Which form is best for sleep?

Glycinate first (the glycine co-factor itself has mild sleep effects per Yamadera 2007), threonate second if you want the cognitive overlap. Citrate can work but the GI effect often disturbs sleep in the opposite direction. Dose 200-400 mg elemental Mg, 60-90 minutes before bed. Evidence is modest (Abbasi 2012, small trial) but the downside is minimal.

Do I need magnesium if I eat a varied diet?

Maybe. NHANES data shows ~50% of US adults below the EAR for magnesium (Rosanoff 2012). Pumpkin seeds, spinach, almonds, and dark chocolate are the dense food sources. If your diet includes daily nuts, leafy greens, or legumes, supplementation is lower-priority. If it doesn't, 200-300 mg elemental Mg/day is defensible.

Why does the label show more mg than the elemental magnesium?

'Magnesium glycinate 1000 mg' refers to the compound weight, not the magnesium content. Glycinate is ~14% elemental Mg by mass, so 1000 mg glycinate delivers ~140 mg actual magnesium. Always check the 'elemental magnesium' line on the supplement facts panel. Brands that only list compound weight are obscuring dose.

Can I take magnesium with calcium?

Yes, and the 2:1 calcium-to-magnesium balance is the public-health target (NIH ODS). At supplemental doses, separating them by a couple hours avoids any absorption competition, though the effect is small. More important: don't supplement calcium if you're already getting it from dairy and greens.

What's the upper limit before GI effects?

The UL from NIH ODS is 350 mg/day from supplements (not food). Most people tolerate 400-600 mg/day of glycinate. Citrate and oxide hit the laxative threshold around 300-400 mg. Threonate is usually tolerated up to the dosed 2 g (144 mg elemental) with minimal GI effect.

Is magnesium threonate worth the premium?

Only for the specific use case. The CNS-penetration claim rests on preclinical rodent work (Slutsky 2010) and a small human cognitive-aging RCT (Liu 2016). It doesn't beat glycinate for general sufficiency. Pay 4-5x the glycinate price only if cognition or sleep is your primary target and you've already ruled out glycinate.

Comparison · ranked· Supplements

Best magnesium forms, compared

Evidence reviewed·05 sources cited·Dr. Soraya Khan, RDN

Tier B evidence

Which magnesium form for which use case, absorption data, dose ranges, and brand recommendations.

Vol. 1Issue 042026-04-21larderlab.com

Educational use only. Larderlab content is educational. Pantry, macro, and supplement guidance is not a substitute for medical advice. Consult a registered dietitian or your physician before making material changes to your diet or supplementation.

DisclosureLarderlab tests and recommends products independently. We sometimes earn a commission when you buy through our links, rankings are decided before the affiliate relationship is checked, not after.

§ 1 · Editor's pick, Best default (glycinate)

Confidence: High

Thorne Magnesium Bisglycinate

NSF Certified for Sport, 200 mg elemental magnesium per serving as bisglycinate (Albion-chelated). Glycinate is the broadest-use form, better tolerated than citrate, better absorbed than oxide. ~$0.30/serving (priced April 2026) beats pharmacy-grade alternatives. BulkSupplements magnesium glycinate powder is the budget swap if you tolerate unflavored powder.

Check price · ThorneAffiliate link · funds the dose testing

§ 2 · Systems table

Every product, ranked.

9 rows · click to sort

Systems tableDefault sort: rank (editorial). Click any column header to re-sort.

9 rows · click a ▲ header to sort

#				Notes	Confidence
01	Thorne Magnesium Bisglycinate	Best glycinate (default)	01	NSF Certified for Sport, Albion-chelated bisglycinate, 200 mg elemental Mg per serving. The default recommendation for most readers: good absorption, minimal GI impact, no laxative effect at 200-400 mg doses.	High
02	Pure Encapsulations Magnesium Glycinate	Clinician-grade glycinate	02	Hypoallergenic line, 120 mg elemental Mg per capsule. NSF-audited facility. The pick if a functional-medicine practitioner is specifying brand. Higher $/mg than Thorne, equivalent efficacy.	High
03	BulkSupplements Magnesium Glycinate Powder	Best $/g glycinate	03	Unflavored powder, COA published. ~$0.05/serving at 200 mg elemental Mg. 4-6x cheaper than capsule brands; trade the tablet convenience for unit cost.	High
04	Doctor's Best High Absorption Magnesium (TRAACS)	Albion-chelated budget retail	04	TRAACS-branded Albion chelate, 100 mg elemental Mg per tablet. Wide retail availability, ~$0.10/serving. A step down from Thorne on testing stringency; good mid-market pick.	Medium
05	Momentous Magnesium L-Threonate	Best threonate (cognitive / sleep)	05	Magtein-licensed L-threonate form, dosed at 2 g providing ~144 mg elemental Mg. Only form with demonstrated CNS penetration in preclinical work (Slutsky 2010). Use case is narrow: cognitive support or sleep quality. Not a replacement for a general magnesium-sufficiency dose.	Medium
06	Life Extension Neuro-Mag (Magtein)	Threonate alternative	06	Same Magtein raw material as Momentous, different capsule format. ~$0.35/serving. Equivalent mechanism; choose on price at purchase date.	Medium
07	Natural Vitality CALM (Magnesium Citrate)	Best citrate (bowel mobility)	07	Magnesium citrate powder, flavored. Citrate has the best osmotic effect in the gut, the correct pick if constipation is the target endpoint. Not ideal for daily cognitive/sleep use (GI effects at 300+ mg).	Medium
08	Klean Athlete Klean Magnesium	Clinical sport	08	Magnesium glycinate + citrate blend, NSF Certified for Sport. Clinician-facing brand. Equivalent to Thorne on testing; blend format delivers both general-use and mobility effect.	Medium
09	Needed Magnesium Glycinate	Pregnancy-formulated	09	Third-party tested, glycinate form, pregnancy-safe formulation audited. ~$0.40/serving. Pay the premium only if pregnancy/postpartum auditing matters.	Medium

§ 3 · What we'd skip

Named, with the reason.

Kirkland Signature Magnesium (oxide)

Skip (low absorption)

Magnesium oxide, ~4% absorbed (Firoz 2001). Bulk retailer cheap but 25x more pills needed than a glycinate to deliver equivalent absorbed dose. The $/g math only works if you're hitting a bowel-mobility use case; otherwise skip.

Any magnesium aspartate or glutamate

Skip (amino profile concerns)

Aspartate and glutamate are excitatory amino acids. No evidence of harm at supplemental doses, but no advantage over glycinate either. Stick with glycinate as the default chelate.

Methodology

§ 4 / spec

How this was specified

01Inputs measured: Retail price (dated) · label claim · Certificate of Analysis · third-party test (Informed Sport / NSF / ConsumerLab / Clean Label) · leucine per serving from COA, not marketing.
02Protocols tested: Per-kg target from four literature ranges (IOM RDA, Phillips 2017, Morton 2018, ISSN). Brands scored against Moore 2015 leucine-per-dose threshold (~0.4 g/kg).
03Cost-basis verified: $/gram of protein and $/gram of leucine at warehouse pricing (Costco), mail-order (Amazon), and DTC retail. Re-checked quarterly, flagged when drift exceeds 15%.
04Confidence level: High on ranked order. Medium on absolute $/g (prices drift). Low on serving-size claims where COA is older than 18 months, flagged [VERIFY].

§ 5 · Questions

What people ask us most.

Which form is best for sleep?: Glycinate first (the glycine co-factor itself has mild sleep effects per Yamadera 2007), threonate second if you want the cognitive overlap. Citrate can work but the GI effect often disturbs sleep in the opposite direction. Dose 200-400 mg elemental Mg, 60-90 minutes before bed. Evidence is modest (Abbasi 2012, small trial) but the downside is minimal.
Do I need magnesium if I eat a varied diet?: Maybe. NHANES data shows ~50% of US adults below the EAR for magnesium (Rosanoff 2012). Pumpkin seeds, spinach, almonds, and dark chocolate are the dense food sources. If your diet includes daily nuts, leafy greens, or legumes, supplementation is lower-priority. If it doesn't, 200-300 mg elemental Mg/day is defensible.
Why does the label show more mg than the elemental magnesium?: 'Magnesium glycinate 1000 mg' refers to the compound weight, not the magnesium content. Glycinate is ~14% elemental Mg by mass, so 1000 mg glycinate delivers ~140 mg actual magnesium. Always check the 'elemental magnesium' line on the supplement facts panel. Brands that only list compound weight are obscuring dose.
Can I take magnesium with calcium?: Yes, and the 2:1 calcium-to-magnesium balance is the public-health target (NIH ODS). At supplemental doses, separating them by a couple hours avoids any absorption competition, though the effect is small. More important: don't supplement calcium if you're already getting it from dairy and greens.
What's the upper limit before GI effects?: The UL from NIH ODS is 350 mg/day from supplements (not food). Most people tolerate 400-600 mg/day of glycinate. Citrate and oxide hit the laxative threshold around 300-400 mg. Threonate is usually tolerated up to the dosed 2 g (144 mg elemental) with minimal GI effect.
Is magnesium threonate worth the premium?: Only for the specific use case. The CNS-penetration claim rests on preclinical rodent work (Slutsky 2010) and a small human cognitive-aging RCT (Liu 2016). It doesn't beat glycinate for general sufficiency. Pay 4-5x the glycinate price only if cognition or sleep is your primary target and you've already ruled out glycinate.

What would change our mind

A published Certificate of Analysis from a ranked brand that contradicts the label claim we scored against. An independent lab result (Clean Label, ConsumerLab) finding heavy-metal or amino-spiking failures on a current top pick. A peer-reviewed meta-analysis that shifts the leucine-per-dose threshold. Any of those triggers a dated revision within a week.

Sources

Every claim, cited.

05 refs

The Larderlab Team · byline

The Larderlab Team builds evidence-led frameworks for eating, lifting, and stocking a kitchen. We cite every claim. We publish the spreadsheet when possible. We buy what we review at retail price. When new data lands, we revise with a dated note.

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