than citrate — and neither is well supported. We cover the sleep literature in full in magnesium glycinate and sleep: what the evidence actually shows. For how glycinate compares with other common forms, see types of magnesium compared and magnesium glycinate vs oxide. For the basics of the form itself, see what is magnesium glycinate?

Side effects

Both forms share magnesium's most common side effect: loose stools or diarrhea at higher intakes, more likely above the 350 mg/day supplemental upper limit. Citrate is generally considered more likely to loosen stools than glycinate at an equivalent elemental dose, which is consistent with its laxative-strength product existing at all — but there's no controlled trial directly comparing GI tolerability between citrate and glycinate capsules at matched everyday doses, so treat that as a reasonable inference rather than a demonstrated result.

Questions people ask

What is the difference between magnesium glycinate and magnesium citrate?

Citrate is magnesium bound to citric acid; glycinate is magnesium bound to the amino acid glycine. Citrate carries more elemental magnesium per gram (~16% vs ~11–14%) and has outperformed glycinate in the one direct human comparison. Both cover the same basic nutrient roles.

Which is better, magnesium glycinate or magnesium citrate?

On absorption evidence, citrate has the edge: it produced the highest blood magnesium in the 2003 head-to-head trial, and a 2024 study found no significant plasma rise from bisglycinate at all. If citrate's laxative effect is a problem for you personally, glycinate is a reasonable lower-effect alternative, but that's a practical trade-off, not a proven advantage.

Can you take magnesium glycinate and magnesium citrate together?

There's no specific reason not to, but there's also no reason to: both simply supply elemental magnesium, and taking two forms just means adding their elemental amounts together against the same 350 mg/day supplemental upper limit. Combining them doesn't add a benefit beyond taking either one at the equivalent total dose.

Is magnesium glycinate the same as magnesium citrate?

No. They're different compounds with different elemental percentages, and the one trial that tested them side by side found citrate absorbed better, not the same.

Is magnesium glycinate or citrate better for someone who gets loose stools easily?

Glycinate is generally marketed as the gentler choice for that reason, and it's a plausible one given citrate's separate use as a laxative at higher doses. There isn't a controlled trial proving the difference at matched daily doses, so this is a reasonable thing to try, not an established fact.