Magnesium is a cofactor in more than 300 enzymatic reactions that support energy production, muscle and nerve function, blood glucose control, blood pressure regulation, protein synthesis, and bone health. Despite its fundamental role, a large portion of adults fall short. Recent analyses of NHANES data indicate that roughly two-thirds of U.S. adults show signs of chronic latent magnesium deficiency (serum magnesium below approximately 2.06 mg/dL), with higher rates among those with diabetes, hypertension, or kidney disease.
Not all magnesium supplements are equal. The form determines absorption, tolerability, and how likely you are to actually raise magnesium status without digestive side effects. Magnesium glycinate (also called magnesium bisglycinate) — magnesium bound to the amino acid glycine — stands out for its bioavailability and gentle profile. Here is what the research shows.
Magnesium glycinate is a chelated form in which one magnesium ion is bound to two glycine molecules. This structure allows absorption partly through dipeptide transporters in the intestine, in addition to standard magnesium pathways. Organic forms of magnesium generally outperform inorganic ones (such as oxide) in bioavailability studies.
Glycine itself is an inhibitory neurotransmitter involved in calming pathways and has independent research supporting modest improvements in sleep quality when taken in gram amounts before bed. The combination makes glycinate a preferred option for evening use and for people sensitive to the laxative effects of other forms.
In vitro and comparative studies consistently rank magnesium bisglycinate among the better-absorbed forms, with some dialysis and cell-model data showing bioavailability around 66–67%. Human data show advantages in certain populations: in patients with impaired intestinal absorption (e.g., after ileal resection), magnesium diglycinate was better absorbed than oxide in those with the poorest oxide absorption and was better tolerated overall.
Two capsules daily, ideally in the evening.
