Best Magnesium Glycinate 2026: Dose, Verification, Cost

By Erin Rose · Published September 19, 2026 · Reviewed against primary sources · Methodology · About Us

Not medical advice. This summarizes absorption trials, the labels manufacturers file with the NIH, and Amazon prices as of the date shown below. Talk to a clinician before starting magnesium, especially with kidney disease; it can interact with some antibiotics and bisphosphonates.

Only buying on price? The same 10 products ranked purely by cost per 200 mg: cheapest magnesium glycinate →

The three rules that decide a magnesium glycinate

1. Dose by the Supplement Facts row, and want at least 100 mg of it per capsule. The row that says “Magnesium” is elemental magnesium. A front label that says “magnesium bisglycinate 2,000 mg” is quoting the whole compound, of which about 14% is magnesium. The census below found the median glycinate capsule holds 111 mg, so the typical bottle needs 4 capsules for a 400 mg serving. A capsule under 100 mg means four or more pills for a 400 mg serving. Of the 7 capsules and tablets we track, 1 fails this test: Nutricost Magnesium Glycinate 210 mg (70 mg per capsule).

2. Prefer a label someone else has checked. In the one head-to-head of US commercial magnesium products, magnesium oxide was about 4% absorbed while the chloride, lactate and aspartate salts were significantly higher and equivalent to one another (Firoz 2001, PMID 11794633), and a 2021 systematic review of bioavailability studies found the organic forms consistently ahead of oxide but the product-to-product variation wide (Pardo 2021, PMID 34111673). What the capsule actually contains matters, and a USP or NSF mark on the label is a claim that a third party tested it. We checked the public registries: Nature Made Magnesium Glycinate (USP Verified) and Thorne Magnesium Glycinate (NSF/ANSI 173) are confirmed there. For any other product, the listing says one thing and we did not find it in a public registry. 2 of the 6 products passing rule 1 show a mark on the listing: Nature Made Magnesium Glycinate 200mg (USP Verified) and Thorne Magnesium Glycinate (NSF/ANSI 173). A GMP or Non-GMO mark is a factory or sourcing audit, not a test of the finished product, so it does not count here.

3. Then the lowest cost per 200 mg. Across the 10 products the spread is 4.1× for the same form, from $0.117 to $0.481 per 200 mg. Over a year at one 200 mg dose a day that is $42.63 against $175.74. Price decides only after the first two rules, which is why the cheapest product on the shelf is not the best one below.

Every magnesium glycinate we track, ranked

Doses are the elemental magnesium on each product’s Supplement Facts panel; prices are the Amazon price we last recorded for the exact container (see the date below). Cost per 200 mg is price divided by total elemental magnesium in the container, times 200. The “per capsule” column decides rule 1; the “mark” column decides rule 2.

Only one product here puts 400 mg in a single label serving: Vitamin Shoppe Magnesium Glycinate 400 mg, 3 tablets (133 mg a tablet), $0.222 per 200 mg, no third-party mark stated. A full serving is above the 350 mg supplemental limit, so ask your clinician first.

Two powders sit at the cheap end because a scoop carries no capsule cost: BulkSupplements Magnesium Glycinate Powder at $0.117 per 200 mg is 1.7× cheaper than the best-overall pick. The trade is measuring a dose by the half-teaspoon and a strongly bitter taste. Nutricost Magnesium Glycinate 210 mg is the cheapest capsule per 200 mg but carries 70 mg per capsule, so a 400 mg dose is 6 capsules, which is why it fails rule 1 and is not a pick.

Which magnesium glycinate to buy

Product links go to Amazon and we may earn a commission if you buy. It never changes which product we pick or what we say about it. How we choose.

Best overall

Nature Made Magnesium Glycinate 200mg $0.19 per 200 mg

200 mg of elemental magnesium in one capsule, 60 capsules, USP Verified, confirmed in the public registry. The only glycinate we track that passes all three rules: a whole 200 mg dose per capsule, a product-verification mark on the label, and the lowest price among the marked products. Two capsules is 400 mg, which is above the 350 mg supplemental limit for adults.

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Practitioner brand, NSF/ANSI 173 listed

Thorne Magnesium Glycinate $0.48 per 200 mg

120 mg per capsule as magnesium glycinate, 90 capsules, NSF/ANSI 173 (NSF's general supplement standard), confirmed in the public registry. It is not in NSF Certified for Sport. It costs 2.5× as much as Nature Made Magnesium Glycinate 200mg per 200 mg, and 400 mg takes about 3.3 capsules.

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Best powder

BulkSupplements Magnesium Glycinate Powder $0.117 per 200 mg

300 mg of elemental magnesium per 2.2 g powder (3/4 tsp), 114 servings, the lowest cost per 200 mg on the page. For someone who dislikes capsules or wants to set an exact dose. It is bitter, and a level measure matters: the dose scales with the scoop, not a pill count.

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We read 149 magnesium glycinate labels: the capsule and the front label disagree

Original research827 magnesium labels retrieved from the NIH Dietary Supplement Label Database; 149 list a glycinate or bisglycinate form in the magnesium row and 57 of those carry the word in the product name. Elemental magnesium per serving and per unit were read from the Supplement Facts panel. Every figure was recomputed in both halves of the read order in each population; 8 of 10 held among the 149 and 5 of 10 among the 57, and a figure is printed only from a population in which it held.

The median product directs 250 mg of elemental magnesium per serving, but the median capsule holds 111 mg, because 78.5% of products define a serving as two or more capsules. 78.5% of labels reach 200 mg per serving and 32.9% reach 400 mg; at the median capsule, 400 mg is 4 capsules. And “glycinate” on the front is not a guarantee of glycinate inside: among the 57 labels named glycinate, 19.3% list another magnesium form in the same row, most often oxide, the least absorbed form, which raises the milligram number, though oxide is poorly absorbed.

Glycinate against the other forms: what the trials measured

The case for glycinate is tolerance, not a large absorption edge. Firoz and Graber gave healthy volunteers four commercial products and measured urinary magnesium: oxide was about 4% absorbed, while the chloride, lactate and aspartate salts were significantly higher and equivalent to one another (Firoz 2001, PMID 11794633). Walker’s randomized trial found citrate more bioavailable than oxide and slightly ahead of amino-acid chelate on some measures (Walker 2003, PMID 14596323), and the 2021 systematic review reads the whole literature the same way: organic salts and chelates ahead of oxide, differences among the organic forms small and study-dependent (Pardo 2021, PMID 34111673). In patients with a shortened bowel, where absorption is hardest, diglycinate outperformed oxide (Schuette 1994, PMID 7815675).

Where glycinate separates is the gut. Citrate and oxide pull water into the bowel, which is why citrate is sold as a laxative at gram doses and why 400 mg of either loosens stools in a meaningful share of people. Glycinate, bound to an amino acid, is often reported as gentler, though no trial has compared forms at the same dose. The full comparison is at glycinate vs citrate and eight forms compared.

Dose and timing

The RDA is 310 to 320 mg a day for women and 400 to 420 mg for men, counting food. The NIH sets the tolerable upper intake for supplemental magnesium at 350 mg a day for adults, the point above which diarrhea becomes common; food magnesium does not count against it. Some people who supplement take 100 to 200 mg to fill the gap between diet and the RDA; ask your clinician what suits you, and check the serving size, since many labels direct two capsules. The dosage guide walks through the arithmetic by diet and by goal.

In sleep research, trials used 320 to 500 mg of elemental magnesium in the evening, which is above the 350 mg supplemental limit for adults. A meta-analysis of three randomized trials in older adults reported a small change in sleep onset on low-quality evidence (Mah 2021, PMID 33865376); the glycine in glycinate has its own small record, studied at 3 g before bed for subjective sleep quality in a small Japanese crossover study (Bannai 2012, PMID 22293292), though a 200 mg magnesium capsule carries only about 1.2 g of glycine. Magnesium can interfere with quinolone and tetracycline antibiotics and with bisphosphonates, so ask your pharmacist about timing. Thiazide diuretics are associated with lower magnesium (Kieboom 2018, PMID 30095199). See best time to take magnesium and side effects by form.

Frequently asked questions

Related guides

• Magnesium: forms, dose and what to buy
• Cheapest magnesium glycinate: cost per 200 mg, ranked
• Magnesium glycinate vs citrate
• Thorne vs Doctor’s Best glycinate
• Magnesium and sleep
• Magnesium dosage guide
• Best magnesium supplement, all forms

Sources