Most of us I probably don’t think about how much magnesium we consume, but our bodies couldn’t function without it. We each typically contain about 25 grams of magnesium, more than half of which is stored in bones. The rest is distributed to cells throughout the body, participating in hundreds of essential chemical reactions, including building DNA and proteins and sending signals within our nervous system and between our brain and the rest of our body.
But it is not because our cells – and in particular our neurons – need magnesium that this additional magnesium will make them work better. Not only that, but ingesting more of that element doesn’t mean it reaches your brain or a specific part of your body.
In supplements, magnesium is not only present alone, but is part of a compound generally referred to as a “magnesium salt.” This must dissolve to release Mg²⁺, the ionic version that our body uses. How much magnesium actually enters your system (as opposed to being eliminated) depends on a variety of factors, including the dose, the contents of your stomach, and the amount of magnesium already in your body. In other words, the higher the dose, the less magnesium is absorbed.
That’s all if the supplement dissolves in the first place. Magnesium oxide, which typically forms the basis of the cheapest pills offered, does not break down so easily. In reality, magnesium oxide supplements act primarily as laxatives, drawing water into the intestines to flush out excess salt.
This is where marketing comes in. There are other types of magnesium compounds that dissolve better. Laboratory tests have shown that magnesium citrate, for example, has the highest bioavailability. Despite the fact that all of these salts still break down in the gut, some supplement labels also claim that their specific chemical blend targets magnesium directly to certain parts of your body, like your muscles or your brain.
These claims are often based on experiments using rodents, and animals are typically given magnesium long-term in higher doses than found in a pill. A study in rats found that a salt called magnesium L-threonate increased the amount of magnesium in the brain and improved some manifestations of learning and memory. This is the basis of some of the most overzealous marketing in the supplement world, which proclaims that this special salt will deliver magnesium directly to your brain.
There are studies on humans, but that’s not really what they say. A few small randomized trials reporting improvements in some cognitive or sleep tests have been conducted, but there are several important caveats. Some studies tested a mixture of substances, lasted only a few weeks, or analyzed a very limited number of results. Many of these studies also cannot be considered independent, because they were funded by the supplement manufacturers or led by their staff.
Additionally, the studies, for completely understandable reasons, did not measure brain magnesium content. So maybe a little more seeps into your gray matter, but based on the scientific understanding of how these salts are processed, in all likelihood a brain-focused magnesium supplement is still just an expensive laxative.
This story was originally published on WIRED Czech Republic and Slovakia and was translated from Czech.
Gn Health
