Long ago…b4 Q…I was digging on borax and the correct dosing. I came across some stories about the old timers used to wet and dip their index finger in borax up to the first joint and then lick it off.
I don't have the actual mg/kg numbers handy atm, but back then I did; and did some experiments based on the stories. I weighed out a known quantity of borax and wet my index and dipped it, then rinsed and repeated for 10x to get an average. Guess what? It was exactly what the medically recommended dosage was. I guess the surface area adjustment from small to large peeps makes the dose close.
This is how I still do it today. For anyone thinking about this, do your own research, but at least now you know how it'll come out.
Sodium tetraborate. Sodium, boron, oxygen, and hydrogen. It's the boron you're after.