Magnesium that has Low Bioavailability is larger in size and lacks the proper electrical charge.
Extra work must be done by your body to dismantle it into smaller parts and add an electrical charge in order to cross your cell membranes to get to where it's needed the most.
The conversion process of the magnesium into a useable form costs you energy.
Magnesium that has High Bioavailability requires no work on your body's part and slips right through your cell membranes to the inside of your cells, where it's most needed for critical enzymatic and energy production processes.
This type of magnesium is much smaller in size and has just the right electrical charge that allows it to effortlessly pass through your cell membranes. No extra work is required to break it down any further.
This mineral form is called "Ionic" and it's pretty hard to find.
Well these days anyway
In the past we found ionic forms of magnesium in our food supply.
Sadly, modern farming practices have killed most of the beneficial fungi that convert inorganic minerals found in the soil into the organic (Ionic) usable form by plants.
Plants are at the bottom of the food chain. If they lack minerals, the rest of your food is going to lack minerals as well.
There is a very unique way to get just the right amount of Ionic Magnesium for deeper more restful sleep and more energy during the day.
It's pretty neat and has some huge secondary benefits as well.
I also think it's pretty cool that it's "big in Japan"...makes sense as they're one of the longest-lived societies in the world...