Boron in supplement capsules are usually made from borax anyway; least resistance, cheap and easy for me is borax, but others prefer differently. Your choice.
2 mg is not enough to boost testosterone. Even the RDA is 3 mg, far to low to have a therapeutic value IMO.
Just to clarify; boric acid is when you mix sulphuric acid with borax. Not meant for internal use, I actually didnt know that they used it in Asia as a food preserver; now I know why it looks fresh hour after hour down there.
-and the rising libido when down there, yes who knows!