Magnesium

Why magnesium matters more than most people think

Magnesium is involved in over 300 enzymatic reactions in the human body. It's required for energy production, DNA repair, protein synthesis, muscle contraction, and nerve signaling. Despite this, an estimated 45-60% of adults in Western countries don't meet the recommended daily intake of 310-420 mg, depending on age and sex ^[1]. Standard serum blood tests miss most deficiency cases because less than 1% of the body's magnesium is found in blood serum. The rest sits inside cells and bones. That's why experts recommend red blood cell (RBC) magnesium testing for a more accurate picture of your actual status ^[2].

A 2024 review in Nutrients mapped magnesium's relationship to all twelve hallmarks of aging, from genomic instability and telomere attrition to mitochondrial dysfunction and chronic inflammation ^[3]. The takeaway is straightforward: low magnesium accelerates biological aging through multiple independent pathways. Epidemiological data backs this up. A dose-response meta-analysis of prospective cohort studies found that higher magnesium intake is associated with lower all-cause, cardiovascular, and cancer mortality ^[4].

Magnesium forms and which ones to choose

Not all magnesium supplements are equal. The form determines how well your body absorbs it and which specific benefits you get.

Magnesium glycinate is bound to the amino acid glycine. It has high bioavailability, is gentle on the stomach, and glycine itself has calming properties. This makes it a solid choice for sleep support and general supplementation. A 2025 RCT with 155 adults found that magnesium bisglycinate improved sleep quality compared to placebo ^[5].

Magnesium L-threonate is the only form shown to cross the blood-brain barrier effectively. A 2024 randomized controlled trial demonstrated improvements in both objective sleep quality (measured by actigraphy) and daytime functioning after six weeks of supplementation ^[6]. A separate 2025 trial confirmed benefits for cognitive performance and sleep in adults aged 18-45 ^[7].

Magnesium citrate has good absorption and a mild laxative effect. It works well for people dealing with constipation alongside magnesium deficiency, but it's not ideal if you already have loose stools.

Magnesium taurate combines magnesium with the amino acid taurine and has the strongest evidence base for cardiovascular applications, particularly blood pressure support.

Magnesium malate is paired with malic acid, which participates in the Krebs cycle. Athletes and people with chronic fatigue often prefer this form for energy production support.

Magnesium oxide contains the highest percentage of elemental magnesium per capsule but has the poorest bioavailability. Most of it passes through unabsorbed.

What the research says about blood pressure and heart health

Cardiovascular health is where magnesium supplementation has some of its most robust evidence. An umbrella meta-analysis of randomized controlled trials published in 2024 found that magnesium supplementation reduces systolic blood pressure by approximately 1.25 mmHg and diastolic pressure by 1.40 mmHg ^[8]. Those numbers sound small, but at a population level, even modest blood pressure reductions translate to meaningful decreases in stroke and heart attack risk. A separate meta-analysis covering 38 RCTs with 2,709 participants confirmed these findings across median doses of 365 mg and 12-week intervention periods ^[9]. Higher dietary magnesium intakes are also associated with significantly lower risk of ischemic heart disease and cardiovascular mortality.

Magnesium, sleep, and stress

Poor sleep and chronic stress both deplete magnesium, and low magnesium worsens sleep and stress. It's a cycle worth breaking. A meta-analysis of RCTs in older adults found that magnesium supplementation reduced sleep onset latency by an average of 17 minutes compared to placebo ^[10]. Magnesium supports sleep by activating the parasympathetic nervous system, regulating GABA receptors, and helping to control the stress hormone cortisol. For sleep specifically, magnesium glycinate and L-threonate have the best clinical evidence, taken 30-60 minutes before bed.

Signs of magnesium deficiency

Early deficiency often goes unnoticed. The kidneys compensate by reducing urinary excretion, masking the problem for months or years. As deficiency deepens, symptoms become more apparent: muscle cramps and twitches, trouble sleeping, anxiety and irritability, heart palpitations, fatigue despite adequate rest, and headaches or migraines. Certain groups face higher risk: older adults (absorption decreases with age), people with type 2 diabetes, heavy drinkers, anyone taking proton pump inhibitors or diuretics long-term, and athletes who lose magnesium through sweat ^[1].

How much to take

The RDA is 310-320 mg for women and 400-420 mg for men, from food and supplements combined. The tolerable upper limit from supplements alone is 350 mg per day. Most clinical trials showing benefits use 200-400 mg of supplemental magnesium daily. Start with a lower dose and increase gradually if you experience any digestive effects. Good dietary sources include pumpkin seeds (156 mg per ounce), almonds (80 mg per ounce), spinach (78 mg per half cup), and dark chocolate (65 mg per ounce) ^[1].