Magnesium glycinate vs citrate: what's actually different (and what it costs)

"Glycinate or citrate?" is one of the most common magnesium questions online. The honest answer is less exciting than most charts suggest. Both are well-absorbed forms. The real differences are how much of each pill is magnesium, how many capsules a serving takes, what your stomach tolerates, and price.

The short answer

In human absorption studies, forms that dissolve well, including citrate and amino-acid chelates such as glycinate, were absorbed better than magnesium oxide. Neither form has been shown in a head-to-head trial to be "the best". NIH lists citrate among the forms that "tend to have higher bioavailability than magnesium oxide and magnesium sulfate". So the choice usually comes down to practical things: tolerance, capsule count and cost per 100 mg of real magnesium.

Glycinate vs citrate at a glance

Percentages are calculated from chemical formulas. Real products vary with water content. Prices: brand store price, checked 21 Oct 2026, before shipping, tax or coupons.

What the absorption studies found

The study most often cited is Walker and colleagues (2003). 46 healthy adults took an amino-acid chelate, citrate, oxide or a placebo for 60 days. The chelate and citrate were absorbed better than oxide. Citrate gave the highest blood levels, and oxide was no different from placebo. An earlier study by Firoz and Graber (2001) measured four commercial products in urine. It found oxide was only about 4% absorbed, while chloride, lactate and aspartate did better.

Keep these studies in proportion. They were small, used different products and amounts, and measured blood or urine levels, not health outcomes. They support "citrate and glycinate are both better absorbed than oxide". They don't support "glycinate is for sleep, citrate is for digestion" as a rule.

"Glycinate is gentler": is it true?

Partly, and mostly from user experience. Citrate and oxide loosen stools for many people, and oxide works as a laxative in a randomized trial. We found no head-to-head trial showing that glycinate causes less diarrhea than citrate at the same amount of magnesium.

The catch with glycinate: bulk and blends

Because bisglycinate is only about 14% magnesium, the powder is heavy for the magnesium it carries. That's why many glycinate products need 2 to 4 capsules per labelled serving. It also explains why some "glycinate" products are blended with cheaper magnesium oxide, which is about 60% magnesium. That's legal if it's listed, and some brands list it openly. BulkSupplements, for example, labels its glycinate as "Magnesium (as Magnesium Glycinate and Magnesium Oxide)".

A quick check: look at the words in brackets after "Magnesium" on the Supplement Facts panel. If oxide is named, it's a blend. If the label also gives a compound weight, divide magnesium mg by compound mg. Pure bisglycinate comes out around 14%, and a lysinate glycinate chelate around 10%. A "glycinate" at 25% or more probably contains something else. Our label math guide walks through the arithmetic with real labels.

What they cost

Comparing bottle prices is misleading, because bottles hold different amounts of magnesium. Cost per 100 mg of actual magnesium is fairer. These are the glycinate and citrate capsules and tablets from our 30-product table:

Every price: brand store price, checked 21 Oct 2026. $ per 100 mg = price ÷ (servings × mg magnesium per serving) × 100. Serving sizes are as printed on labels and are not a suggestion to take that amount.

Budget citrate and budget glycinate with complete labels land in a similar range, roughly 8 to 18 cents per 100 mg. Premium glycinate costs 2 to 4 times that. Momentous and Thorne were listed in the NSF Certified for Sport directory when we checked, which is one thing the higher price buys. See magnesium cost per dose compared for all forms. For a bottle of your own, use the magnesium cost per 100 mg calculator.

How to choose, without a dosing chart

• Check the brackets for oxide if you're paying glycinate prices.
• Count capsules per serving. A cheap bottle that needs 4 capsules may suit you less than one that needs 2.
• Compare cost per 100 mg, not cost per bottle.
• Ask your pharmacist about amounts and timing, especially if you take other medicines.

Related: How much elemental magnesium is in your supplement? · Magnesium cost per dose compared · The Magnesium Decoder · Does magnesium help you sleep? · All guides

More in this series: buffered glycinate check · threonate: what the price buys · premium vs budget · why oxide is cheapest per mg · shopping by the numbers

Sources: NIH Office of Dietary Supplements, Magnesium fact sheet for health professionals; Walker et al. 2003 (Magnesium Research); Firoz & Graber 2001 (Magnesium Research); brand web stores and the NIH Dietary Supplement Label Database, checked 21 Oct 2026. No brand paid to appear, and there are no affiliate links on this page.

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Last updated 30 Oct 2026