Magnesium: Forms, Dosing, and Why You’re Probably Deficient

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Last Updated: March 2026

Magnesium Supplementation Guide: Forms, Dosing, and Why You’re Probably Deficient (2026)

Magnesium is one of the most discussed supplements in the longevity space, and for good reason. Andrew Huberman has called magnesium threonate and bisglycinate cornerstones of his nightly sleep protocol on the Huberman Lab podcast, taking both forms 30 to 60 minutes before bed. Peter Attia dedicated an entire episode of The Drive (AMA #54) to magnesium, arguing that subclinical deficiency is far more prevalent than most clinicians recognize. Dr. Brad Stanfield, after reviewing 14 studies on his YouTube channel, concluded that magnesium is one of the few supplements with strong enough evidence that virtually everyone should consider it.

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Yet despite this expert consensus, the average person still struggles with two basic questions: which form of magnesium should I take, and how much do I actually need? The supplement aisle offers a dizzying array of options — glycinate, threonate, citrate, oxide, taurate, malate — each with different absorption rates, different target tissues, and different price points. Choosing wrong doesn’t just waste money. It can mean the magnesium never reaches the cells where it’s needed most.

This guide breaks down what the research says and what the experts recommend, so you can build a magnesium protocol that actually works for your goals — whether that’s better sleep, sharper cognition, improved recovery, or simply correcting a deficiency you probably don’t know you have.

Important: This article reports what published research and named experts have publicly shared about magnesium. We are not prescribing supplements or dosages. Consult a qualified healthcare provider before starting or changing any supplement regimen.

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What Magnesium Does in Your Body

Answer capsule: Magnesium is a cofactor in over 300 enzymatic reactions, plays a direct role in ATP energy production, regulates muscle contraction and nerve signaling, supports bone mineral density, and is essential for DNA synthesis and repair. Without adequate magnesium, fundamental cellular processes slow down or malfunction, creating cascading effects throughout the body.

Most people think of magnesium as a simple mineral. It is anything but simple. Peter Attia noted on AMA #54 of The Drive that magnesium participates in more than 80 percent of metabolic functions in the human body. Published research in the journal Nutrients (November 2025) puts that number even higher, identifying magnesium as a cofactor in over 300 enzymatic processes spanning protein synthesis, nerve function, blood sugar regulation, and blood pressure control.

Energy Production (ATP)

Every cell in your body runs on adenosine triphosphate (ATP). What most people do not realize is that ATP must be bound to a magnesium ion to be biologically active. The molecule your mitochondria actually use is Mg-ATP, not ATP alone. This means that when magnesium levels drop, cellular energy production becomes less efficient — even if your mitochondria are otherwise healthy. This is one reason subclinical magnesium deficiency often manifests as fatigue and low energy before any blood test flags a problem.

Muscle Contraction and Nerve Signaling

Magnesium acts as a natural calcium channel blocker in muscle tissue. Calcium triggers muscle contraction; magnesium enables relaxation. When the ratio tips toward too much calcium and too little magnesium, muscles stay in a semi-contracted state, leading to cramps, tension, and restless legs. In nerve cells, magnesium regulates NMDA receptors — the same receptors that Huberman has discussed extensively in the context of learning and memory. Under normal conditions, magnesium sits in the NMDA receptor channel, preventing overactivation. When magnesium is depleted, these receptors can become overexcitable, contributing to anxiety, poor sleep, and neurological symptoms.

Bone Health

Approximately 60 percent of the body’s magnesium is stored in bone tissue. Magnesium influences both osteoblast and osteoclast activity — the cells that build and break down bone, respectively. Research published in the European Journal of Epidemiology has found associations between low magnesium intake and increased fracture risk, particularly in older adults. Attia has discussed this in the context of his broader longevity framework: bone mineral density is one of the key metrics he tracks in his patients, and adequate magnesium is part of the foundation.

Cardiovascular Function

Magnesium helps maintain normal heart rhythm, supports blood vessel relaxation, and modulates blood pressure. A 2016 meta-analysis published in BMC Medicine found that higher magnesium intake was associated with a lower risk of heart failure, stroke, and type 2 diabetes. The research paper “Subclinical Magnesium Deficiency: A Principal Driver of Cardiovascular Disease and a Public Health Crisis,” published in Open Heart (2018), argued that the cardiovascular implications of widespread magnesium deficiency have been systematically underappreciated.

DNA Synthesis and Repair

Magnesium is required for DNA and RNA polymerase activity — the enzymes responsible for copying and repairing your genetic material. In the longevity context, this is particularly relevant: accumulated DNA damage is one of the hallmarks of aging identified by Lopez-Otin and colleagues. Without sufficient magnesium, your body’s ability to maintain genomic integrity is compromised at the most fundamental level.

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The Deficiency Problem Nobody Talks About

Answer capsule: Research suggests that a significant portion of the population in developed countries fails to meet recommended magnesium intake levels. Standard serum blood tests are unreliable because less than one percent of the body’s magnesium circulates in the blood. Symptoms are nonspecific — fatigue, poor sleep, muscle cramps, anxiety — making deficiency easy to miss and even easier to misattribute to other causes.

Peter Attia addressed this problem directly on AMA #54 of The Drive, noting that magnesium depletion in otherwise healthy people is common and that standard blood tests are essentially useless for detecting it. The reason is straightforward: less than one percent of total body magnesium is found in serum. The rest is locked in bones (about 60 percent), muscles (about 27 percent), and soft tissues. A standard metabolic panel can show normal serum magnesium while intracellular levels are critically low.

A December 2025 review published in the International Journal for Vitamin and Nutrition Research estimated that roughly 2.4 billion people worldwide — approximately 31 percent of the global population — fail to meet recommended magnesium intake levels. In the United States specifically, data from National Health and Nutrition Examination Survey (NHANES) cycles have consistently shown that a large percentage of adults do not consume enough magnesium through diet alone.

Why Deficiency Has Become So Common

• Soil depletion: Intensive farming practices have reduced the magnesium content of agricultural soils over decades. Research published in Nutrients (2020) found that the magnesium content of crops has declined meaningfully since the mid-20th century because conventional fertilization protocols typically replenish nitrogen, phosphorus, and potassium but not magnesium. The magnesium content of wheat, for example, has dropped nearly 20 percent since the 1960s.
• Food processing: Published estimates suggest that a large percentage of magnesium can be lost during food processing. Refined grains lose most of their magnesium content when the bran and germ are removed.
• Modern diets: The shift away from whole grains, leafy greens, nuts, and seeds — the primary dietary sources of magnesium — has further reduced intake. Paleolithic societies consumed an estimated 600 mg of magnesium daily, well above today’s average.
• Medications: Proton pump inhibitors (PPIs), common blood pressure medications, and certain antibiotics can deplete magnesium. Given that PPIs are among the most prescribed drug classes globally, this is a significant but often overlooked factor.
• Stress and exercise: Both physical and psychological stress increase magnesium excretion through urine. Athletes and people under chronic stress have higher magnesium requirements.

Symptoms of Subclinical Deficiency

The challenge with subclinical magnesium deficiency is that its symptoms overlap with dozens of other conditions:

• Persistent fatigue despite adequate sleep
• Muscle cramps, twitches, or tension (especially at night)
• Difficulty falling asleep or staying asleep
• Anxiety or irritability without clear cause
• Brain fog or difficulty concentrating
• Headaches or migraines
• Heart palpitations or irregular heartbeat
• Constipation

Because these symptoms are so nonspecific, most clinicians attribute them to stress, aging, or other conditions long before considering magnesium status. Attia has argued on The Drive that this diagnostic blind spot means many patients are treated symptomatically for problems that a simple, inexpensive mineral supplement could address at the root cause.

Better Testing Options

If you want a more accurate picture of your magnesium status, experts suggest looking beyond the standard serum magnesium test:

• RBC magnesium (red blood cell magnesium): Measures magnesium inside red blood cells rather than in serum. This gives a better approximation of intracellular magnesium levels. Target range is typically 5.0–7.0 mg/dL, with some longevity-focused physicians aiming for the upper half of that range.
• Magnesium depletion score: A composite clinical score incorporating dietary intake, medication use, and clinical symptoms. Research published in Frontiers in Endocrinology (2025) used this approach to identify at-risk populations in NHANES data.

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Magnesium Forms Explained: A Complete Comparison

Answer capsule: Not all magnesium supplements are created equal. The form determines how well it is absorbed, where it ends up in the body, and what secondary benefits it provides. Organic chelated forms like glycinate, threonate, and citrate are generally better absorbed than inorganic forms like oxide. Your choice should be guided by your primary goal — sleep, cognition, general deficiency correction, or gut regularity.

This is the section most people get wrong, and it is where the most money gets wasted. The word “magnesium” on a supplement label tells you almost nothing. What matters is the compound — the molecule that magnesium is bound to — because that determines absorption rate, tissue distribution, and secondary effects. A 2019 animal bioavailability study published in Biological Trace Element Research compared five magnesium compounds head-to-head and found dramatic differences in absorption and tissue distribution.

Here is what the research and expert commentary say about each major form:

Form	Absorption	Elemental Mg per Dose	Best Use Case	GI Tolerance	Approximate Cost	Evidence Level
Magnesium Glycinate (Bisglycinate)	High	~14% elemental Mg	Sleep, anxiety, general deficiency	Excellent — very gentle	$$	Strong (multiple RCTs)
Magnesium L-Threonate	High (crosses BBB)	~8% elemental Mg	Cognition, memory, brain health	Good (5% report GI issues)	$$$	Moderate (growing human data)
Magnesium Citrate	High	~11% elemental Mg	General deficiency, constipation	Fair — mild laxative effect	$	Strong (well-studied)
Magnesium Oxide	Low (~4%)	~60% elemental Mg	Bowel regularity, budget option	Poor — significant laxative effect	$	Strong (well-studied, poorly absorbed)
Magnesium Taurate	Good (high brain penetration)	~9% elemental Mg	Cardiovascular health, heart rhythm	Good	$$	Moderate (animal data strong, human data growing)
Magnesium Malate	High (longest serum levels)	~15% elemental Mg	Energy, exercise recovery, muscle pain	Good	$$	Moderate (limited human trials)

Magnesium Glycinate (Bisglycinate)

Magnesium glycinate is magnesium bound to the amino acid glycine. It has two key advantages: high bioavailability via the dipeptide transporter pathway, and the calming effect of glycine itself. Glycine acts as an inhibitory neurotransmitter, which is why this form is particularly favored for sleep and anxiety.

Huberman has recommended magnesium bisglycinate as a core part of his sleep protocol, reporting on the Huberman Lab podcast that he takes 200 mg before bed alongside magnesium threonate. He has noted that bisglycinate is an effective and more affordable alternative for people who cannot find or afford threonate. Dr. Brad Stanfield, after reviewing the evidence, selected magnesium glycinate as the form in his own Sleep supplement, citing a meta-analysis of randomized controlled trials showing that five out of eight included trials reported improvements in at least one aspect of sleep.

This form is also exceptionally well tolerated. Unlike citrate or oxide, glycinate rarely causes loose stools, making it suitable for people who need higher doses or have sensitive digestive systems.

Magnesium L-Threonate

Magnesium L-threonate was developed at MIT and is the only form of magnesium shown in published research to significantly elevate magnesium levels in the brain and cerebrospinal fluid. The landmark 2010 study in Neuron demonstrated that magnesium threonate enhanced synaptic density, learning, and both short-term and long-term memory in animal models by upregulating NR2B-containing NMDA receptors.

Since then, human clinical data has accumulated. A 2022 study in Nutrients found improvements across all five subcategories of the Clinical Memory Test in adults taking a magnesium L-threonate-based formula. A 2025 randomized controlled trial published in Frontiers in Nutrition reported that six weeks of magnesium L-threonate supplementation improved cognitive performance and lowered resting heart rate in young-to-middle-aged adults.

Huberman has specifically discussed magnesium threonate’s mechanism on the Huberman Lab podcast, explaining that it is actively shuttled to the brain where it engages the GABA pathway. He takes 145 mg of elemental magnesium from threonate (roughly 2 grams of the compound) 30 to 60 minutes before bed. Attia also takes magnesium L-threonate nightly, noting on The Drive that it may offer cognitive health benefits due to its ability to cross the blood-brain barrier.

The primary drawback is cost. Magnesium threonate is the most expensive form, and its low elemental magnesium content (roughly 8 percent) means you need a larger quantity to get a meaningful magnesium dose. Dr. Stanfield has expressed skepticism about whether the premium is justified, noting that the human evidence, while promising, includes small, manufacturer-funded studies.

Magnesium Citrate

Magnesium citrate is one of the most widely used and extensively studied forms. It dissolves readily in water, and a small study of 14 participants found it to be among the most bioavailable forms in the digestive tract. It is commonly used for correcting general deficiency and is the go-to recommendation for people who are new to magnesium supplementation.

Peter Attia has mentioned magnesium citrate as one of the forms he recommends to patients who are just starting magnesium supplementation, alongside oxide for bowel regulation. The primary consideration is its mild laxative effect, which can be a feature or a bug depending on your goals. For people with constipation, citrate serves double duty. For others, it may require dose titration to avoid loose stools.

As Stanfield has pointed out, citrate contains only about 11 percent elemental magnesium, so getting a meaningful dose requires a larger quantity of the compound — over 1,100 mg of magnesium citrate to deliver roughly 126 mg of elemental magnesium.

Magnesium Oxide

Magnesium oxide has the highest elemental magnesium content of any form (roughly 60 percent by weight) but the lowest bioavailability (estimated around 4 percent absorption). This seems contradictory, but it explains why oxide remains popular despite being poorly absorbed: you can fit a lot of elemental magnesium into a small pill.

Attia takes up to 500 mg of magnesium oxide before bed specifically for bowel regulation, describing it on The Drive as “arguably the single best tool you can use to regulate bowel function.” He starts patients on 400 mg of magnesium oxide as a baseline, titrating based on bowel response. For people whose primary goal is correcting a systemic magnesium deficiency, however, oxide is a poor choice — most of it passes through the digestive tract unabsorbed.

Stanfield has highlighted a common labeling confusion: a supplement listing 400 mg of magnesium oxide contains roughly 240 mg of elemental magnesium, but because absorption is so low, the actual amount reaching your cells is far less.

Magnesium Taurate

Magnesium taurate combines magnesium with taurine, an amino acid with its own longevity-associated benefits. Animal research published in Biological Trace Element Research found that magnesium acetyl taurate was rapidly absorbed, achieved the second-highest area under the curve, and reached the highest tissue concentration in the brain of any form tested. It was also associated with decreased anxiety indicators in animal models.

Stanfield previously recommended magnesium taurate as his preferred form, specifically because it delivers both magnesium and taurine in a single supplement. He has since shifted to glycinate for his Sleep product but has noted that taurate remains a strong option, particularly for cardiovascular support. Taurine itself has been the subject of significant longevity research, with a June 2023 study in Science finding that taurine deficiency accelerated aging in mice and that supplementation extended lifespan.

Magnesium Malate

Magnesium malate is magnesium bound to malic acid, a compound involved in the Krebs cycle (the cellular energy production pathway). In the same animal bioavailability study that compared five forms, magnesium malate achieved the highest overall area under the curve, and serum levels remained elevated for the longest duration. This makes it theoretically ideal for sustained magnesium delivery.

Malic acid’s role in cellular energy production makes this form popular among people focused on exercise performance and recovery, as well as those dealing with chronic fatigue. However, human clinical data specifically on magnesium malate is more limited compared to glycinate or citrate.

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Magnesium for Sleep

Answer capsule: Magnesium glycinate and magnesium threonate are the two most recommended forms for sleep improvement. Huberman includes both in his nightly sleep protocol, taking them 30 to 60 minutes before bed. The mechanism involves GABA receptor modulation and NMDA receptor regulation, which collectively help quiet neural activity and facilitate the transition to sleep.

Sleep is the single most common reason people reach for magnesium supplements, and it is the area where expert consensus is strongest. On the Huberman Lab podcast Sleep Toolkit episode (#31), Huberman outlined his full sleep supplement protocol. Magnesium threonate is the foundation, followed by apigenin and L-theanine. He also takes magnesium bisglycinate in the evening as a secondary magnesium source.

How Magnesium Improves Sleep

Magnesium supports sleep through multiple pathways:

• GABA activation: Huberman has explained that magnesium threonate is actively transported to the brain where it engages GABA receptors. GABA is the brain’s primary inhibitory neurotransmitter — it is responsible for “turning down” neural activity so you can transition from wakefulness to sleep.
• NMDA receptor regulation: Magnesium blocks NMDA receptors, preventing the excitatory signaling that keeps the brain alert. When magnesium is depleted, NMDA receptors become overactive, contributing to racing thoughts and difficulty shutting down at night.
• Cortisol modulation: Magnesium helps regulate the hypothalamic-pituitary-adrenal (HPA) axis, which controls cortisol release. Lower evening cortisol is critical for sleep onset.
• Muscle relaxation: By counteracting calcium-driven muscle contraction, magnesium reduces the physical tension and restless legs that keep many people awake.

What the Research Shows

A meta-analysis of randomized controlled trials on magnesium supplementation and sleep, which Stanfield cited in his review, found that five of eight included studies reported significant improvements in at least one sleep measure. A 2024 randomized controlled trial published in Sleep Research found that magnesium L-threonate specifically improved sleep quality and daytime functioning in adults with self-reported sleep problems.

Huberman’s Sleep Stack (Magnesium Component)

As described on the Huberman Lab podcast and in his Sleep Toolkit newsletter:

• Magnesium threonate: 145 mg elemental magnesium (from ~2g magnesium threonate), 30–60 minutes before bed
• Magnesium bisglycinate: 200 mg, taken in the evening
• Combined with: Apigenin (50 mg), L-theanine (100–400 mg)

Huberman has recommended starting with magnesium alone for the first week, then adding other sleep supplements one at a time to gauge individual response. He has also noted that roughly 5 percent of people experience gastrointestinal issues with threonate and should switch to bisglycinate exclusively.

For a complete breakdown of Huberman’s sleep protocol including non-supplement strategies, see our Huberman Sleep Protocol 2026 guide.

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Magnesium for Cognitive Function

Answer capsule: Magnesium L-threonate is the standout form for cognitive support because published research demonstrates it can cross the blood-brain barrier and elevate brain magnesium levels. Human clinical trials have shown improvements in memory test scores, and ongoing research is exploring its potential in age-related cognitive decline and neurodegenerative conditions.

The connection between magnesium and brain function centers on the NMDA receptor, which Huberman has described as critical for synaptic plasticity — the brain’s ability to form new connections and encode memories. Under normal conditions, a magnesium ion sits in the NMDA receptor channel, acting as a gatekeeper. When a learning signal is strong enough, the magnesium is displaced, the channel opens, and calcium flows in to trigger the molecular cascade that strengthens synaptic connections. This process, called long-term potentiation (LTP), is the cellular basis of learning and memory.

When brain magnesium levels are low, NMDA receptors lose their gating mechanism. The channels become overactive, responding to noise rather than signal. This leads to both cognitive impairment and the neural excitability associated with anxiety. The challenge is that most forms of supplemental magnesium do not meaningfully raise brain magnesium levels — they are absorbed in the gut and distributed to muscles, bones, and other tissues.

Why Threonate Is Different

Magnesium L-threonate was specifically engineered to solve this problem. Developed by a team at MIT led by Dr. Guosong Liu, the compound uses the threonic acid molecule as a carrier to transport magnesium across the blood-brain barrier. The foundational 2010 study published in Neuron showed that magnesium threonate:

• Increased synaptic density in the hippocampus (the brain’s memory center)
• Enhanced both short-term and long-term memory in animal models
• Upregulated NR2B-containing NMDA receptors, increasing synaptic plasticity
• Increased the number of presynaptic boutons (connection points between neurons)

Human Evidence

The human evidence for magnesium threonate has grown since the initial animal research:

• A 2022 double-blind, placebo-controlled trial published in Nutrients found significant improvements in all five subcategories of the Clinical Memory Test in adults taking a magnesium L-threonate-based formula (Magtein), with older participants showing more pronounced benefits.
• A 2025 randomized controlled trial in Frontiers in Nutrition demonstrated improvements in cognitive performance in young-to-middle-aged adults after just six weeks of supplementation, along with reductions in resting heart rate and improvements in mood.
• Research published in Neural Regeneration Research (2024) explored magnesium L-threonate’s potential in Alzheimer’s disease models, finding that it improved cognition and reduced oxidative stress and inflammation.

Huberman has recommended magnesium threonate specifically for cognitive support on the Huberman Lab podcast, and Attia takes it nightly, noting on The Drive that it may offer cognitive health benefits. However, Stanfield has urged caution about overstating the evidence, pointing out that several key studies were manufacturer-funded and relatively small in scale.

Learn more about how Huberman approaches cognitive supplementation in our complete Huberman Supplement Stack 2026 guide.

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Magnesium for Muscle and Recovery

Answer capsule: Magnesium plays a direct role in muscle contraction and relaxation by regulating calcium transport. A 2024 systematic review found that magnesium supplementation decreased muscle soreness and showed protective effects against muscle damage in physically active individuals. For athletes and regular exercisers, maintaining adequate magnesium status is especially important because exercise increases magnesium excretion.

The relationship between magnesium and muscle function is one of the most physiologically well-established aspects of magnesium science. The calcium transport system that governs muscle contraction depends on intracellular magnesium to function properly. When magnesium is depleted, muscles contract more easily but struggle to fully relax — the classic setup for cramps, spasms, and delayed recovery.

Exercise Performance

A major 2024 systematic review published in the Journal of Translational Medicine examined magnesium supplementation across different types of physical activity and concluded that supplementation decreased muscle soreness, improved performance markers, and showed protective effects against muscle damage. In one study of elite basketball players, 400 mg per day of supplemental magnesium at eight-week intervals improved serum magnesium levels and modulated markers of muscular damage including creatine kinase and lactate dehydrogenase.

Muscle Cramps

The evidence on muscle cramps is more nuanced. While magnesium’s role in muscle relaxation is well established at the cellular level, rigorous clinical trials have produced mixed results:

• A Cochrane Review concluded that magnesium supplementation made little difference in reducing muscle cramp frequency in older adults specifically.
• However, sport-specific research tells a different story. A study on half-marathon runners found that those using a magnesium-rich electrolyte mix experienced significantly fewer exercise-associated muscle cramps compared to those drinking water alone.

The emerging consensus, reflected in the 2024 systematic review, is that magnesium supplementation is most likely to benefit people who are deficient, which — given the prevalence data — includes a large proportion of the physically active population. Athletes lose additional magnesium through sweat and have higher turnover through increased energy metabolism.

Best Forms for Athletes

For muscle and recovery goals, the research points to:

• Magnesium malate: The highest sustained serum levels in bioavailability research, plus malic acid’s involvement in cellular energy production
• Magnesium glycinate: High absorption with minimal GI distress at higher doses
• Magnesium citrate: Well-absorbed and cost-effective, though the laxative effect may be unwanted around training

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What Longevity Experts Recommend

Answer capsule: Leading longevity experts agree that magnesium supplementation is broadly beneficial, but they diverge on preferred forms and dosing strategies. Huberman focuses on threonate and bisglycinate for sleep and cognition. Attia takes a higher total dose combining multiple forms. Stanfield recommends a moderate dose of glycinate and emphasizes diet-first approaches.

Andrew Huberman (Huberman Lab Podcast)

Huberman’s magnesium protocol, as reported across multiple Huberman Lab podcast episodes and his Sleep Toolkit newsletter:

• Magnesium threonate: 145 mg elemental magnesium (~2g compound), taken 30–60 minutes before bed. Primary purpose: sleep quality and cognitive function. He has specifically mentioned the brand Magtein.
• Magnesium bisglycinate: 200 mg, taken in the evening. Primary purpose: additional magnesium intake and muscle relaxation.
• Approach: Huberman has emphasized starting with one supplement at a time and personalizing based on response. He has acknowledged that his stack is tailored to his own blood work and health history.

Peter Attia (The Drive Podcast)

Attia’s magnesium protocol is notably more aggressive, as reported on AMA #54 of The Drive:

• Magnesium L-threonate: Two capsules (~2g of Magtein), taken before sleep. Primary purpose: cognitive health.
• Magnesium oxide: Up to 500 mg before bed. Primary purpose: bowel regulation.
• SlowMag (magnesium chloride): Slow-release form with enteric coating. Primary purpose: systemic magnesium repletion without GI distress.
• Total daily elemental magnesium: Approximately 1 gram across all forms combined.
• Approach: Attia’s position is that magnesium supplementation is safe and broadly recommended, and that patients should titrate oxide dosing based on bowel response.

Dr. Brad Stanfield (YouTube, Dr. Stanfield Website)

Stanfield takes the most conservative approach among the three experts:

• Magnesium glycinate: 126 mg elemental magnesium. He includes this dose in his own Sleep supplement formulation.
• Previous pick: Magnesium taurate, for the dual benefit of magnesium and taurine.
• Approach: Stanfield emphasizes diet first (leafy greens, nuts, seeds, legumes, whole grains) and uses supplementation to fill the gap rather than replace dietary intake. He warns against megadosing and notes that the tolerable upper intake level for supplemental magnesium is 350 mg. He is skeptical of the premium pricing on magnesium threonate given the current state of the human evidence.

For a deeper comparison of how these experts approach supplementation broadly, see our guides on Dr. Stanfield’s Supplement Protocol and What Longevity Experts Agree and Disagree On.

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Optimal Dosing Protocol

Answer capsule: Most experts recommend 200 to 400 mg of elemental magnesium daily from supplements, in addition to dietary intake. The tolerable upper intake level for supplemental magnesium is 350 mg per day according to the NIH. Timing matters: sleep-focused forms should be taken 30 to 60 minutes before bed. Stacking multiple forms can target different systems simultaneously.

Recommended Daily Intake

Group	RDA (mg/day)	Typical Supplement Range
Adult men (19–51+)	400–420 mg	200–400 mg supplemental
Adult women (19–51+)	310–320 mg	200–350 mg supplemental
Athletes / high stress	Higher requirements	300–500 mg supplemental
Older adults (65+)	420 mg (men) / 320 mg (women)	300–400 mg supplemental

Important distinction: elemental magnesium vs. compound weight. A label reading “500 mg magnesium glycinate” does not mean 500 mg of elemental magnesium. Magnesium glycinate is roughly 14 percent elemental magnesium by weight, so 500 mg of the compound delivers about 70 mg of actual magnesium. Always check the Supplement Facts panel for the elemental magnesium content, which is what counts toward your daily intake.

Timing Strategies

• Sleep forms (glycinate, threonate): Take 30–60 minutes before bed. This is consistent across Huberman, Attia, and the clinical literature.
• Energy forms (malate): Take in the morning or early afternoon with a meal.
• General deficiency (citrate, chloride): Take with meals for better absorption. Split doses if taking more than 200 mg at once to reduce GI issues.
• Exercise recovery: Post-workout or with dinner.

Stacking Multiple Forms

Both Huberman and Attia stack multiple magnesium forms to target different systems. A practical stacking approach based on their reported protocols:

• Morning/afternoon: Magnesium malate or citrate (100–200 mg elemental) for general repletion and energy
• Evening (30–60 min before bed): Magnesium threonate (100–145 mg elemental) for cognition and sleep, plus magnesium glycinate (100–200 mg elemental) for relaxation and sleep

Upper Limits and Safety

The NIH’s tolerable upper intake level (UL) for supplemental magnesium is 350 mg per day. This applies to magnesium from supplements and medications, not from food. Note that Attia reports taking roughly 1 gram of total elemental magnesium daily, well above this threshold — he has emphasized on The Drive that he monitors his levels and that this protocol is supervised. Stanfield, by contrast, keeps his supplemental dose at 126 mg, well below the UL, and cautions against megadosing without medical guidance.

The most common side effect of excess supplemental magnesium is GI distress (loose stools, diarrhea), which is typically self-limiting and resolves with dose reduction. This is most pronounced with oxide and citrate forms. In people with healthy kidney function, excess magnesium is efficiently excreted in urine. People with kidney disease should consult a physician before supplementing, as impaired excretion can lead to dangerously high magnesium levels.

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Best Magnesium Supplements (2026)

Answer capsule: The best magnesium supplement depends on your primary goal. For sleep, magnesium glycinate and threonate lead the field. For cognition, threonate is the standout. For general deficiency correction, citrate offers the best value. Below are top-rated options in each category based on third-party testing, form quality, and value.

Product	Form(s)	Elemental Mg per Serving	Best For	Third-Party Tested	Price Range	Link
Magtein (Life Extension)	Magnesium L-Threonate	144 mg	Cognition, sleep	Yes (NSF)	$$$	Check current pricing on Amazon
Doctor’s Best High Absorption Magnesium	Magnesium Bisglycinate Chelate	200 mg	Sleep, general deficiency	Yes	$$	Check current pricing on Amazon
Thorne Magnesium Bisglycinate	Magnesium Bisglycinate	200 mg	Sleep, anxiety, general	Yes (NSF Certified for Sport)	$$$	Check current pricing on Amazon
NOW Foods Magnesium Citrate	Magnesium Citrate	200 mg	General deficiency, budget	Yes (GMP)	$	Check current pricing on Amazon
Momentous Magnesium L-Threonate	Magnesium L-Threonate	144 mg	Cognition, sleep (Huberman-associated)	Yes (NSF Certified for Sport)	$$$	Check current pricing on Amazon

What to Look For When Choosing a Magnesium Supplement

• Third-party testing: Look for NSF, USP, or ConsumerLab certification. This verifies that the product contains what the label claims and is free of contaminants.
• Elemental magnesium content: Always check the Supplement Facts panel for elemental magnesium per serving, not just the total compound weight.
• Chelated forms: The term “chelated” indicates the magnesium is bound to an organic molecule (amino acid or organic acid), which generally improves absorption.
• Minimal fillers: Avoid products with excessive fillers, artificial colors, or unnecessary additives.
• Form matches your goal: Do not buy threonate if your main concern is constipation. Do not buy oxide if your main concern is cognition. Match the form to the purpose.

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Why I Chose Glycinate and Never Looked Back

I’ve talked about magnesium glycinate in my sleep article, but here’s the fuller picture on why I chose this form specifically and why the form matters more than most people realize.

Magnesium is magnesium, right? Not even close. The compound it’s bound to completely changes what it does in your body. Glycinate is bound to glycine — an amino acid that’s calming and supports sleep. Threonate (the form Huberman recommends) crosses the blood-brain barrier and targets cognitive function. Citrate is mostly used for gut motility. Oxide is cheap and barely absorbs — it’s basically a laxative.

I went straight to glycinate because my primary goal was sleep quality, and it delivered within the first week. I considered threonate based on Huberman’s recommendation but the cost is significantly higher and the glycinate was already working. I didn’t see the point of paying 3x more for a different mechanism when the one I had was doing its job.

The thing about magnesium that doesn’t get enough attention: most people are deficient and don’t know it. It doesn’t show up well on standard blood tests because your body pulls it from bones to maintain blood levels. You can test “normal” while your intracellular magnesium is tanked. Symptoms are vague — poor sleep, muscle cramps, anxiety, brain fog — so people blame other things.

At $15-20 a month for glycinate, this is the highest-ROI supplement in my stack relative to cost. If you take nothing else from this site, take magnesium. And don’t buy the cheap oxide form from the grocery store — you’re paying for a laxative, not a supplement.

Form matters more than brand for most supplements. I break down what to actually buy. The CoreStacks Longevity Report — free, weekly.

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Keep Reading

• Best magnesium glycinate supplements for 2026
• Best supplements for sleep
• Best time to take magnesium for sleep
• Magnesium glycinate vs threonate compared
• 7 signs of magnesium deficiency

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Frequently Asked Questions

Can you take too much magnesium?

Yes. The NIH’s tolerable upper intake level for supplemental magnesium is 350 mg per day for adults. Exceeding this can cause gastrointestinal symptoms including diarrhea, nausea, and abdominal cramping. These effects are most common with magnesium oxide and citrate forms. In people with healthy kidneys, excess magnesium is excreted efficiently, so acute toxicity from oral supplements is rare. However, people with kidney disease face a serious risk of magnesium accumulation and should only supplement under medical supervision. Attia has reported taking approximately 1 gram daily under physician monitoring — this is well above the standard UL and should not be attempted without bloodwork and professional guidance.

What is the best form of magnesium for sleep?

Based on expert recommendations and available research, magnesium glycinate (bisglycinate) and magnesium L-threonate are the most recommended forms for sleep. Huberman takes both forms nightly. Stanfield selected glycinate for his Sleep supplement after reviewing the clinical literature. Glycinate offers the best combination of absorption, GI tolerance, and evidence for sleep benefits. Threonate adds cognitive benefits but costs more and delivers less elemental magnesium per dose.

Should I take magnesium in the morning or at night?

It depends on the form and your goal. Sleep-promoting forms (glycinate, threonate) should be taken 30 to 60 minutes before bed. Energy-supporting forms (malate) are better suited for morning or early afternoon. If you are stacking forms, a common protocol is malate or citrate in the morning with meals and glycinate or threonate in the evening before bed.

Does magnesium glycinate make you sleepy?

Magnesium glycinate has calming properties due to the glycine component, which acts as an inhibitory neurotransmitter. Some people do experience drowsiness, which is why experts recommend evening dosing. However, it is not a sedative in the traditional sense. Most people can take lower doses during the day without significant drowsiness, though sensitivity varies by individual.

How long does it take for magnesium supplements to work?

For sleep benefits, many people report noticeable improvements within the first week of consistent use. For correcting a systemic deficiency, research suggests it can take several weeks to months of consistent supplementation to meaningfully replete intracellular magnesium stores. Attia has noted on The Drive that magnesium repletion is not an overnight process and that patients should expect to supplement consistently for an extended period.

Can I get enough magnesium from food alone?

In theory, yes. In practice, it is difficult for most people. Stanfield has emphasized a diet-first approach, recommending leafy greens (especially spinach), nuts, seeds, legumes, and whole grains as primary dietary sources. However, he also acknowledges that declining mineral content in crops due to modern agricultural practices makes it challenging to meet the RDA through diet alone, which is why he includes a moderate supplemental dose in his protocol.

Is magnesium threonate worth the extra cost?

This is debated among experts. Huberman and Attia both take it and have discussed its unique ability to cross the blood-brain barrier. Human clinical trials show promising cognitive benefits. However, Stanfield has questioned whether the evidence justifies the significant price premium over glycinate, noting that several positive studies were manufacturer-funded and small. If cognition and brain health are your primary goals, threonate has the strongest mechanistic rationale. If sleep is your primary goal, glycinate may deliver comparable benefits at a lower cost.

Can I take magnesium with other supplements?

Magnesium generally stacks well with other supplements. Huberman’s full sleep protocol combines magnesium with apigenin and L-theanine. Magnesium pairs well with vitamin D3 (it is needed for vitamin D metabolism), zinc (often taken together as ZMA), and omega-3 fatty acids. The main interaction to be aware of is with calcium: while they are both essential minerals, very high calcium doses can compete with magnesium for absorption. Taking them at separate times of day is a common recommendation.

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Medical Disclaimer

The information provided in this article is for educational and informational purposes only. It is not intended as medical advice, diagnosis, or treatment. The content reports on what published research and named health experts have publicly stated about magnesium supplementation. CoreStacks does not make health claims and does not recommend specific supplements, dosages, or protocols. Always consult with a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you have a medical condition, take medications, or are pregnant or nursing. Individual responses to supplementation vary, and what works for one person may not be appropriate for another. Never disregard professional medical advice or delay seeking it because of something you have read on this website.

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