Physiology 101 of the Blood Brain Barrier (BBB)

The inside of blood vessels are lined with cells called endothelial cells, and in most parts of the body, there are small gaps between these cells. These gaps allow substances in the bloodstream to pass through the vessel walls.

But in the brain, the endothelial cells are grouped too closely together to allow substances to pass through so freely. These tight junctions, plus the glial cells that surround the outside of the blood vessels, makes up the Blood Brain Barrier. It’s still possible for some substances to cross the barrier (especially glucose and lipid-soluble substances), but for the most part, the brain is protected from the contents of the blood.

For this reason, some 95% of medications and supplements cannot cross the BBB.

Enter Magnesium Threonate

I wrote here about magnesium deficiency, its symptoms and causes. Several of the symptoms are potentially neurological in origin, including memory and concentration problems, depression, apathy, emotional lability, irritability, nervousness, anxiety, and insomnia. While some patients report that absorbable forms of magnesium (citrate, orotate, glycinate, taurate, or other chelated forms) will calm them down somewhat and even aid sleep, for most the effects are mild or not noticeable.

But there are some impressive animal studies suggesting that magnesium threonate has activity in the brain.

  • This study shows that magnesium threonate can restore memory deficits associated with chronic pain.
  • This study  shows that magnesium L-Threonate is helpful for memory and learning—enhancing the brain’s ability to form new synaptic connections in a process called neuroplasticity.
  • This study demonstrates that magnesium threonate reduces inflammation in the brain—suggested to have possible benefits for Alzheimer’s Disease.
  • This study uses magnesium threonate in Alzheimer’s mouse models, and demonstrates that magnesium threonate can prevent loss of synpases (connections between neurons) and helps reverse cognitive decline. (!!)

The Upshot:

It would appear that, unlike other forms of magnesium, Magnesium L-Threonate has the ability to cross the BBB and affect the neurological symptoms of magnesium deficiency. 

I looked and my usual suppliers don’t carry this particular form of magnesium. But as far as I can tell, this is a good one!