What is the Best Magnesium Dose & Form? (14 Studies Reviewed)

Brad argues that the first mistake is to jump to supplements based on observational data. He emphasizes that magnesium deficiency often stems from a diet high in processed refined foods where magnesium is stripped away. By shifting to whole foods, you not only boost magnesium but also improve overall health. He cites that foods containing dietary fiber generally provide magnesium, and plant-based sources are richer than meat. This hard work is critical to actually benefit your health, and supplements should only supplement a ready healthy diet.

Brad explains that the recommended daily intake is 420 mg for men and 320 mg for women. Many people are deficient because of processed foods. Instead of high-dose supplements, he advocates a low-dose approach: his own sleep supplement contains 126 mg of magnesium glycinate, and his micro vitamin contains magnesium taurate. This amount helps him reliably hit his daily target. He stresses that just because he takes it doesn't mean others should, and that the supplement should supplement a healthy diet, not replace it.

Brad uses magnesium oxide as an example: it's cheap and has a high elemental percentage (60%), so you only need 700 mg of magnesium oxide to get 420 mg elemental magnesium. But supplement companies often put '400 mg of magnesium oxide' on the label, and consumers mistakenly think they're getting 400 mg of elemental magnesium, when they're only getting 240 mg. He warns that you need to be very careful when reading the label. This applies to all forms; for magnesium citrate (11% elemental), you'd need 1,145 mg to get 126 mg elemental. He advises looking for the elemental amount explicitly stated.

Brad reviews sleep studies: a trial in 46 elderly patients found magnesium increased sleep time, sleep efficiency, decreased insomnia scores and sleep onset latency, raised melatonin, and lowered cortisol. A 2021 meta-analysis found magnesium reduced time to fall asleep by about 17 minutes in older adults with poor sleep. A 2022 meta-analysis reported improvements in at least one sleep aspect in 5 of 8 trials. He chooses magnesium glycinate because glycine also improves sleep. His sleep supplement contains 126 mg of magnesium glycinate, which he takes at night.

Brad explains that the body tightly controls blood magnesium, so serum levels remain normal even when tissue and bone stores are depleted. He sees patients who have paid for blood tests and misinterpret normal results as indicating adequate magnesium. He advises that if you're meeting the RDI through diet and possibly a low-dose supplement, testing is unnecessary. He uses the engineering maxim 'The best part is no part. The best process is no process.' to emphasize avoiding a flawed test.

Brad explains that even with a good diet, reaching the RDI (420 mg men, 320 mg women) can be challenging due to declining nutrient levels in crops. He therefore includes 126 mg of magnesium (about 30% of RDI) in his sleep supplement and micro vitamin. He emphasizes that this is a supplement to a healthy diet, not a replacement, and that just because he takes it doesn't mean others should. The dose is deliberately low to avoid over-reliance on pills and to capture the other benefits of whole foods.

Brad reviews the human evidence: a small industry-funded study found a small increase in executive function but no improvement in other cognitive domains. Another study at Stanford in 17 dementia patients, completed in 2016, showed no clinically meaningful improvement in cognitive function when results were posted in 2021. He concludes that the expensive form is not justified by current data, and he prefers amino acid-bound forms like glycinate and taurate.

Brad explains that many people, including his patients, cite impressive-sounding statistics from observational studies as justification for taking large doses of magnesium. However, these studies cannot prove causation; higher magnesium intake might simply be a marker of a better diet or more exercise. Therefore, the correct first step is to address the underlying dietary cause of low magnesium by eating more leafy greens, legumes, nuts, seeds, and whole grains. Only after optimizing diet should one consider a low-dose supplement to fill remaining gaps. This approach ensures you get the fiber, phytonutrients, and other benefits of whole foods.

Brad details that an adult body contains about 25 grams of magnesium, with 50-60% in bones and most of the rest in soft tissues; less than 1% is in blood. Blood magnesium is under tight homeostatic control, so serum levels correlate poorly with total body stores. Consequently, a person can have normal blood magnesium yet be deficient overall. He notes that other methods (saliva, urine) are also unsatisfactory. His advice: instead of relying on a flawed test, ensure adequate dietary intake to meet the RDI, which makes testing unnecessary for most people without absorption disorders.