Written by Dr Ilma Imtiaz

Quick answer: Magnesium L-threonate and magnesium glycinate both provide magnesium, an essential mineral needed for normal brain and nervous system function. L-threonate currently has more research specifically focused on cognitive performance, while glycinate is a well-tolerated chelated form used for broader magnesium supplementation, with some emerging cognitive research of its own. No human study has directly compared magnesium L-threonate with magnesium glycinate for cognitive outcomes, so the evidence does not establish one as universally better.

Key Points

• Magnesium supports normal brain and nervous-system function, including nerve signalling and cellular energy production [1].

• Magnesium L-threonate has been studied more directly for cognitive performance, including working memory, episodic memory and reaction time [2-4].

• Magnesium supplementation has also shown an interesting cognitive signal in older adults in a randomized trial using magnesium glycinate [5].

• Animal research found that magnesium L-threonate increased brain magnesium, but this has not been directly demonstrated in the human brain [2].

• There are currently no head-to-head human trials comparing magnesium L-threonate and magnesium glycinate for cognitive outcomes.

• For everyday supplementation, elemental magnesium, formulation, tolerability and your overall magnesium needs also matter.

Why Does Magnesium Matter for the Brain?

Magnesium is probably better known for muscles and sleep than for the brain, but the nervous system relies on it too. Magnesium is an essential mineral involved in hundreds of enzyme-dependent reactions throughout the body. It contributes to cellular energy production, normal nerve transmission and the movement of ions such as calcium and potassium across cell membranes [1].

It also interacts with NMDA receptors, which are involved in communication between nerve cells and synaptic plasticity, the ability of connections between neurons to adapt in response to activity [1,2]. These processes are important to normal learning and memory. This helps explain why magnesium has attracted increasing attention in cognitive research. But when choosing a supplement, another question often comes up: does the form of magnesium matter? Two forms frequently compared for this purpose are magnesium L-threonate and magnesium glycinate.

What Is Magnesium L-Threonate?

Magnesium L-threonate is a relatively new form of magnesium that was developed by researchers investigating ways to increase magnesium levels in the brain. It combines magnesium with L-threonic acid, a metabolite of vitamin C. Early animal research found that magnesium L-threonate increased brain magnesium concentrations and was associated with changes in synaptic plasticity, learning and memory [2].

These findings sparked interest in L-threonate as a magnesium form specifically for cognitive research. The increase in brain magnesium has so far been demonstrated in animal research. Human trials have instead investigated whether supplementation translates into measurable changes in memory, reaction time and cognitive performance [3,4].

What Does Human Research on Magnesium L-Threonate Show?

Human research is still developing, but several randomized trials have investigated magnesium L-threonate or L-threonate-containing formulations.

• A Recent Trial Looked Directly at Cognitive Performance

A randomized, double-blind, placebo-controlled trial studied 100 adults aged 18–45 years who reported dissatisfaction with their sleep. Participants received either placebo or 2 g of magnesium L-threonate daily for six weeks [3]. Compared with placebo, those taking magnesium L-threonate showed greater improvements in overall cognitive performance, working memory, episodic memory and reaction time.

Improvements in reaction time and hand-eye coordination are particularly interesting because they bring the findings into everyday life, how quickly we process information and respond to what is happening around us. The takeaway? After six weeks, magnesium L-threonate showed promising effects on several aspects of memory and mental performance in this group of adults.

• Another Trial: Memory and Attention

Another double-blind, placebo-controlled trial studied 109 healthy adults aged 18–65 years over 30 days [4]. Participants taking the study formula showed improvements across several measures of memory, including visual recognition, visual working memory, attention and overall memory performance compared with placebo [4]. Improvements were particularly notable among older participants. For someone reading this in practical terms, these findings suggest potential benefits for the kinds of cognitive skills used to take in information, hold it in mind and recall it when needed. The study did use a multi-ingredient formula containing magnesium L-threonate, phosphatidylserine and vitamins C and D, so the findings reflect the combination rather than magnesium L-threonate alone. Even so, alongside the more recent L-threonate trial, it adds to the emerging human research examining magnesium L-threonate-containing supplements and cognitive performance [3,4].

An interesting finding: In another randomized trial, adults taking magnesium L-threonate for three weeks reported improvements in mental alertness, daytime energy and productivity, alongside changes in several sleep-related measures [8].

What Is Magnesium Glycinate?

Magnesium glycinate, also commonly called magnesium bisglycinate, is magnesium chelated with the amino acid glycine. Glycine may also contribute to magnesium glycinate's calming profile. It plays a role in nervous-system signalling and has been studied for its effects on sleep and the body's natural nighttime drop in temperature [2].

Magnesium glycinate has a different research history from L-threonate. Rather than being developed specifically around increasing brain magnesium, glycinate is widely used as a supplemental form because it is well absorbed and generally gentle on the digestive system. Because magnesium is bound to glycine, it can be absorbed through amino acid pathways in the gut and is less likely to have the laxative effect associated with some other forms of magnesium.

This gives magnesium glycinate a broader role in providing magnesium needed for normal muscle function, nerve signalling, energy metabolism, protein synthesis and bone structure [1]. More recently, research has also explored its potential role in cognitive function.

What Does the Research Show for Magnesium Glycinate and Cognitive Function?

One randomized controlled trial examined magnesium supplementation and cognitive function in adults aged 40–85 years [5]. Participants received personalized magnesium supplementation using magnesium glycinate, with the dose calculated according to their dietary calcium-to-magnesium intake ratio. The average supplemental magnesium dose was approximately 216 mg per day.

Across the study population as a whole, cognitive scores were similar between the magnesium and placebo groups. However, researchers found an interesting result among participants older than 65 years with a relatively high calcium-to-magnesium intake ratio at baseline. In this group, cognitive function improved by 9.1% following magnesium supplementation, according to the study's cognitive assessment. This suggests that age and nutritional status may be important when considering how people respond to magnesium supplementation. It also adds promising human evidence for magnesium glycinate and cognitive function, particularly in older adults.

Magnesium Threonate vs. Glycinate: How Do They Compare?

The biggest difference is not simply that one form is “for the brain” and the other is not. Both ultimately provide magnesium. What differs is how the forms have been studied.

Does Magnesium L-Threonate Cross the Blood-Brain Barrier?

This is one of the main reasons L-threonate is marketed for brain health. The original animal research found that oral magnesium L-threonate increased brain magnesium concentrations in rats [2]. Human studies have since reported changes in certain cognitive outcomes following supplementation [3,4]. However, human trials have not directly demonstrated that magnesium L-threonate increases brain magnesium more effectively than magnesium glycinate. So, the current evidence gives L-threonate an interesting brain-focused research rationale, but it does not establish that it delivers more magnesium to the human brain than glycinate.

Where Does Magnesium Glycinate Fit?

Magnesium glycinate has a broader role as an everyday magnesium supplement. Magnesium contributes to normal nerve and muscle function, energy metabolism, protein synthesis and bone structure [1]. Glycinate provides this essential mineral in a chelated form.

There is also emerging research in areas connected with everyday nervous-system function.

For example, a 2025 randomized, double-blind, placebo-controlled trial studied 155 adults aged 18–65 years with self-reported poor sleep [7]. Participants received either placebo or 250 mg of elemental magnesium as magnesium bisglycinate daily for four weeks.

Sleep scores improved modestly but significantly compared with placebo.

Combined with the cognitive findings reported in older adults [5], this gives magnesium glycinate a broader evidence story: a practical form for supporting magnesium intake and normal nervous-system function, with emerging research examining sleep and cognition.

So, Which Magnesium Is Better for Brain Health?

Magnesium may be better known for muscles and sleep than for the brain, but the nervous system relies on it too. And magnesium intake is surprisingly easy to fall short on: around 48% of Americans consume less magnesium from food and beverages than their estimated requirements [8]. There isn't currently a head-to-head clinical trial that can tell us that one is definitively “better.” If you're comparing the type of research available, magnesium L-threonate has been studied more directly for cognitive performance, including working memory, episodic memory and reaction time [3,4].

Magnesium glycinate has a broader role as a supplemental magnesium form, providing magnesium needed for normal nervous-system and cellular function [1]. It also has some promising cognitive research in older adults, alongside research examining healthy sleep support [5,7]. The practical difference is therefore less about choosing a winner and more about what you want from your magnesium supplement. 

Take Home Message

Magnesium L-threonate and magnesium glycinate both provide magnesium needed for normal brain and nervous-system function, but their research tells slightly different stories. L-threonate has been studied more specifically for cognitive performance, while glycinate is a versatile form for everyday magnesium supplementation with emerging research in cognition.

Rather than one being simply “better,” the difference comes down to what each form has been studied for and what you want from your magnesium supplement.

FAQs

Is magnesium threonate better than glycinate for brain health?

L-threonate currently has more research specifically examining cognitive performance, while glycinate has broader use as a supplemental magnesium form. No human trial has directly compared the two for cognitive outcomes [3-6].

Does magnesium glycinate cross the blood-brain barrier?

Magnesium supports normal brain and nervous-system function. However, human research has not established that magnesium glycinate specifically increases magnesium levels in the brain.

What does the research say about magnesium glycinate and ADHD?

Magnesium plays an important role in normal neurological function, but there is currently insufficient evidence for magnesium glycinate specifically in ADHD. Most research has examined magnesium status or other magnesium interventions rather than magnesium glycinate.

What is magnesium glycinate lysinate good for, and is it different from magnesium L-threonate?

Magnesium glycinate lysinate is magnesium chelated with the amino acids glycine and lysine and is used as a supplemental source of magnesium. Magnesium L-threonate is a different compound, formed with L-threonic acid, and has been studied specifically for cognitive outcomes.

Does magnesium glycinate support brain health?

Magnesium contributes to normal nerve signalling, cellular energy production and other processes required for normal brain and nervous-system function [1]. Magnesium glycinate provides magnesium in a chelated supplemental form.

Does magnesium L-threonate increase magnesium in the brain?

Animal research found that magnesium L-threonate increased brain magnesium concentrations [2]. Human studies have examined cognitive outcomes, but direct evidence showing increased magnesium concentrations in the human brain is not currently available [3,6].

Can magnesium glycinate support healthy sleep?

Magnesium bisglycinate has been studied for healthy sleep support. In a 2025 randomized trial, 250 mg of elemental magnesium daily for four weeks produced a modest improvement in a sleep-related outcome compared with placebo [7].

References

1. Jahnen-Dechent W, Ketteler M. Magnesium basics. Clin Kidney J. 2012;5(suppl 1):i3-i14. https://doi.org/10.1093/ndtplus/sfr163

2. Slutsky I, Abumaria N, Wu LJ, et al. Enhancement of learning and memory by elevating brain magnesium. Neuron. 2010;65(2):165-177. https://doi.org/10.1016/j.neuron.2009.12.026

3. Lopresti AL, Smith SJ. The effects of magnesium L-threonate (Magtein®) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial. Front Nutr. 2025;12:1729164. https://doi.org/10.3389/fnut.2025.1729164

4. Zhang C, Hu Q, Li S, et al. A Magtein®, magnesium L-threonate, -based formula improves brain cognitive functions in healthy Chinese adults. Nutrients. 2022;14(24):5235. https://doi.org/10.3390/nu14245235

5. Zhu X, Borenstein AR, Zheng Y, et al. Ca:Mg ratio, APOE cytosine modifications, and cognitive function: results from a randomized trial. J Alzheimers Dis. 2020;75(1):85-98. https://doi.org/10.3233/JAD-191223

6. Chen F, Wang J, Cheng Y, et al. Magnesium and cognitive health in adults: a systematic review and meta-analysis. Adv Nutr. 2024;15(8):100272. https://doi.org/10.1016/j.advnut.2024.100272

7. Schuster J, Cycelskij I, Lopresti A, Hahn A. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nat Sci Sleep. 2025;17:2027-2040. https://doi.org/10.2147/NSS.S524348

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.