National Alzheimers Disease Institute


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Cognitive Impairment Reversed by Magnesium L-threonate

P. Anthony Chapdelaine, Jr., MD, MSPH, Exec. Dir./Sec.*

A double-blind, placebo-controlled study of older adults aged 50 to 70 who complained of memory problems, anxiety, and sleep problems was done. It evaluated whether magnesium L-threonate could increase the body concentration of magnesium and thus improve cognitive impairment. These adults were shown to have “executive function decline, and a mild cognitive impairment” compared to cognitively normal adults of the same age). Adults in this study took magnesium L-threonate (dosage based on body weight was between 1.5 and 2.0 grams daily) or a placebo (“sugar pill”).

Although about 30% of the adults who took the magnesium L-threonate did not respond, about 70% did respond.

The Results

Magnesium L-threonate improved overall cognitive ability; decreased fluctuations in cognitive ability; increased body concentrations of magnesium; and reversed existing declines in cognitive abilities. “Brain Age” was estimated using The Trail Making Test – Part B (TMT-B) which “assesses executive function as well as impulsivity, visual search, visual attention, and motor speed.”  For instance, the brain age of a person who is slower performing the TMT-B has a brain performing at an older age than the person’s actual physiological age. The average decrease in brain age for all the adults who took the magnesium L-threonate was 9.4 years, and their brain age nearly returned to their actual physical age. The placebo group of adults showed no improvement. When looking only at the adults who responded to the magnesium L-threonate (based on the levels of magnesium in the red blood cells), the average decrease in brain age was a remarkable 14.6 years!

Magnesium appears to improve the brain’s synaptic density (the more connections in the brain the higher the density, therefore, the better the cognitive function), and magnesium improves plasticity (which is defined as how well the synapses can change when confronted with a new stimulus). Ordinary magnesium is not able to cross the blood-brain barrier very well. Magnesium L-threonate increases the transport of magnesium across the blood-brain barrier. This is thought to be reason it works so well to improve cognitive decline.

* The National Alzheimer’s Disease Institute is a project of The National Fund for Alternative Medicine


  1. Guosong L, Weinger J G, et al, “Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial,” J Alzheimers Dis, 2016, 49(4), Pages 971–990.