Magnesium is one of the essential minerals that has many biological roles in the human body. It is of particular importance for proper brain function and mental well-being as it plays a key role in nerve transmission. Magnesium has been shown to have a neuroprotective effect and it may combat excessive excitation and death of neurons. 
A deficiency in magnesium has been linked to many neurological disorders, such as anxiety, depression, migraine, Alzheimer’s disease, and others. 
Some studies have shown that most people nowadays do not get enough magnesium from their diet,  which explains why magnesium is one of the most commonly taken dietary supplements.
When it comes to choosing a magnesium supplement, however, things can get a little puzzling. There are more than a dozen different types or forms of dietary magnesium to choose from. Some of the popular choices include magnesium citrate, oxide, sulfate, chloride, and more recently; L-threonate. These are all different salts of magnesium, and this article will focus on magnesium L-threonate.
What is Magnesium L-Threonate?
Magnesium L-Threonate (MgT) is the magnesium salt of L-threonic acid or L-threonate. The latter is a sugar acid and a metabolite of vitamin C. Magnesium L-threonate is a chelate where L-threonic acid acts as the chelating agent.
This compound consists of two L-threonate molecules bonding with one magnesium ion. By mass, MgT contains about 8% elemental magnesium, i.e. there is about 8mg elemental magnesium in each 100mg of magnesium L-threonate.
Unlike other naturally occurring forms of magnesium, MgT is a novel, lab-made chemical that does not occur in nature, although it is made up of two natural components.
Magnesium L-threonate was discovered by a team of MIT researchers, and it is commercially available as a patented compound called Magtein, which was developed by Magceutics.
What’s So Special About Magnesium L-Threonate?
The main objective was to create a form of magnesium that addresses two of the main problems with most other forms of magnesium on the market: It needs to be efficiently absorbed in the GI tract, and it needs to efficiently cross the blood-brain barrier.
As a chelated magnesium, it has indeed been shown to have better absorption rate and higher bioavailability than other ionic magnesium compounds. Additionally, L-threonate acts as a carrier molecule that helps magnesium penetrate the blood-brain barrier more efficiently.
It is worth noting that other forms of magnesium found in food and dietary supplements also do cross the blood-brain barrier, and that’s how your brain normally gets the magnesium it needs. However, no other compound has been shown to be as effective as MgT for raising brain levels of magnesium, which makes it a promising potential treatment for certain neurological disorders that are linked to low brain levels of magnesium, such as Alzheimer’s disease.
The Main Pros
- Increases Brain Magnesium Levels: MgT has been found more effective than other forms at penetrating the blood-brain barrier and causing a significant increase in the levels of this mineral in the brain.
- May Improve Cognitive Function: Since magnesium has an important role in neural conduction and brain function, raising its levels in the brain through supplementation with MgT has been studied as a means of cognitive enhancement. There are promising results in this regard, especially for older people who suffer from magnesium depletion and age-related cognitive decline.
- Higher Bioavailability: Higher amounts of MgT are absorbed in the GI tract compared to other forms, which means a lower dosage is required to obtain a noticeable effect as less magnesium is wasted in the GI tract.
- Does Not Cause Diarrhea: Some non-chelated magnesium salts break down into ions in the GI tract, where magnesium ions can have a laxative effect. As a chelated form of magnesium, MgT does not break down and gets absorbed as a whole intact molecule. MgT is easier on the stomach and is not known to cause diarrhea or loose stool.
The Main Cons
- Limited Evidence: The claimed “cognitive enhancement” effect of MgT is based on small-scale research and preliminary studies. Although the results have been promising so far, larger human studies are needed to reach solid conclusions on the efficacy and safety of long-term supplementation with MgT.
- Unnatural Form: While both magnesium and L-threonic acid are naturally occurring substances, the compound magnesium L-threonate does not exist in nature in this form. I’d say it’s more like a “pharmaceutical magnesium”.
- A Commercial Compound: Magnesium L-threonate is a patented chemical that is sold commercially under the brand name Magtein. One of the cofounders of the company that sells Magtein; Guosong Liu, is also one of the researchers involved in the clinical trials that investigate the benefits of this compound.
- Overstated Benefits: I think some of the claims about the benefits of MgT are a little bit overblown by the manufacturer and branded products that use this ingredient. It may be helpful in cases of anxiety, depression, brain fog, insomnia, etc., which are linked to magnesium deficiency, but if you are otherwise healthy, you probably won’t notice any change after taking this supplement.
- Costly: This is the most expensive magnesium supplement on the market that I am aware of.